94 Chevy 3500 454 TBI Replacement Issues!!

[@BarnacleBillOrigin]

Randy, You need to slow down a bit. Your truck is not junk, youre just out of your comfort zone with it. As a GM tech from that era I can tell you a few things. Hydroboost is an excellent system. Only has issues with the accumulator if you only have 1 pedal pump before losing assist. Easy to fix if needed. As far as the driveability, Im not surprised the aftermarket rebuilt unit is goofed up. I would put the old unit back on if the throttle shaft is good and just change the bad injector. Otherwise you could screw around with this one for quite a bit. See if it idles on carb spray. If so you have either a vacuum leak or the injectors are not correct for your application. There should be an 8 digit number stamped on the old TBI to ID it just like a carburator number did in the day. You may need to reset the minimum air bypass for proper minimum idle speed but it shouldnt effect on road running. I think you have the wrong (or bad) injectors in the reman tbi. Rock auto has complete TBI assembly listed for $280.00. They also have AC Delco injectors separately.

[@Apolloneek]

Any recommendation on the tbi injector wires mine got fried and I'm wondering if rewiring it is smart or getting a new tbi unit because the injector is leaky also may be better

[@derrickodyes1934]

has a vaccum leak is why its stalling i can hear it from here. Check base plate gasket, egr valve, intake gasket ect. propane enrichment works good or smoke test

[@resurrectionautorebuilders8465]

I’m watching the video yelling at the screen the he has a vacuum leak and lo and behold, first comment I read...... LOL!

[@davidbuck9977]

with the air cleaner off it will sound like a vacuum leak just from the air rushing into the IAC port and the holes in the throttle blades. My thought is he ordered the wrong throttle body all other TBI were ~13psi of fuel pressure however 94-95 454 TBI were 30PSI

[@missingremote4388]

@@davidbuck9977 I have the same engine. 1995 GMC 454. Runs good, idles high 1000+ RPMs. I'll be swapping in a new IAC valve tomorrow. If that doesn't bring it down to 500-750, it will need to have TBI service.

[@toppledgod]

I suspect that is not the problem. Watch the throttle link as it's spluttering, a vacuum leak will become less of an issue as the engine revs. It won't rev. I suspect fuel starvation, possible fuel pump/system problem. I also question Randy's logic that a short circuit in the wires caused a fuel injector to short, after all if there was a short in the wire the current wouldn't even make it to the injectors: logic fail! A distinct possibility if there was a short circuit in the wires is computer driver damage...

[@slawkowegrzyn2115]

I agree with you it is a vacuum leak or the vacuum ports are not right for the engine.

[@Anthony-ho4kw]

I say keep the truck. It can't be a big issue to get it fixed. It will do the job and you can focus on making that money back.

[@pbattis1]

it does not matter whether the truck is a good buy or not. . .its whether the content is good. . . .and it is. So we learn about throttle bodies and diagnosing them. That's fantastic. Actually. . .the worse deals you do. . .the better the content for us. Best channel on KZbin.

[@Twisted_Harlock]

Hope you get it working, nothing feels worse then getting screwed, in the end I am sure it will work out. Stay safe.

[@jayz4evr]

Than*

[@reponut12345]

Buying used vehicles can be a crap shoot, Only so much you can look at

[@2008equinox]

Leave it outside the shop, hopefully it will get stolen.

[@frankm6601]

That's hilarious, he needs a new line of work preferably non mechanical.

[@45AMT]

Don't forget to leave the keys in it.

[@alenabyndyu9624]

Even if the keys are in the truck they won't steal it. It don't run. Unless they tow it to scrap metal

[@cincyspin178]

@@frankm6601 I'll second that...LOl...

[@marthasmadman]

At least it isn’t an 87 first year of tbi oddball because it’s the last year for square body on the pickups it did carry on to 91 on crew cab and suburban

[@latrogeniwile58]

I own one of these. K2500 Sub. You probably need a MAP sensor. And you need a fuel pump every 80K miles. Fuel filter every 10K to 20K miles. I've changed the entire fuel system and entire ignition system and it runs like a beast. I used the fuel pump assy from the '96 Vortec, a direct fit with better flow. Also check that your Oil Pressure sender isn't blown. Also make sure the set-timing connector is not corroded.

