Rebuilding and modifying a GM TBI Fuel Injection Unit

[@mnwlindsay]

I really liked how you showed most of what you did, not many things happened off camera. I also liked that you talked about what each part on the TBI was, for those who aren't so knowledgable. TY.

[@ThumperDana]

My son and I rebuilt the throttle body for his 87 chevy R10. It was night and day difference. I STRONGLY recommend buying a ultrasonic cleaner from HF. Also, the rebuild kits come with 2 long screws for helping put it all back together without pinching the diaphragm. LASTLY, get some Simple Green HD PURPLE! Regular Simple green will degrade aluminum. Great video dude!

[@TravisReddell]

Thanks, I was wondering what those long screws were for.

[@jonny_gass]

So glad u made this video man lol. 9 years later and this is helpful as he!!.

[@MrZayne8]

I've watched this video numerous times over several years now and it's good to come back to it. Still the best rebuild video on youtube. 🤘

[@FuelInjectionSucks]

Don't expect the world, but I will say this. Every year I take this truck across PA for a car show, usually it uses half a tank each way. This year it went the whole trip and only used between 1/4 and 1/3 of a tank TOTAL. So something changed.

[@Gabriel.4190]

Are you implying its cause of the TBI rebuild.

[@eastcoastken]

​@Gabriel.4190 no because he trailered it there and back. The little bit of fuel used was because he drove around the show

[@rickw2776]

I'm a big fan of the TBI having grown up with carbs. Any type of fuel injection is a lot simpler than any carburetor. Fortunately for the motor heads born after 1985, almost all cars and trucks are fuel injected now. This is an excellent video. He speaks clearly and sticks to the subject at hand. The only thing I would add would be to apply some sort of lube on the O-rings before installation particularly on the ones on the injectors. I've found that those seals could roll out of their grooves when pressing the injectors in.

[@carlosvalentin856]

Yes you should add some trany oil on the rings. Good thought, he also did not show how to put in regulator spring. I thought the video was helpful. On till i try to put in that spring. I buy a rebuild kit it has two screws long about two inches. That is the only way that you can put in that spring. is with those screws. It took me two hours to figure it out. When you make a video, you have to show the hardest parts also. I ran into some trouble with that spring.

[@galehess6676]

@@carlosvalentin856 how is this done?

[@carlosvalentin856]

@@galehess6676 watch the other videos on this than u will learn.

[@AZStarYT]

​@@galehess6676 You could just buy a couple long screws at Ace (match the threads to the short ones used on the regulator). Put the spring in the cap and see about how far off the base the flange is, then pick screws about that long or a little bit shorter. Install them on opposite corners and tighten evenly. You're just wanting to use them to guide the body while you push down so it doesn't push the diaphragm in to one side or the other and damage it. Once you have two of the short screws in (not tight yet), remove the long ones and put the other two short screws in. THEN tighten them, doing opposite sides (cross pattern). I grew up in a machine shop, so always like to snug screws first on anything, then torque to spec if given. Just remember you're working with soft cast aluminum and steel screws, so if you have no torque specs, go just a little past snug, don't overtighten.

[@galehess6676]

@@AZStarYT Thanks for the details!

[@EricJKing]

My 91 K1500 has been sitting for about 2 years now without running. Thanks for giving me a better view into what’s going on inside that unit.

[@charlesparr1611]

Hey, just wanted to thank you for a great tutorial. My long awaited startup should happen within the week and the throttle body is about the only thing I am not nervous about.

[@frankdavidson9675]

2009 ram 1500 fuel injection perfect bought new never fail to start im 88 this is the best truck of my life and iv owned quite a few

[@chrissmith9858]

