GM'S Bridge To Fuel Injection: The Electronic Feedback Carburetor

[@gregorymalchuk272]

These electronic carburetors were marvelous from the standpoint of getting carburetors to achieve clean emissions, operate under closed loop control with a 3 way catalytic converter, and not stink like unburnt fuel. They were unfortunate in that they had all of the disadvantages of a carburetor: finicky cold starting, vapor lock, float bowls that flood and starve during bumps and hard braking (even happened in Motor Week tests), choke unloaders, choke heaters, knock off cams, fast idle, jets and idle circuits to get plugged, etc. Plus the inscrutability of a computerized electronic control system. The GM TBI systems that succeeded electronic carburetors were vastly superior in terms of reliability, cold starting, and customer experience.

[@shadowopsairman1583]

A non electronic carb can be tuned for it as well,

[@stevebot]

@@shadowopsairman1583 A carburetor is like a clock with a dead battery, it’s right twice a day, when the temperature, pressure, fuel quality and conditions match settings. Even that is optimistic.

[@KC9UDX]

@stevebot that's almost true of most fixed bore carburettors. Fuel injection can be just as bad or worse.

[@johnssonsmixed8303]

I think I've got mine dialed in right except for the choke. She runs pretty good otherwise

[@matthewfredrickmfkrz1934]

Dunno about the e carb but the tbii is great

[@cruze1953]

Boy did this bring back memories. How many of you went to the GM Training Center in Burbank? I took the classes for these carbs. Fred Woodley was the instructor. To get the idle mixture screws out I made shallow cuts with a hack saw on both sides of the adjustment screws then punched out the hardened steel insert. The engines idled like a champ after backing them out a full turn. The tools were called "Double D". I still have mine, I think I used Lisle brand. I remember some choke pull-offs had spring tension adjustment screws accessed thru the vacuum nipple port. I used to leave my house at 530am to beat the traffic on the way to GM class. I got there an hour early each day and would watch the Olympic ice skaters train at the rink next door.

[@davidrte.664]

I went to class there in late 1980. Grat instructors at that time. I don’t remember his name but he was Good.

[@marcs.6258]

I spent 8 weeks (?) in late '77 attending an apprentice level program at the Burbank facility. Don't recall any instructor's names. Ten years as a Buick tech starting in '78. I did meet Bill Trevor after he retired.

[@C7Zaol]

I used to make a killing rebuilding these when I still lived in CA. Shops would want $1000 or more to fix them so that the cars would pass the smog inspection. I felt bad charging $200 ( plus parts ) but I could knock them out left and right and they always ran awesome.

[@SurnaturalM]

I never had any troubles rebuilding and adjust these quadrajets. But I have a lot patience as I rebuild and restore clock, juke-box and vintage electronic.

[@shadowopsairman1583]

I've overhauled a 350 TBI module, pretty simplistic design, only trouble can be from the MAP Sensor, IACV or TPS going bad.

[@locobrown]

it's rabbit hole indeed. There's lots of variables. If you have the original factory carburetor that came with your car, and if you rebuild the engine to factory specs, you will be able to tune it correctly accordingly. If you don't have the original carb but a rebuilt one from a shop, you'll be in a world of hurt. Remanufactured carbs are just that, built to generic specs tuned only to get you going. In regards to calibration, the idle tubes, the bypass air, air bleeds in the body or at airhorn, the primary jets, the primary rods, the secondary rods, the secondary rod hanger, the accelerator pump and it plunger springs, the condition of every spring, tps, the mixture control solenoid condition and whether or not the plunger is straight, air horn warpage, bowl body electrosis, primary throttle plates becoming deformed being oval shape from being wedged in the bores, throttle body vacuum leak through its shaft bores that need repair, throttle body and airhorn being mismatched can gravely affect tuning due to whether or not the idle air bleed valve are letter stamped (non adjustable), the non letter stamp valve are, the mixture screws are dependent on what kind of idle air bleed valve your airhorn has, gasket selection, needle and seat, flooding, incorrect float or float settings ect. ect. ect. Its not a walk in the park. Specialty tools will allow you to adjust it's internals regarding their lean and rich stop settings and proper bleed valve setting. A dwell meter is paramount. You will be chasing down vacuum leaks, setting and or correcting tolerances. The choke mechanism, the primary and secondary pull off. Nozzle drip due to the throttle angle being too exposed for not having enough bypass air or due to worn out throttle plates. Some people adjust these carburetors wrong. They call them "Quadrajunks" or "Quadrabogs" but they are not that. The secondary airflaps are not adjusted correctly or the its pull-off is releasing too quickly. The feedback carburetor our C3s are not adjusted with an air gauge for best idle, they are adjusted with a dwell meter for best fuel mixture. If you adjust it using an air gauge or, if you adjust it by ear, you'll experience hard cold starts and the engine will not turn over until it heat soaks. Cranking the starter red hot. A well adjusted carburetor will not require pumping the gas nor setting the choke. The choke is set so that you can warm up the engine faster or if you live in a cold climate. The engine should turn over with a single flick of the key, no pumping on the gas, no setting the choke. I live in Southern Cali, and i rarely pump the gas if ever. 2-3 minutes idling as I get out the house and put my stuff in the trunk, it has warmed up enough that once i get to the end of street onto the road, its ready to roll. Quadrajets are universal, but once you radically rebuild your engine and slightly change its cam, you will need to modify it's internals and calibration based on your application. At this point, the maintenance manual for your car wont even matter. It's fun for sure, but you know what I'm talking about. A proper Quadrajet can rival any modern car regarding performance and mpg. One has to love it to endure the pains, the tears and the maddening rage it will provoke upon you. This will allow you to climb outta the rabbit hole or forever remain there.