[@philjaneiro1638]

Those are all small problems.. When you put it all together it gets big... But on their own..there small. Adresse it one at a time.. It will be a great truck.

[@MrJoebiz24]

The good old Crocodile Dundee brown leather jacket. The ultimate service uniform for a certified tech replacing a "dad gum thing", and dang small O rings. (Sorry Randy, trying to add a little levity to a stressful situation). Please keep plugging!

[@dougsmith4879]

My 88 454 TBI wire to the injector broke once while putting on the air cleaner. I carefully set it back on the injector with no glue and it runs fine!

[@Mr19853]

Dude you are bleeding money from way too many holes!

[@chapmaker46]

yea ive already told him that,,,,

[@rubencamacho2444]

Sounds like a vacuum leak and the issue with the headlights is the multifunction switch

[@aleksandrnathanevans]

Ruben Camacho I wonder if he transferred the cap from the capped off port on the old tbi unit.

[@sammyspeed9733]

your a good dude, with a good heart. people make mistakes, but that is how you learn. Unfortunately you have been hit with a ton recently, but I guarantee you will not do them again anytime soon. I will keep you in my prayers.

[@skidsolo8140]

It's not bad luck you keep having man, it's incompetence.

[@RickConley]

I feel for you ..... Last year, I bought a used $6,500 car and got a great deal on it at $3,600. Since then, I have put over $5,500 into it. It is great to drive and I'm glad because I have to keep it to drive now that I am this far upside down.

[@legendsofcaraudiobradnewso8424]

You already invested the money in it, why lose money to flip it when you can just finish it and use it. Make it YOUR truck and do all the little things to personalize it to your liking and then enjoy it. We have all had that moment when we impulse buy, make the most of it and fix it. I guarantee once you figure out the true issue and get it running good, you will love it.

[@shanemc5136]

The one question I have to ask is, why he paid so much money for such an old truck? that truck worth the most &650

[@legendsofcaraudiobradnewso8424]

shane mc good point, but I have paid up for something I wanted as well. I look at it like this, time and money will make that truck exactly like he wants it. Just got to want to make it happen

[@malibuss66]

on our next episode of Auto Auction Rebuilts i bought a 3500 dually diesel for 2200$ on marketplace and the white 3500 454 tbi is for sale!! just pulling your chaines Randy ...maybe look at body ground sometimes they get rotten, keep up the good work and hope you get it fix!

[@ddurf4726]

Randy, they put the hydra booster system on diesel equipped trucks ( you said it was a 6.5l diesel before) as a diesel does not have any vacuum to run a normal brake power booster unit. Diesel engines usually add a vacuum pump to run small items, but can't run larger demanding vacuum boost units.

[@gac914]

Poor Randy. . . . it's like watching a daytime Soap Opera. . . .!! :-(

[@garyeverly574]

Hey Randy don't lose much sleep over that truck I've been a mechanic from 1980 till now that tbi units are pain first thing I'd look at is to see if you have a vacuum leaks on the unit and the lines on the head lights just replace the headlight switch the breaker unit in it getting weak buddy keep you head up your doing fine

[@ebayer1980]

And Silverado wasn;t good enough for towing, that You needed this one???

[@firstonraceday7865]

went from bad to worse need a ford

[@LiamDoesTech]

@@firstonraceday7865 bruh

[@Unknown-vm8ri]

@@firstonraceday7865 ford is a trash can

[@firstonraceday7865]

@@Unknown-vm8ri compared to what your broke down dodge

[@Unknown-vm8ri]

@@firstonraceday7865 yet my dodge is a 2.7l with 234k

[@q135980]

You really need to grab a factory service manual set (physical or digital) for this truck off eBay. Then you will find clarity in the darkness of pre OBD2 diagnostics, as well as the other systems in your truck. Strangers on the internet will never replace the very important information contained in the FSM set. I think you can do this, you just need the right information💯

[@druffner3074]

Oh and headlights... dimmer switch or relay over heating and tripping?

[@dale7436]

Such a good running comment on “How To”, very informative. It’s good that you talked it through for those that did not know. It just happened the way it did with the vacuum leaks. Still an easy fix, video well done Randy.