I installed the CFM Technologies adjustable pressure regulator in my 1992 454 TBI 2 weeks ago. A couple of comments about the video. First, bending that vacuum tube below the new pressure adjuster thumb wheel does nothing. The thumb wheel is so close to the base of the metal tube that bending it does not provide any additional clearance that I could see. What I discovered was that I needed to screw in that thumb wheel A LOT more that I originally thought. There was tons of clearance when I got the pressure set to 13 psi. Lesson? Don't bend the tube at all (this is assuming you are still using the old stock spring in the regulator). In the rebuild kit there were two very, very, very, very, very small round filter screens. I am talking about 1/8" in each direction. After calling CFM Tech (GREAT tech support by the way), they said these go in the side of the injectors below the sealing o-rings. Never would have seen that or figured that out without that info. Definitely buy the fuel pressure gauge and adapter. You can't adjust what you cant measure. The net result? My 1992 31 foot Fleetwood Bounder went from 5.2 mpg to 6.67 mpg. NICE! Still working on a couple other issue with wide open throttle performance but there is no question adding this adjustable regulator absolutely helps. WAY more power and 20% better fuel economy.....Nice :-)

[@randy1ization]

how does the higher fuel pressure make more power

[@KJTUSKJTUS]

@@randy1ization because the combustion within a cylinders goes off of an air fuel ratio(afr). The ideal afr is 14.7:1. Assuming that at 13psi of fuel is at 14.7:1 or less (i.e 13.5-14:1) you will be running slightly rich providing the best combustion, fuel economy, and power. Without the proper fuel pressure you are running rich, too much gas (less than 14.7:1) which is fine but you are losing power and fuel economy. Or you're running lean, too little fuel (more than 14.7:1) which is bad because the heat within the combustion chamber can melt Pistons, rings, etc. And you will also be losing power

[@CrimsonSkyz500]

@@KJTUSKJTUS does increasing PSI not mess with the onboard computer?

[@waynewilliams5802]

@chrissmith...hey mane how hard was it to do bone

[@chrissmith9858]

@@waynewilliams5802 Sorry for the delayed response....life events, covid, etc......:-). If you've ever rebuilt a standard carb with float chambers, jets, etc. This is about the easiest job you'll ever do. While they were out, I did take the time to send the injectors off for testing/cleaning (lots of companies around that do this). Since I posted this, I also noticed that I was still losing power when climbing hills as I pressed the accelerator hard. It seems like I had more power when my foot was lightly on the accelerator pedal versus firmly pressing down. I finally decided to check the base timing which I've never worried about in the past, because once set, it shouldn't move. The engine computer relies on the base timing to be exactly 4° BTDC (on this engine) in order to do it's job correctly. What I discovered was it was set to 4° ...... ATDC! The prior owner saw a 4° mark and set it to that, but it was the ATDC mark. The engine was basically running 8° retarded. After fixing THAT minor little issue, the motorhome was leaping up long hills when accelerating hard (as much as a big motorhome can leap) and the fuel economy went up to around 9.2 MPG. Nice.....

[@MG-th9sl]

Great video with excellent explanations on how this works. Thanks

[@DirtMvGirt]

He's not even here anymore... But damn this dude is legit. He had a talent.

[@shawnrobinson8428]

I like how you explain what the parts are supposed to do

[@thomasmchugh845]

This is a great video. No useless blah blah talk. Very informative. I am a little confused on how to and why the regulator needs adjustment and the need to drill out and insert the new style adjusting toolOther than that an excellent video. Thanks

[@FuelInjectionSucks]

+Thomas McHugh It's just an aftermarket regulator to raise fuel pressure, it is not required at all, just something optional I did. Some of the OE regulator housings are also adjustable. They have a set screw that is loctited in to a set pressure, but there is no way to get to the screw without first taking the throttle body apart.

[@thomasmchugh845]

+Fuel Injection Sucks Thank you for your reply to my inquiry which explained everything . I think I needed to also to view your part two video which I did to understand the adjustable regulator setup. Appreciate you taking the time to reply to my comment.

[@1169tech]

Older cars and trucks get worn out. Being able to adjust pressure, allows for better performance..

[@icefishingmn5879]

I added new injectors and now it leakes fuel and doesn't turn over or start any help would be helpful. Thanks

[@79bonscott]

My '90 Silverado 350 TBI needs this done. Thank you much for this awesome combination of quick but VERY detailed video, best of the maybe 5 or 6 others I've watched. Thank you.

[@shadowopsairman1583]

See if there is a difference with the 454 and the 262

[@gaminredneck5216]

just came across this vid, ordered the parts from summit, getting them tomorrow!