[@dueljet]

My 1982 Malibu Classic has a Dual jet 210 atop the 229 ci v6. We have had the car since new. It has proven to be a great carburetor.... for the most part. It was a little crabby when cold and wasn't a fan of idling in super hot weather. The idle control has always been slow to kick up for AC demand. Great video!

[@TimPesola]

About 8-10 years ago I had an 84 Camaro with the feedback carb. At the time, I hated it because I didn’t understand it. At this point in time being older and wiser, I am starting to appreciate them for what they were at their time. Currently I’m trying to resurrect a 1980 Camaro that is bone stock and been sitting since 1994. When running, I will put what I have learned to the test to see if I can dial it in and get it to pass smog here in CA.

[@terrypikaart4394]

I do agree, most people say Qjet is junk because they don't understand them and cant make them work. That why there my favorite carb to rebuild and tune!..

[@76calidude]

Been trying to fully understand how they tick. Not too many guys out there that are willing to tune these. Found me a dwell meter...need the M/S adjusting tool..air bleed off tool and a manual. Would love to get that thing dialed. I hear they're smooth as silk once this is done..

[@garyradtke3252]

@@76calidude Lyle used to make the adjuster tools and the plug cutter for the idle mix plugs but I found grinding a slot below the plugs on the bottom of the throttle plate and using a small punch to drive out the p[lug was easier. If I remember the plugs are about 3/8"-1/2" long. Then use the flex idle mixture adjuster.

[@stevebot]

@@garyradtke3252 I still have a drawer in my tool box full of the tools to help make DualJet, QuadraJet and VaraJet carbs work right. May God have mercy on my soul.

[@dmandman9]

@@76calidudeI rebuilt them all the time. I never had any problems with them. The varajet were a bit more finicky. But the dual jet and Quadrajet feedback carburetors weren’t that bad at all .

[@rporestorations]

Keep checking ebay. The Kent-Moore sets come up every once in a while.

[@BlackPill-pu4vi]

My personal experience was having problems with the TPS (throttle position sensor). Because it was a sliding potentiometer, the contacts wore dead spots in the most used portion. Usually steady cruise. Those spots would reveal themselves as uneven performance or hesitation. After replacing many of them in my own personal vehicles, I retro-engineered my 85 Olds 88 w/ 307 to pre-computer configuration. I used the Q-Jet and HEI distributor from a donor 75 Olds Cutlass with the 350. The transformation was a success and I took out all the attending smog stuff. The engine bay looked so much neater and the engine ran like it was supposed to.

[@80fordmustang6]

Had a 86 custom cruiser with one a few years back honestly no complaints from me on it always run decently

[@rrmech11]

I rebuilt a few in my day. Setting the dwell reminded me of the g.m. Points system. I was 18 working in a ford dealership.

[@timsharpe3498]

I used to maintain a large fleet of cop cars and we had plenty of those feedback QUADRAJETs. There were some guys in our shop who were good at rebuilding them and some who were not. I actually enjoyed doing them. The last year they came on the Caprice was 1988 and they worked really well for the duration. However, the same carburetor on a 1986 Dodge Diplomat was nothing but trouble. I can only assume that they were much more sensitive on a smaller engine and demanded more tuning but they also had a major problem with losing the secondary emulsion tubes.

[@johnrose3169]

Nice video - Pretty concise summary of the feedback carburetors. One selling point of the Oldsmobile 5.7 diesels of that era was no carburetor or ignition system maintenance. Hindsight being 2020, the feedback Quadrajets were a far better deal, even if they did require some maintenance.

[@workingcountry1776]

Ironically I've owned both an olds 307 v8 with ccc and an olds 350DX diesel V8. The diesel got literally double the mpg city at 22-24mpg and cruising mpg was 30-36 mpg vs 16-18. Diesel started well in cold or hot and wild run on 50% used motor oil like it was its job

[@johneckert1365]

​@@workingcountry1776I've always liked the fuel economy of those Olds diesels. It's too bad GM didn't wait to release them until all the bugs were worked out. I'd really like to find a nice diesel Eldo, Toronado, or Riv one of these days.

[@johnrose3169]

@@workingcountry1776I’ve owned both as well. 1982 Bonneville Model G Diesel which got great mileage when it started. It had a chronic wait light/glow plug issue where there was no glow plug light since day one - it spent as much time at the Pontiac dealer as it did in my garage. It was replaced by a 1986 Pontiac Parisienne with the 307 that worked as intended, but mileage was nowhere near that diesel.

[@johnrose3169]

@@johneckert1365I really liked the Eldorados and Rivieras of that era.

[@johneckert1365]

@johnrose3169 Me too! Mom had an 83 Riv with the 307. Over 300,000 miles and it only needed 1 transmission, and 1 timing chain, along with other minor repairs I'm sure.

[@leegmc1985]

They just took patience and comon sense. I maintained s fleet of vehicles with these and the electronic Varajet E2SE. I re bushed the throttle plate on hundreds of both of these. Once the factory friction coating wore off. Great carbs actually.

[@raysievers8473]

Bought a 1984 Caprice in the early 90’s and still have the car. The E2ME has been faithful for 30+ years and 160,000 miles but only after it was adjusted correctly.