[@RedRiverRedNeck309]

Had the hydroboost on my truck and loved it, wait until your loaded and you will see how well it all works.

[@thefilmguy]

My dad has a 99 K2500 Suburban with the hydro boost system. It's got multiport injection and OBD2 on its 454.😁

[@mjdoug44]

That 6.5 is great when it’s running, you let that tear up and your talking big $$$$$$ my 1992 dually 454 is missing up like that, I’m not giving up, I’m still working through the problem

[@jimfrese7579]

Randy don’t give up. You’ve been in a slump for a few weeks but I’m sure you’re about ready to start a winning streak.

[@paulfunk1818]

When dealing with an engine swap I would look for loose or disconnected ground wires. When doing an idle relearn always turn on as many electrical loads as possible. The block should be stamped by the water pump with letters and numbers that tell what year it is. I would check the headlight switch and especially the connector and also the fuse box for signs of overheating or corrosion.

[@Kapnez]

ya .. way better than my ideas

[@jamesparker6017]

Hello from Melbourne Beach Florida 🌴 I s-it caned that nonsense on my 88 GMC dually &new Edlebrock. Runs great!

[@rolledz24]

Randy , I replaced my injectors on my 95 . Then I had a professional mechanic flash the computer with his 5000.00 tool . It ran like new after that.

[@billmeredith6203]

I had the same issue on a 95 G20 van with what looks to be same throttle body. It sat for a year with little fuel in it and there is a small rubber hose on the fuel pump that if left out of fuel for a while will crack and it is like trying to drink through a split straw. 1.00 worth of new hose fixed the issue. To test you want to make sure you have proper fuel pressure. T in a gauge on your supply line and make sure you have proper pressure to the TBI. From memory it was like only 12 psi and I only had 5 . Hope this helps!!

[@johnb.7979]

I wonder if a sensor downstream got fried when you pinched the wires?

[@ddurf4726]

I am thinking it might be a broken wire inside of the insulation where it got pinched, use an ohm meter to check that the wires are good. GOOD LUCK

[@classicclinic]

Call Identifix hotline. They have ASE certified mechanics specifically for each (domestic, Asian and European ) and specialist within those. I use it all the time and it helps pinpoint the problem instead of throwing parts at it. The first call is only $39 if you have to call back it’s $20 something , 3rd call is roughly $10 and the phone calls thereafter are free for the same issue. They will give me a punch list of what to look for/ check out and I can usually pinpoint it with the first call. Well worth the Money. You don’t want to try and figure out these problem child’s on your own and throwing parts at it sure gets expensive. It’s a cheap education and gets you onto the next project. Been a sub since the Uber days and like your what your doing. Best of luck Randy

[@mattpamp8204]

Both tbi unit have the air horn milled&the injector spacer can't tell if bores have been honed they changed the screw heads to button top

[@lylebrock3550]

Randy , their should be a engine number stamped on the block that would have a date code ,I think its on the block just below the left cylender head facing the front of the engine .

[@joedorcas]

I have seen those HYDRA BOOST systems too many times. Even the older CHEVROLET/GMC Class C motorhomes have it. MAINLY used on the DIESEL system.

[@97HarleyD]

I have the hydro boost brakes on my 04 Suburban with the 6.0

[@Garth2011]

Used on vehicles that usually will not have a lot of intake manifold vacuum such as trucks that are 3/4 ton and up.

[@iskydivetoooo]

Randy, for your headlights, check the ground wires under the hood, and tighten the ground bolts. Had the same problem with my truck. I'm not talking about the big ground wires. I'm talking about small ground wires that are about 18 awg, and are located near the front radiator support. Cost me over $2k to fix that intermittent problem. It's an old GM mechanic that finally found the problem.

[@dan5979]

my new favorite trainwreck channel

[@mritron7649]

They used different size injectors for 94 and 95 because the fuel pressure was increased from 13 psi to 30 psi.

[@williamsinger4124]

Thank you...get crazy with the cheez whiz... now that Beck song is stuck in my head. Great video Randy

[@thetruthwillout3347]

I got that too! "I'm a loser baby so why don't you kill me"!