[@dandiegidio7729]

I think that's what was on my 86 regal 3.8. I put a petronix 50k volt coil in the hei and the carburetor automatically lowered the idle to probably around 400rpm and it would never stall. You could see the pulleys turning it was moving so slowly.

[@76629online]

I used to chop these things up with an axe. The problem with just about any q-jet is that they are very sensitive to vacuum signal...and the problem with THAT is that being on a carbureted engine....the engines wear at a faster rate than modern fuel injected ones do. The result of that is a degraded vacuum signal from the engine, which is detrimental to how a carburetor works in the first place. We won't even talk about the fact that during this era, just about ALL of GM's V8 and V6 engines suffered from premature camshaft failures which made it even harder for the carburetor to work correctly. I hated working on shit from this era. It was never easy.

[@ClassicOldsmobile]

So I hate to be one of those folks throwing out a car question for help but you seem to be the right guy. Recently had the fuel pump starting leaking externally on my olds 307 with 74k original miles. It’s in an 83 olds 98 if that is helpful information. After replacing pump it began flooding my carb blowing past the needle and seat. The carb was rebuilt by myself with very little knowledge 9 years ago. Figuring it’s been 9 years and 20,000 ish miles I figured it was due for a rebuild. Rebuilt carb replacing needle and seat and setting the m/c solenoid with a piece of metal blow gun nozzle cut down closest I could to 1.304 specified. I put the carb on and needle and seat issue was resolve. Adjusted air bleed using a dwell meter on 6 cylinder scale, car was still running at a faster idle than before. Found vacuum line broken and helped but feel I need to revisit adjustments. The question is do you see a reason I would random start getting a vehicle speed sensor codes randomly after about 5 minutes of warm up. Doesn’t happen every start and was not an issue before. Could this be a result of slightly higher idle on startup or did my 41 year old car decide it wanted more attention. I have an otc 2000 reader and was able to see speed sensor reads at 0 when parked and does slowly climb and almost perfectly matches the speedometer. Vehicle does not have cruise control either if that matters. I have service manuals but can’t find my data on vehicle sensor other than it is used for lockup. Thanks for any insight.

[@oldblueaccord2629]

Thanks again for the info. I never understood how they worked when they came out.

[@rporestorations]

Glad I could help.

[@oldblueaccord2629]

@@rporestorations I have one on my channel I massacred and run 50/50 gas and E 85. I ran it about 20 years. I got a couple of videos of it.

[@RodneyHayes-d3y]

I had an auto repair shop for thirty plus years and finely closed and retired in2019, the last one of these we had come in was on a 1987 fast back Montecarlo a customer had bought restored, and it was beautiful Only problem was a constant check engine light. I was the last shop in our town at that time doing carburetor work as everybody sent their head Acks to us. Rebuild, adjust. tweak the chock for our area and it drove out with a fully functional check engine that was now not on all the time

[@benbrown2119]

Little known fact about the E-Quadrajet: the ones built to be used on 5.0 liter engines were flow limited by way of a stop on the secondary air door shaft so that the secondary air doors would not fully open. Therefore, they do not flow 780 cfm like the older Quadrajets that came on larger displacement engines even though the main body and throttle plates are the same size.

[@shadowopsairman1583]

And can be overcome

[@locobrown]

just cut the tabs off

[@BlackPill-pu4vi]

I noticed that with my 85 Olds 88. I made the necessary corrections and got a proper WOT after that. Of course, the 307 was an asthmatic engine so, the performance gain was not much.

[@steamsoldier]

Been waiting for someone to make this video since youtubes inception, well done thank you for sharing!

[@rporestorations]

Glad you enjoyed it!

[@tomsparks3259]

I loved my 7028212 Quadrajet. It was an M4ME, but it was so easy to tune and it just flat worked on my racecar and tow vehicle.

[@joelsturken8005]

I’m still running mine here in California smog rules. I watched yours and other videos fabricated the measuring tools easy job when you understand sequence of events. Also installed an AFM gauge that tells me if it’s happy. Thanks for your help.

[@rporestorations]

Glad I could help. I lobe keeping these things going.

[@ronaldarchibald2506]

Mine absolutely sucked. Replaced it with a normal q jet and hei distributer. Removed bulb from check engine light. Car ran so much better.

[@76629online]

Yep. I fixed dozens of them this way.

[@mlc7boosted]

In 1997, my car during and after high school was an '83 Camaro with a 5.0L V8 and a Rochester Quadrajet. Coming from a '78 Toyota Celica with a 20R 4 cylinder engine, it was my first V8 and I thought it sounded cool when the 4 barrel would kick in; I guess that's what was happening during full throttle pulls. It sounded deep and throaty. The LG4 305ci V8 and 700r4 transmission was NOT fast but it was a really fun car and was reliable actually. The car was $1500 from a car lot across from my high school, but that's because it had a rod knock. So a new long block engine was purchased from Pep Boys and installed at a local shop along with a refurbished Rochester carburetor a few weeks later from Advance Auto Parts.

[@donreinke5863]

I would have promptly scrap piled the 305 and installed a 350.

[@mrraff69]

The most dialed in carb I ever had was on a 72 Buick 350. It didn’t have an electric choke but kick it down a couple times and it would fire up immediately. About 10 seconds I’d kick it down to a lower high idle and as I drove it would drop to low idle. I never touched a screw on the carb in my 5 years of driving. It never smoked and always got between 17-21 MPGs. It was in a Skylark convertible.

[@sasz2107]

I liked these, and I liked working on them. I thought the system was pretty ingenious. I thought these presented a unique challenge. You had to take the time to do the reading and to understand how these carburetors worked. But I was interested, so I did that. I found I was able to get the GM cars that had these carburetors running very well. I sort of miss having these cars that had the feedback carburetors around to work on!

[@davidrte.664]

Rebuilt many of those carbs, was working For Chevy when they came out. I loved working on them seldomly had a problem with them. I also worked for Ford in the late 70’s when the VV 2700 came out. They were pretty touchy on a cold start. We would have the owner leave it over night and that in most cases. Prevented a comeback. Also we emphasized the importance of to the customer of keeping up with a clean air filter and air horn gasket. That makes a big difference especially with the VV carbs. I enjoyed doing carb work. EFI performs better but there is just something very satisfying of turning that key and hearing that engine purr when you rebuilt the carb. Plugging in a scanner reading the scan data just isn’t the same.

[@ToddsHouseofSpeed-uq5sp]

The Q-jet is THE best street / mild performance carburetor, period. Excellent fuel metering, very tunable. The later electronic version, just as good for its intended purpose. You drill out the idle screw caps with an aircraft drill bit, to access base idle fuel trim. The metering rod adjustment was very straight forward with the ( aforementioned) gauge.

[@ckratzet5286]

Adjusting idle screws indicate the lean limit m/c stop is fucked up.

[@ckratzet5286]

in closed loop.

[@ToddsHouseofSpeed-uq5sp]

@@ckratzet5286 Hi, I disagree based on my experience working on hundreds of those when new. GM set the throttle plate more open at idle, then turned the mixture screws in at least 1-1/2 turns to achieve a lean idle w/o stalling. The mixture control solenoid lean / rich limit does not come into play until off idle transition. Also, the fuel trim window was very narrow on the CCC. It's much easier to trim slightly rich mixture to optimal VS trying to enrich an already lean mixture 🙂

[@ckratzet5286]

@@ToddsHouseofSpeed-uq5sp Go to 100% d.c. and it dies closed loop. Open/Closed loop needs to be specified.

[@krugtech]

i think there was an autolite carb that did the same with a stepper motor as opposed to a solenoid. I had an amc spirit with one and I just disconnected the stepper motor when it was on the rich side of sweeping through the range on bootup. car ran real good.

[@eldoradony]

I remember them well. I have rebuilt many Quadrajets successfully with minimal knowledge of how the system actually works. Your explanation got me curious. How about doing a video of the actual setup and special tools you mentioned. I may never see another one in my shop but this old dog would like to learn a few new tricks.

[@rporestorations]

I've actually done a few tool and calibration videos in years past. Check the "Electronic Carburetor" section on the page.

[@Samuel_el_toro]

I have the thexton adjustment tool kit for a Feedback Quadrajet. They were so valuable back in the day. If that solenoid was one screw out you would get a check engine light!

[@rporestorations]

Yep!

[@ToddsHouseofSpeed-uq5sp]

Also, a few comments here about the CFM of earlier units are incorrect. The standard Q-jet was rated @750cfm. GM enlarged the primary venturi ( but not the throttle plates) to flow 800cfm specifically for high performance Olds, Pontiac, Buick 455 engines 😅

[@scottspilis1940]

Had one of these in the mid 1980’s on a 5.0l LG4 application for a Pontiac Firebird.. Problem was that if you tried to rebuild it back then the rebuild kit was woefully inadequate regarding the gages, special parts and instructions you were given. You knew nothing of where to set solenoid for the dancing needle and no mention of the dwell procedure was made. I got mine as close as I could and it ran Ok, but not as sharp as when it was brand new. Finally bit the bullet and took it to the dealership for a carb tune. He told me everything I didn’t know, and said I came surprisingly close considering what I had, or more accurately, didn’t have, to work with. Could have used this video back then.

[@rporestorations]

The carb kits are even worse now.

[@donreinke5863]

Fun fact. The 1971 Ford 429 Cobra Jet was factory equipped with a Rochester Quadrajet, I have a 429 intake manifold in my shed that has the Quadrajet mounting pattern. The intake ports are huge. The 429 Super Cobra Jet used a Holley carb.

[@timsharpe3498]

This is true. Ford also borrowed the Harrison A6 AC compressors and disguised them with motorcraft decals. Then they ran commercials bragging about how quiet and refined their new LTDs were. 😂

[@donreinke5863]

@@timsharpe3498 The Ford, Lincoln and Mercury models that used the GM Frigidaire/Harrison AC compressors rather than York (aluminum) or Tecumseh (cast iron) A/C units were often also equipped with GM Saginaw power steering pumps as were nearly all Chrysler corporation and American Motors vehicles in the late 60s-70s. 1971-73 Mustangs and Cougars also used the GM Saginaw power steering gear. However, midsize Buicks Oldsmobiles and Pontiacs with V-8 engines and 3 speed manual transmissions used a Ford "Dearborn 303" transmission as GM did not make a heavy duty 3 speed. Chevrolet, and of course Cadillac division did not use the Dearborn 303

[@timsharpe3498]

@@donreinke5863 I totally understand why they used the A6. I owned a Cougar that had the Tecumseh compressor and it sounded awful and had quite a bit of vibration.

[@hannibalbarca8670]

Another excellent video. Thank you

[@rporestorations]

Thanks!