[@williamsinger4124]

@@thetruthwillout3347 at least it's a good song lol

[@buddylight2191]

Maybe the pinched wire has messed something electrical up? Head light switch usually has a circuit breaker in it that causes the on and off as it over heats and cools the weak circuit breaker.

[@aicsusa]

Hydro boost is better than the vacuum assist! DO NOT REMOVE IT! Glad to hear you came to your senses about the purchase of the truck! OK, we told you so! Now lets get it fixed! RETURN THE DEFECTIVE $550 TBI unit and get your money back! Just get the rebuilt injectors on your old one yourself! Also check the ECU! The computers on these truck work very quick normally! Replace the headlight switch! It is common they go bad! DUMP IT!

[@1chish]

You are an open and genuine guy Randy. Respect from the other side of the Pond mate. Now if you pinched those wires and they are driven by an ECU of some sort then its quite possible either a sensor is burned out or the ECU needs resetting. Certainly worth checking the fault codes if you have the right connector and clearing them. The fact it won't idle points me in this direction as a point from which to start. I am not sure pinching those wires burns out the actual injectors rather the sensors further back in the system after all you now have new ones in and they are not firing (or have no fuel feed of course). Also check those wires to the two connectors on the side and see where they go or what happens if you disconnect them? And if you find some wiring / ECU / sensor faults then use the original and try and get a refund on the new one. Good luck mate ... Best of ...

[@joehomanick]

Hey randy I’m thinking the driver in the computer shorted out when the wire touched. Send that throttle body back fix yours

[@ACHAutomotive]

Joseph Homanick fully agree - My dad picked up a caravan that had a similar issue. My dad is an electronics tech and found the driver was blown in the ECU. Replaced it and fixed it.

[@brandonvansel3716]

The o2 sensors or the cat is clogged up.check the wiring first and also use some wd40 around the base gasket.start it and see if juicing the wd at the base of the tbi will cause an idoe difference.worst case a carb will work even with a 4l60 if you use the Holley tps sensor.Even easier if you have the 700r4

[@mattpamp8204]

2inch bore 454 have there own injector make sure you didnt get a small block unit

[@j0gigs]

I had a similar problem with an 84 Eldorado that has a similar throttle body FI setup. I pinched one of the fuel injector wires and it blew a fuse for one of the injectors. On my car, there were 2 3 amp fuses under the dash. One for each injector. I replaced the blown fuse and all was fixed. You should be able to look at each injector while its idling and be able to see the fuel spraying into the throttle body. I hope this helps you.

[@gosportjamie]

The stalling issue sounds very much like a failed engine temperature sensor so the fuel injection isn't getting a signal to boost the fuel and engine revs when it's cold. Like a vehicle with a carb, when it's cold it won't run without the choke on. You're just lacking cold fast idle control, it's just a case of tracking down which engine temperature sensor is the relevant item and replacing it with a good-quality item and it'll be fine. The running issue is simply that the electronic control is learning its parameters again to suit your driving style, this is a very common thing with '80s/'90s fuel injection vehicles, the VW Golf GTI mk2 with the Digifant injection does exactly the same thing. The headlights issue sounds like something in the circuit is overheating and switching out until it cools down, I would guess a relay or switch...

[@snisneves2894]

Great video Randy! Hope your doing well, and keep making such great videos!

[@mikeycraig7138]

My 81 1-ton has hydro boost it’s great the one tons had them because of the big breaks

[@entropyfan5714]

Fix it & keep it. For work only; this is not a vehicle to just daily; it's for towing, getting big heavy stuff, etc. Any one of the trucks you have purchased on this channel would be adequate for this purpose. BTW, when the dually was running, sounded awfully lot like a vacuum leak, so maybe do the old squirt soapy water trick around the base & ports to see if you're leaking anywhere.