[@donreinke5863]

I have a box of these in the attic, mostly for the parts that fit REAL Quadrajets. I used to pull these things off and replace them with regulat Quadrajets scavenged from wrecking yards. I considered them useless and troublesome..and still do. Getting rid of the check engine light was easy. I used to run a wire from the light to an oil pressure switch teed into the oil galley along with the standard oil pressure light switch. It would mimic the normal operation of the check engine light perfectly. Emission cheats were...and are...a specialty

[@rwdplz1]

Modern mechanics can't even work on fuel injection systems from this era, I'd LOVE to see them tackle these.

[@TheMrDarius]

Fuel injection systems back then were way simpler than today.

[@skylinefever]

I think about how my mom's 1985 Nissan Maxima was a constant pain, but miraculously, the EFI did not cause a problem. I could just imagine the in tank fuel pump or some critical sensor dying and leaving the car on a tow truck again, and having a big fat repair bill.

[@skylinefever]

My dad had a 1987 Hyundai Excel. It did not have this carb, but it did have some kind of carb that was connected to an O2 sensor. When the carb failed, it cost him a lot to repair it. Dad said that carb was built by Mikuni and had cheap crappy nitrophyl floats. At the time, mom had a 1985 Nissan Maxima. That car was far less reliable than the Hyundai Excel, but at least that was not where the problem was. It had EFI and did not have a problem with it. Mom had it for 9 years, and it didn't have a single problem related to EFI. As bad as the carb in the GM or Hyundai were, I heard that the absolute worst O2 sensor carbs were in Hondas. They also had the largest amount of vacuum junk attached.

[@richsarchet9762]

I lived through these being new on Denver...they were never OK. They ran with an inverse relationship between throttle opening and power until you got the secodaries open, then they might go or might backfire...either way they set the money light. TBI was like a miracle in comparison.

[@davidpowell3347]

Not calibrated to the local altitude ?

[@richsarchet9762]

@@davidpowell3347 I think that was the problem. I don't think that they could be calibrated to work well at high elevation - it seemed that the combinations of throttle angle and MAP were "out of bounds". On the secondaries they usually ran quite rich, (trailing smoke) which is typical for all carbs at high elevation. The higher you went into the mountains the worse they ran, again true for all carbs, but less of a problem for a 455 powered '70 Buick than for a 260 - 307 powered smog special.

[@GenderSkins]

I worked on those carbs when they first came out. And they was pretty easy to work on. Biggest problem I often ran into, was getting one that someone Maried up the base plate or out right cracked the base plate trying to bust out those adjustment screw caps. Those little caps on the base plate, that covered up the idle adjustment screws had to be removed in a specific way or you would damage the base plate.

[@jayinla81]

Thx for the vid. Just discovered you channel a few days ago and now this. Nice. Thx!!

[@rotaxtwin]

I wonder how much training came along when this was rolled out. If you were a young mechanic working at a GM dealership, great. If you were 45 yrs old working at an independent shop? Not so good. Around this time folk were yanking off Lean Burn computers and replacing the distributor with a conventional unit. I think there was a lot of distrust of electronic complexity, for good reason.

[@weekendgarage3299]

Very informative video! My friend had one on his 89 Firebird.

[@b_hall]

What happens when the electronics are removed or disabled? Do the metering rods stay up or stay down?

[@madmike2624]

Great content my brother, with facts to back it up, continued success !! Bravo!!!

[@Davejust451]

4:20 min, It would alter the duty cycle. The cycle time was 10 hertz.

[@capricetony]

For a daily driver and adjusted correctly I never had a problem with one.

[@AndyR1982]

Had one on an 83 olds 307. Worked great except for the choke. Pulled all the choke assembly off of it and it was fine

[@stevebot]

Choke pull offs are voodoo in temperate climates. I used to adjust mine spring and fall. F U stumble, hesitation and black smoke. There is not a carburetor in my past that I miss and the ones in my life now I would happily do without if I could. They are like finding the G spot on a quadriplegic.

[@AndyR1982]

@stevebot , it wasn't even that the pull off was bad, the car had sat so long that the butterfly pivots had frozen in the shut position. I had to remove the screws to get the choke plate off. Then I just removed the linkage so the pull off could do it's thing and allow the secondary lockout tang to move.

[@michaelm7330]

Hey, I have problem with my Buick lesabre 1984 5.0 with this carburator. Engine start well and when is cold everything is Ok. When engine is hot the car have problem with exeloration, not all cylinders are working. Its like this when I try spedup dynamic. What i should check first? Who can help? I'm from Poland, dont have shops with parts to this electronic quaterjet.

[@SkaBob]

One issue was these emissions system were a mixture of electronic and mechanical parts. The computer had no way of knowing if the mechanical the components like thermal vacuum ports, hot air choke heaters and egr valves were working or not then half the time the owners just unplugged or removed random things.... Just rip it all out it will run better.... It worked under ideal conditions but as things aged at different rates was troublesome to keep up. Throttle shaft wear would make it (or any car) idle lean or unpredictable then you could never get it properly adjusted. Lots of rubber vacuum lines and connections that got hard and broke or leaked. Going fully electronic in the mid to later 80s solved most all of these problems.

[@dave1135]

Rebuilt a ton of these as a driveability tech for gm. Really werent much different than a ordinary quadajet, just a few extra steps. Still have the specialized adjustment and service tools in my roll cab tool box somewhere

[@pauljanssen7594]

So many hundreds of these carburetors that I have rebuilt.