[@CR7659]

1. change the MAP sensor. My '88 G20 ran like a dog when I got it, even after changing the O2 sensor that was broken in half that I discovered on the way home from buying it. I swapped that sensor out with one off the '91 and it solved the problem. It wasn't giving me any codes, it just didn't want to run. 2. Did you check for codes regardless of any CEL indication? 3. Check fuel pressure, consider a fuel filter, they're not expensive. Pressure should be around 14. 4. Consider downloading an OBD-1 specific software program such as WinALDL and making or buying the cable to use to connect to the truck. WinALDL will run on a fairly old laptop (the one I bought Saturday for $35 is more than enough) and will give you a lot more data than just codes. A good video with a diagnostic program, going through all that for OBD-1, should generate views and thus income and make up for some of the loss on it. Which at this point is how you need to look at this truck. How can you generate three or four grand worth of content from it? A TBI is normally stupid reliable because it's a simple system. Whatever is wrong is probably also simple. It's just a matter of diagnosing it. This stuff happens to all of us, the first 2002 van I bought I thought I did okay on at $650. Four days later it won't start, then starts but stalls in gear, gauges going up and down acting crazy. Turned out to have a hole corroded in the computer case and when it rained after I got it home it got water in it. I had no means to fix that, so $1200 later at a garage we got that fixed. And then the garage F'ed me by not even looking at the power steering pump, only to bang me on a little leak for the state inspection. But they did give me some free wiper blades. Anyways, it's not the end of the world.

[@CR7659]

Also, if you didn't already, check those wires to the injectors, put some tape on them.

[@molnstv]

My name is Steve I'm using my wife's account I've been a mechanic for almost 20 years and I've worked on several of those trucks with simular issues you need to have someone start the truck while you watch the injectors spray see if they are both working hold it at a fast idle and see if one stops spraying these trucks are known to have computer issues when it comes to the injectors what happens is one injector will stop working all together or work intermittently the remedy is to replace the computer it is very easy to replace it's on the passenger side behind the glove box or under the passenger side dashboard if I remember correctly it's been about 5 years since I changed one I would go to the junk yard and get a used one it can come out of a bunch of different vehicles as long as it's throttle body injected like yours I've taken computers out of a v6 s10 and put it in a full size v8 truck and it worked fine I'm sure the junk yard is littered with them I actually have one in my garage but I'm in pennsylvania so that won't help but if I was closer I would give it to you if you have any questions ask me I'm sure you can get it running and it's not gonna be a big issue

[@Garth2011]

What year and make vehicle did that computer come out of? Still have it? Want to sell it?

[@adamwidmeyer]

I have a 1994 Winnebago with a 454, It would idle rough and almost die when put in gear. I changed the temp sensor since plugs, cap, wires were recently done before I purchased it and the issue went away for a little bit then came back. It would idle with a slight tapping, then almost die, then roar back sounding smooth with all the power. I changed the TPS sensor since the symptoms are the same but no change so was about to change EGR. Anyhow I remember this comment and had to go back and find it, sure enough only one injector is spraying, I remember seeing them both spray before so it's intermittent. I thought it was bad fuel at first but that didn't pan out. Looking for a new computer now, thanks for your help!!! It seems like this has boggled so many others, this info is gold...and the intermittent part just adds confusion so thank you so much

[@brownlee62534]

Randy, first of all I've been where your at and it sucks. I chased a really similar problem for a month. When an old drag racer l knew told me to check the fuel supply line between the tank and the steel line going forward. I had replaced the carb, the cam, the distribution, Coil,plug wires, cap, rotor and begged GOD to make it run right. I put 3" of fuel hose for a buck and it ran like a top. I nearly burned it l was so pissed. The other deal like yours turned out to be a grind problem. Like your truck someone had changed the motor and decided all the ground wires weren't needed so they just hooked up a couple. 12 volt hates lack of grounds. Your truck is new enough to be highly electrical sensitive. I finally had an auto electric guy look at my problem on the truck, he spent fifteen minutes on it reconnected the grounds Cooter didn't need and bingo my truck ran great. Best $75. I every spent. Everyone telling you to keep the truck is right. That is a mega bad ass truck. I've owned a few. If you fix it you can drive your money out of it. Run like a deer from that old diesel. I ate that turd once real hard. Once that truck runs right you will love it. My race car partner bought one l built a Holley 650 mechanical secondary for. Went from 10MPG TO 16MPG and ran like a champ. Keep the truck. You don't need to bleed any more money right now. It's a great truck.

[@hedatguy]

Don't worry about what people are saying. You are putting out good content. Keep it up!!!!!!