[@peters8758]

I dunno if I had one of these in the 2.8L 1985 Olds wagon I paid $99 for. It did have a 2-bbl carb but it was more of a gutlass than a Cutlass.

[@MrTrevorkemp]

Realistically, these carburetors were such a pain in the butt that in 1984 GM rolled out its TBI or its throttle body injection systems instead, which got away from all of the complications of this and the only maintenance that that required was a bit of throttle body cleaner every now and then. Otherwise it was a self -contained system and maybe the occasional squirt of mass air flow sensor on the intake sensor. It was a much more easy to deal with system and not only did it give you improvements in horsepower and torque. It helped to improve your fuel economy and your emissions on top of that, more than these carburetors could.

[@stevevarholy2011]

GM didn't "throw them out" because they were a "pain in the butt." They were always a stop gap measure until the electronic fuel injection systems were ready and were certified. Hence, the Iron Duke was fuel injected by 1982. The 60 degree 'sV6 were fuel injected by the 1985 Model Year. GM had to meet emissions requirements in the mean time.

[@traderdan85]

I have one on my 81 Corvette … works perfect

[@chham57]

Is there a good place to source the service manual? Great video thanks!

[@robert8995]

Had one on my '84 Delta 88 with the 307. In the last months of ownership, I would drive a few miles and then get a CEL, floor the accelerator and blow the massive amounts of black exhaust out, the CEL would go out and repeat process a few miles down the road. Took it to the shop to get looked at and was told it wasn't worth fixing. Bad transmission, worn out cam shaft and the carb issues were too much. Never found out what exactly was wrong with the carb....

[@gcaprice406]

When I was 18 starting in 2000 and for about 10 years after, I worked at a parts store. We sold rebuilt replacements of these. They were about $400. The rebuilts we sold NEVER worked right. I assume that is one of the ways these carbs got a bad reputation.

[@rporestorations]

100%

[@The_R-n-I_Guy]

This is the beginning of the end of old school do it yourself car guys. The best thing about cars with this technology is. It's easy to swap parts out to the old stuff if you want

[@shadowopsairman1583]

Pretty easy to get a carb and intake for an ls engine

[@stevebot]

Most people couldn’t fix carbs and distributors, either. Personally, I think it’s a lot easier to diagnose the fundamentals of electronic control systems than it is to diagnose the analog voodoo of springs, diaphragms and vacuum circuits. Not that I couldn’t, I was waist deep in CCC carbs back in the day and tuned many a carb on 2,3 and 4 wheelers and more.

[@JohnSmith-de2mz]

I had one in my 85 S-10 V6. I didn't like it. After about 100,000 miles it worked inconsistently, when giving full throttle sometimes it worked ok and sometimes like it wasn't fully open. I replaced it with a Weber

[@Santor-]

I liked them. Did any of them have fuel cutoff?

[@76calidude]

That is my arch enemy!! I have one in my 84 C10, and struggle with passing smog every 2 years here in California. Such a picky carb

[@shadowopsairman1583]

No california is too picky

[@JK-ed1fz]

Does it have the CCC on it because of the California emissions? Because I've never see one on a truck, but I'm on the east coast, so probably not many California emissions truck made it out he.

[@76calidude]

@@shadowopsairman1583 trust me..I know

[@76calidude]

@@JK-ed1fz yeah it does, check engine light, O2 sensor, cat, smog pump..same E4ME carb in this video. The ECU is tucked behind the glovebox. Because of California smog laws all these components have to be in good working order. Has to pass visual and tailpipe emissions test every other year or no tags. Any gas vehicle 75' or newer has to have a smog test to be registered. Diesels are a different story. If you know a guy that knows a guy you can get a "hot smog". I know a few cats that have this done..too risky. If you get popped for any reason your done all the way around.

[@johneckert1365]

​@@shadowopsairman1583RIGHT!

[@ws2664]

I have one of carbs sitting on a shelf and I'm trying to collect the tools for them. I think you had a video a while back but it wasn't really clear. I would like to see a better one, if you got nothing to do, so I can see what I'm missing.

[@pedlpower]

I find it hard to believe that everyone commenting here actually worked with these and had to get the cars running well for the customers. Especially on the high mile cars.

[@fohjimjohnson]

I love me an old Q-jet, but my dad had a 85 pickup with a 305 and one of these. It was horrible. Cruising down the road, it would just go super lean and knock like crazy. Some times it would work great, but other times it would have so little power it was hard to drive. The dealer said there was nothing wrong and the check engine light never went on. Dad finally sold it. Pity, it was a great truck other than that.

[@georgejetson3648]

305 could possibly be the worst engine ever made. Catalytic converter would fill and flatten the cam. Probably what happened to yours!😅

[@ttc5000]

I have the tools and knowledge for the pre-computer Q-jet. I tried tuning one of these computer controlled ones and it just frustrated the hell out of me - largely because I didn't have the right tools. I just don't find enough fully functional computer controlled Q-jet systems in the wild to take the time to learn them

[@Davejust451]

7:00 min, you need to punch out the plugs covering the idle jets so that you can richen up the idle by turning them abou 1/4 turn counter clockwise or more untile the engine will idle good. Apparently the factory adjusted them lean to pass emisions.

[@Alfadragon17]

My answer to your question is, if you need special tools (that are likely impossible to find by now...) to adjust a carb regardless of who mades it; it was designed to fail. It was not designed to be serviced easily. It was designed to be replaced. Look at Ford, they had the variable venturi carb, and in a vacuum they worked great! Excellent fuel economy and decent power for the time. But in reality they were replaced. Left, right and center for the same reasons. This was no different.