[@IrocinZ]

I would look at the coolant temp sensor for the ecm. It's a two wire sensor with a yellow and black wire. They were notorious for failures. It will -40 and still run but will stall...

[@mikefloyd6732]

the ECT sensor on TBI systems control everything...it controls timing,fuel control,idle control......FYI on that system the base timing is for 400RPM and less so adjusting timing does nothing for you...the ECU takes over timing control at over 400 rpm

[@jf4872]

@@mikefloyd6732 Agree. The cooling temp sender at the front of the intake manifold will also incl. (2) wires mounted to a grounding bracket (curved) to the T stat. As for idle on my 94 TBI in my Fleetwood RV the idle RPM is roughly 700-750. Also if the ICM is not working the injectors will not either. But the fact that you can get it to run when working the throttle suggests they are working. Until you let it idle then it dies. I say it's either the cooling temp sender or ECM issue.

[@MrTydriver]

Hydro-boost is VERY common on larger vehicles such as 3/4 ton trucks and up. It gives you a boost to your brakes that normal vacuum brakes cannot. It is definitely a great invention when you understand what it does and how well it performs over the stock vacuum design. If you have bad brakes for whatever reason, it isn't because it has hydro-boost on it. I should also mention, you may have shorted out the "injector driver(s)" in the ECU if you shorted the wiring out by pinching them with the air cleaner. They send a signal from the ECU to the individual drivers at the throttle body. When this happens it may only be running on one of the two injectors. Take a look when you start it up, you should be able to put a NOID light on the connections for the driver that will tell you if the wiring is receiving a signal from the ECU to open/close as needed. You should also see a cone shaped fan spray from the injector when its firing fuel.

[@pugsbella]

just a suggestion get a noid light and make sure you are getting good injector pulses to each injector, it could have damaged the module when the wires shorted out.

[@immrfixit1260]

Randy check fuel pressure may be the problem on highways. You also need set base idle. Good luck

[@ramfrancisuk]

It is not that bad. You can fix it. I am sure

[@chrisgentile3530]

I have chased dragons like this on a Chrysler TBI system. The car would chug, buck, idle poorly, stall at lights and so on. It would also drink gas like you would not believe. Just like your truck there was no code or check engine light. TBI with map sensors (at least with Chrysler’s) use a speed density system where the fuel mixture is controlled by a single o2 sensor. It uses the open loop mixture programmed in the computer for cold start and WOT. From what you are describing it sounds like your running really rich. Unplug the o2 sensor and force the engine to run in open loop. See if it gets better. The idling issue could also be a bad IAC. I have had them bad out of the box. Usually a bad map sensor sets codes.

[@guod1973]

Hydroboost units are found on Diesel trucks (with hydraulic brakes) due to the fact diesel engines inherently dont make vacuum.

[@chrisj197438]

Douglas Chaney They are found on gas trucks as well. I’ve had an Astro van and a full size van with the hydroboost set up.

[@WhiteArmaRS]

Randy, after messing up and overpaying for this truck. You should run this truck as long as possible. You already lost money when you overpaid. Be more careful in the future so you don't do the same mistake. Keep up the builds! :)

[@dwightbrown4647]

Have you tried replacing fuel line filter under truck that will cause the problem you are having

[@KevinJohnson-fx6wq]

Yeah, such is life Randy. Maybe you can find the engine # and trace what year it is. All I can say is take it what one step at a time and hope for the best. Thanks for sharing.

[@Oklawolf]

My first two cars were 1979 Lincoln Continentals - they had hydroboost on the brakes. Never had any issues with the system on either. Kind of gave the brake pedal a nice smooth feel compared to the vacuum boosted cars I knew at the time.

[@gosportjamie]

Hydraboost is a pretty common system on the US on larger diesel vehicles. Petrol/gas vehicles use a brake servo/vacuum booster because those engines produce plenty of vacuum to run them. Diesel engines don't produce much in the way of vacuum so to run a vacuum booster the vehicle would require a vacuum pump to run, which would introduce and extra part that could fail. So an easier option is to use this type of set-up where the pressure in the power steering system, which is there constantly as the pump runs all the time the engine is running, to provide boost for the brakes. It's a logical step as pretty much all diesel vehicles, especially larger ones, have had power-assisted steering since the 1960s as standard equipment with diesel engines being a lot heavier than petrol/gas engines...

[@wandajames6234]

Hydro boost is more efficient than the old massive boosters-- just borrowing some extra boost from the steering system -- good for heavier vehicles that take stronger braking to stop the momentum of all that weight. Retired Class A tech here.

[@Lilmiket1000]

I love the hydraboost system. Its very compact and easy to understand. And anytime anything goes wrong you know what it is because you lose both power steering and brakes. Its also pretty reliable. But my biggest like is that its compact.

[@rodolfgermany7461]

Did you fix this truck, I have same problem with GMC 3500 93 7.4 454 if you fixed tell me how??

[@WH6FQE]

I am working on a very similar TBI issue with a 1990 Chevy K3500 Extended Cab 4x4 Dually with an 8 foot bed that I purchased for $5,000 that only had 34,000 original miles on it. I have had to replace everything from the fuel tank all the way up to the TBI so far, but when a friend replaced the TBI sensor, he ended up breaking the bold off in the TBI so we had to temporarily modify it to work. I am looking for a replacement TBI now and would like to do a complete swap like you did if I can find a full TBI setup for it. Most of the idling issue has been taken care of now, but I can tell the timing of the injectors is not quite right, so hopefully if I swap the whole thing out that will take care of that issue once and for all.

[@DillonMcadams]

Take a can of ether to the mating surfaces, intake to head. Bet it’s intake gaskets

[@Markw1063]

If I remember right there is an adjustment screw for the idle even though it have that idle control there should be an adjustment screw

[@larrytrevino7002]

You need to do a idle air control relearn and possibly a TPS relearn

[@Garth2011]

Agreed

[@eljefe620ify]

Got it!! Torque specs a “little over snug” lmao that was funny

[@midnightgambler3718]

Sounds like a vacuum leak. Hydro boosts are generally on diesel powered trucks. I'm glad you admit that truck was an unwise purchase, considering you had other trucks

[@keithyoung5709]

Hydro boost are on pretty much all 90's GM trucks.

[@johnguerard1355]

Honestly Randy the truck has good bones. Fix her make her yours. Once you have it running update the rest of the interior, she'll be exactly what you needed and wanted.

[@darkknight1980ad]

My 1975 Lincoln town coupe has hydra boost . It provides extra braking power on heavy applications where a standard brake booster wont cut it.

[@blazinbrent]

My dad's 92 one ton had that headlight issue, it was the switch. An after market alarm was terribly spliced into it by me when I was 16, I jacked up the switch. New switch fixes it. It would get hot and stop working after 10 to 15 minutes, shut off for 5 to 10 mins and then come back on...repeat. hopefully that helps ya Randy...if it does give my KZbin a shout out...street legal 520...I don't do much but I have fun.

[@CVO_GUY]

Get Mike on speed dial for approval on any car or car item purchase over $100.00. You'll save yourself a lot of aggravation and money. LOL

[@nevets68]

RANDY - I want to purchase this Hot Wheels car for $2.00. MIKE - I approve of that purchase. ;)

[@fallon55]

Fix it. Keep it. As others have said - the stalling is likely a vacuum leak. The lights are the probably the dimmer switch or the main headlight switch. Drives you crazy until you find the source. Oder GM products (before the multi-function switch) it was almost always the dash switch. On rare occasions it was the power relay to the lights.

[@ddurf4726]

You need the ECU to learn the throttle position sender, sometimes you can drive it while it learns, and sometimes you turn ignition on (not running) and slowly fully cycle the throttle 5 times, then start it up and see if that helped.

[@rafaelcervantes5490]

Keep the truck at this point man just think about as a great video content for the channel. Get the best out of the worst. We learn from our mistakes but make the best out of it 😉👍

[@IrocinZ]

The headlight problem is more than likely a dimmer switch. Part of the turn signal switch...also common...

[@jonredd650]

Headlight fluid is probably low. I'd check the easy stuff first.