[@Drmcclung]

I recall these being the only domestic feedback carbs from any of the big 3 that actually worked as it was intended (performed its main function; economy and slightly better emissions in cruise conditions). CCCS on the '83 Olds 307 we had got GREAT mileage for its day, just as good of not a bit better than some of the domestic 4 bangers of the era.. up to 26hwy, but also as low as 13 if you constantly kept your foot in and out of it.. it would scoot down the passing lane just fine! It just worked Let's not talk about Chrysler's horrendous attempt that never worked right and was in production way too long! 😆 Ford abandoned theirs pretty quick and went straight to TBI and multiport as I recall, whatever it was they were utilizing for electronic carbs wasn't around long at all

[@workingcountry1776]

Ford had MPFI when B body gm had carbs still took til 1994 to get MPFI with GM and it wad the junky optispark lt1 engine

[@Drmcclung]

@@workingcountry1776 now I'm going nuts trying to remember what Ford called their feedback carb system. I only ever remember seeing it a handful of times ever, in a very early Tempo and I think one more 5ime in an early 4banger Taurus. And you're right it took GM ages to catch up to Ford on EFI reliability

[@johneckert1365]

​@Drmcclung Are you talking about that wonky Variable Venturi carb from the early 80's?

[@stevebot]

@@workingcountry1776 Meanwhile every other GM car had some kind of FI, many of which never got noticed because they just work, kind of like GM HEI which apparently refuses to die while Frod TFI (both kinds) have long since died and Chrysler’s EI is…. well… LOL, wut?

[@Drmcclung]

@@johneckert1365 nah it was nothing like that, although I think I know the one you're talking about.. if it's what I think you're thinking of, original Bigfoot ran those and can't remember what their name either. It looked absolutely nothing like a fuel delivery device 😆 I remember something about dialing in afr with cams that were on the linkage. That's a blast from the past

[@mikeypoo2211]

Great video! I have one of these electronic quadrajets on my 87 Caprice cop car with the 350. Anyone know where I can get a fuel line for where it runs into the carb? Broke mine swapping the fuel filter out. Also need the insert part for the filter that goes into the carb. Any help would be appreciated .

[@hugieflhr03]

I remember the old Cadillac quadrajet had the automatic altitude control and this carb changed that to electronic

[@alanchan1772]

I use to rebuilt g.m. carb,set up.throttle shaft wear out bushings the shaft set up per g.m. specs

[@billmalec]

My '75 Opel had fuel injection. Never replaced any part of the fueling system. Always worked perfectly. Oddly, it had points however... Go figure.

[@skylinefever]

EFI was the one thing that made smog engines work.

[@graymodeler]

I had a new 84 Camaro and the solenoid failed. Car ran crazy until dealer fixed it.

[@itseithergonnaworkoritaint7852]

I think they would be way cooler if there was modern software available to be able to customize the fuel curve. Also the old 80s electronics are getting ready to fail any day now and to keep them running it's going to eventually need something. Other than that I think they would be kinda fun to play with.😎👍

[@volks-jager]

i dont know how many of these i threw in the trash back in the day and swapped on regular Q-jets... nobody knew how to mess with these.

[@donames6941]

2 things in this world that hard to fix and adjust, and that's Qjet and a woman .Got the Qjet working great. i am 70 years old and still trying to figure out the woman.

[@zeno15sti33]

😊 Dang where were you when I was like 17

[@ckratzet5286]

m/c solenoid had the lean limit adjustment It way way more adaptive than you speak.

[@whirlpool1978]

Quadrajet carburetors-when you get a good one-they can be one of the best carburetors you can get-but when you get a bad one-they can be one of the most aggravating carburetors you can get-when they are bad, they are junk.

[@pedlpower]

I hated these! And just looking at all those vacuum hoses brings back nightmares!

[@olikat8]

My '88 Gran Fury cop car has this style feed-back Q-jet, but it will be going away when the (very crude) ECU ignition gets thrown into the trash. Have to replace the intake, carb, and ignition with a more-tradition set up. Ages poorly, parts are non-existence and the car is not going to be re-done to stock specs.

[@rporestorations]

I've never owned a Chrysler with the Lean Burn System, but I've heard horror stories.

[@olikat8]

Its better to just get rid of it​@rporestorations

[@skylinefever]

@@rporestorations My dad owned one. It made him want to use Lee Iaccoca's grave for a urinal.

[@JDARJISJ]

I suspect this what was on the Celebrity 2.8V6 I drove in college. The car was a low mileage piece of garbage that was a basket case of problems- except for the engine which didn’t have any problems aside from being gutless and poorly designed for maintenance.

[@LewisBX]

I have t misfortune of living in CA. Where you can not change Anything about t wheels you drive if it is under AQMD regs. I have an 86 Chevy. Van w/305 and it's a problem. I can get it smogged but it's WAY to much trouble to get a TBI to work. I will soon leave this once beautiful state for greener pastures and then I can get an RV cam, dual exhaust w/headers and a 79 Carter carb. By t way you can make an engine get best emissions Or best fuel milage. Bu[ not both, as I am on soc. Security, I must have better milage. And that's the way it is.