[@Garth2011]

Want to sell that GM TBI ? All you needed at first was a replacement right injector or both of them and they are available from GM still. Also, since those injector wires are "fixed" with electrical tape I would also buy new FI Pig Tails that are available which will splice/connect closer to the intake manifold area vs. up above the TBI casting. Use butt connectors that solder/crimp and have a sealant inside them to prevent oxidation etc. Did that short cause a problem with the PROM? Best way to find out is to buy one injector and install the original TBI unit back on and see if it runs the same. Those IAC valves also have to be calibrated to the computer and "base idle speed" via the idle set screw so the original TBI electronically is calibrated already and will either work fine or not if the computer is not damaged. I know, the Suburban is likely gone by now but in case not. TBI is not junk. They are the most reliable FI ever and are not complicated like the late FI is that requires electrical engineering and expensive equipment to diagnose.

[@mikem5475]

Exactly. You are smart

[@curtisryan6911]

If you have the headlights on auto, check the parking brake. It turns off the lights when engaged, even just a click. Just a thought.

[@mathewdavenport593]

Hydro boost is a upgrade 👍🏼. When new the iac (idle air control) needs adjusting. I forget the procedure. But I’ve been there. Other than that. May have shorted the computer out. Both easy cheap fixes.

[@taylor06051]

Put the old one back on and fix the wires you crushed. Trace them back to were they look good.

[@taylor06051]

Forgot. Also check the back of the old were the plug was at.

[@tony_25or6to4]

It used to be a diesel, hence the hydro-boost. Diesel engines do not crate much, if any, vacuum.

[@Blue04Z71]

Hydroboost is common in the larger trucks. A lot of guys swap to it to help with braking with larger tires. Do not get rid of it. You should also check fuel pressure and check for vac leaks.

[@Blue04Z71]

Also ohm our the temp sensor in the intake. Known for going bad and causing running issues.

[@Tedybear315]

Hydro Boost: Okay system when it works. Had that in one of my old Astro Vans that thankfully was still under warranty when the seal popped. Dumping PS fluid all over the place! The dingbat at the dealership said "They never fail....." And then had to eat crow and replace it under warranty. (failed at 32k.....part was over $650.)

[@Justin-mp7zh]

Orange injectors are for the 350 my friend. I believe 55lb an hour. Your injectors are red if i remember correctly and its 96lb or something an hour. I know this is wayyyyy late but I just got your video as a suggestion so here i am! good content my friend!

[@4739-g9c]

Yes big blocks weigh around 700-725, sbc ~620s iron vortec(LS) ~590s accessories headers wiring, starter, etc, all components that it would take to make it a runner.

[@dominicene3647]

i think its fuel or air related. My first guess would be the injectors then either the fuel filter or fuel pump screen or even fuel pump. Lastly check the vacuum lines and vacuum advance unit mounted on the distributor. I would test the fuel pressure if its getting between 9-13 psi. It wouldn't hurt to inspect/check the TPS, CTS, IAC, EGR and clean if necessary.Lastly I would check and examine if the fuel pressure regulator is leaking. Good luck Randy, hope the fix is not timely or costly.

[@demondparish5558]

Keep your head up you will figure it out have faith

[@rickygambill723southsideki7]

Check the vin on the motor and it should tell you what year the motor is

[@Shade_tree_garage01]

My 1982 C30 had a hydro Boost setup, had nice brakes

[@bstephens4801]

Randy, Hydroboost is typically used on GM and Ford Diesels. The engines have no throttle so the manifold vacuum is unreliable. I have seen hydroboost on the gas burners but that is not as common. Another option for diesels is an external vacuum pump and conventional vacuum boost. If your hydroboost pedal pulsates, flush the fluid in the system. Also, you said you pinched the injector wiring? If so, you may have shorted the driver in the computer. You should be able to open the throttle and see fuel spraying from each injector. If not, you may have killed the driver electronics that fire the injector on one side. Or you can unplug one injector at a time and see if the engine operation changes.

[@Shawnsullivan7]

Hydraulic boosted brakes is common with diesels because diesels do not build vacuum like gas engines. I would check the resistance on the wires going to the injectors by probing them before they were pinched and at the connectors. Last, rule out bad fuel. Run the truck of a separate fuel source and see if the problem disappears.