[@Sheisthedevilyouknowwho-ft9we]

Well said. I live in a state that has never tested our cars. The 1970s catalytic converters would plug after a few years. Car kept dying, wouldn't run. My dad would take them off. Luckily it didn't matter here

[@antoniovillanueva308]

YT blocked my comment. I think I might have said something offensive about that carb setup. I am sorry, I had no idea that electronic Quadrajets were so easily offended.

[@BlackPill-pu4vi]

This is a common problem. 90% of the algo is geared to protect one very special demographic. Even the emojis for them will alert it. The other 10% looks for too much technical detail, an active voice, and a Flesch-Kincaid readability test. On the last, if a cmmoent scores too high, it gets dumped. You got caught by the 10% part.

[@Sheisthedevilyouknowwho-ft9we]

You mean he called the Quadrajet a rump ranger, an ass pirate, a Hershey highwayman, a pillow-biter. ? 😂

[@schizy]

That electronic carb was the forerunner to the Cadillac 4-6-8 engine in wisdom.

[@TeeroyHammermill]

V864 sole purpose was to save gas. E-Carb was to reduce emissions.

[@johneckert1365]

​@@TeeroyHammermillright on 👍

[@TozziWelding]

Remove and replace with an Edelbrock carb and an MSD ignition

[@mcqueenfanman]

I don't know why they wasted their time with these. It has most of the same components as a tbi system and in some cases these had both a mechanical and electronic fuel pump. Both the systems had map, coolant temp, throttle position, o2 sensors, and an ecm. The carb had a mixture control solenoid instead of a pair of injectors. Both had ignition timing controls too. Similar air cleaners and intake manifolds as well. When the feedback carbs had issues, they ran very badly.

[@Oldbmwr100rs]

GM is well known for wasting millions of dollars to try to cheap out on their cars, and leaving the problems to the consumers and dealers. You're right in that TBI would have been a far better system and they had more than enough technology at the time to put it on everything.Think of how good that would have put them in the market too, and the TBI system was pretty easy and reliable right off. GM is the same company that had their Opel division rebuild an in production 4 speed manual into a 3 speed just to make the Vega that much crappier to those cheapskates who wanted a base model. They lost money doing that, but hey, they punished consumers, so that was fine.

[@johneckert1365]

​@Oldbmwr100rs It's amazing that GM kept using carburetors on the Olds 307 through 1990. WTF?!?!.

[@mcqueenfanman]

@@johneckert1365 There's a guy on the Olds forum that has a factory one off TBI intake for a 307. Must have grown legs and walked out of the test center and wound up on e bay.

[@johneckert1365]

@@mcqueenfanman Someone brought a BIG lunchbox to work that day 🤣🤣🤣

[@johneckert1365]

So dumb, since the technology already existed at GM. Didn't Caddy offer TBI on their 500 in 76? And on their 425 for 77-79? By 82 thier TBI worked very well on the awful 4.1, it sure seems like many more of thier vehicles could've and should've gone TBI that early as well. I don't understand thier logic I guess 🤷‍♂️

[@CreateAnduseSystem]

Flashbacks aghjj

[@rogermoore8977]

Flip the air cleaner lid over for 10 extra horsepower.

[@ddyeo503]

It was easier to just find an older GM car no longer running, and put an earlier quadrajet and distributor on the engine. Then there would be no more nonsense of the problems that these carburetors had. Mechanical Quadrajets were a good carburetor and once you tore them apart occasionally to clean and learned how to do it, they would run great. But the worthless fuel filters they had, some dirt would always get through them,,,,,,,,,,,,,,,,

[@nicolassanchez8318]

Not a fan…I would try to rebuild another one but I prefer fuel injection

[@williamjames5624]

Find you Qjet rebuilder who knows them. And there’s nothing better

[@TeeroyHammermill]

These ran like any other carburetor. Your engine had to be healthy for them to work right.

[@shadowopsairman1583]

Even efi the engine has to be healthy, no compression, good luck.

[@TeeroyHammermill]

@@shadowopsairman1583 : True but the EFI engines would try to compensate for general engine wear among other things which resulted in them running better longer. These carbs were hellbent on keeping things lean so when the engine started wearing out and emissions devices started failing, you'd get rough idling, hard starting, occasional stalling. Them engines with the VaraJet would start acting up with 40k or 50k miles on them.

[@davidpowell3347]

@@TeeroyHammermill As I remember it was possible to make the solenoid keep the metering rod at the rich end of the travel all of the time,that made the engine run extra nice/smooth but if left that way for any length of time I believe the gas mileage would go down and the catalytic converter overheat or otherwise wear out. On the version used on the Chevrolet Citation V6 making it run rich would sometimes mask a performance problem actually being caused by weak spark due to a bad ignition module. I believe that with those cars "XII H.O. 660" you needed to substitute a known good ignition module before condemning and diving into the carburetor. There may have been a couple hidden under bronze adjustment screws that could be messed with by the adventurous in order to soup up the car, especially if the cat converter were "missing" . One set the leanest mixture when the solenoid controlled metering rod was "down" the other set the richest mixture when the metering rod was "up" .

[@markfierke8565]

The worst carb on the worst engine, the 307 olds motor

[@bensfixitpage341]

Great information

[@rporestorations]

Thanks!

[@cuda6496]

I would put it in the garage And use a Holley carburetor !! 🤷‍♂️

[@gcaprice406]

When I was 18 starting in 2000 and for about 10 years after, I worked at a parts store. We sold rebuilt replacements of these. They were about $400. The rebuilts we sold NEVER worked right. I assume that is one of the ways these carbs got a bad reputation.

[@rporestorations]

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