[@plumbingstuffinoregon2471]

Thanks for this video! This is going to really help me with my '85 Cadillac. It's engine was replaced in 1994, so the throttle body injection thing is almost identical to this one.

[@austinado16]

Fantastic job making this video! I've got a '90 'burb that I've been wanting to do this too, including the adjustable fuel pressure regulator, and gauge. Will probably even mod the tops of the venturi's and take off that raised band, and put the plastic pod spacer in. The truck does a lot of towing, so anything that helps with power output and maybe fuel mileage, is worth doing.

[@cecilsabourin9462]

So any info on fuel presure differences , would a simple internal spring spacer ( washer) do just as well ? ,PS your sound level is way to low .Did u flush the injectors ?

[@Jerkwad152]

I modified my TBI by taking it and the intake off, putting it on the bottom shelf in my garage, and replacing it with an Edelbrock 1406 carburetor. :)

[@jamest.5001]

I saw a project where they ran two of the throttle bodys, I think only a single idle air motor. And paralleled the injectors! With a bit of ecm programming. I thought about doing it myself. But a 750 double pumper took the place of that idea!!

[@DanielWilsonSR]

Thanks for the video! Got a 88 chevy pickup with a 350 and installed a jet performance fuel pressure regulator similar to the one you installed. My question is after installing it there is no way to test the pressure to the injectors. The gauge you talk about is before the regulator... Does this give you the right pressure readings or just the pressure from the fuel pump?? Thanks!!

[@DarrenCharron]

That is pretty cool I just picked up a 1987 GMC 1 Ton and should probably look at rebuilding the TBI throttle body.

[@jeepcreep13]

Great video. I saw someone asked about the injectors orientation whe putting them back in. Isn't there a notch that needs to be lined up? One injector facing with notch facing forward and one facing backward.

[@charlesguinn4316]

Put a new kit in mine today, but I had to fight those injectors out & in! 93 GMC 350ci 1500 would NOT idle at all~ but this solved my problem... Just need to reset (initial timing) on the new dizzy, and I'm back on the road.

[@Rocketyt]

I'm so gonna do this. I have a 92 454 and developed a nice stutter to the point it won't run. So....I'm going to replace the Coolant Sensore, Map Sensor and I was going to rebuild the Idle Air Control Valve until I watched this video. But....However... I'm now going to rebuild my TBI Fuel Injector Unit after watching your video 3 more times. Great video but just too much beer right now. You da Man!! Thank you...Rocket

[@UtahDarkHorse]

I'm going to pick up a kit this morning to do my '89 gmc c3500's 7.4l tbi. I know it will be a bit different but thanks for the awesome video. Have rebuilt carbs before, but not tbi. Am going to add the regulator you suggested. ☺

[@seanstraw8688]

Haven't needed to useit for the injector screens, but if you hunt around in your toolbox for a CLEAN socket (or box-end) that fits over the end of the injector, you can use that to push the screen on with even pressure all around.

[@whitrich47]

Very nice video. Wish I had watched it before rebuilding mine. After rebuild, when key is turned on, the TB bowl fills up on top of the throttle plate then the gas leaks down into the manifold. Also, the throttle shaft is leaking onto the manifold at each end of the shaft. When I reassembled the TB, I noticed that the Air valve plunger did not have any play in it, in or out. Can I put new seals on the throttle shaft? Could I have replaced the fuel pressure regulator backwards?

[@daejuanj]

Good to know, only thing I know on the truck is a throttle body spacer mod. I'm trying to troubleshoot my truck running lean causing it to stall. So hopefully taking the TBI apart would lead me to the cause

[@L1dechuy09]

Thank you now I’m more confident to rebuild mine.👍

[@catdakman1273]

How do you measure your adjustable fuel pressure now??? The return line??

[@edbrazman357]

This video rocks!!! I did the rebuild with this as my guide & it all came together perfectly!! Thank you so much, saved me some dough on my work van.

[@3rdGenGuy]

I rebuilt a 91 TBI and the truck runs way better. BUT The noise of the injectors is WAY louder now. Did i do something wrong?

[@24BLUEELMO]

Probably because you sonic cleaned the injectors?

[@Texassince1836]

No, base idle is through the throttle plates, there Is an idle adjustment on the drivers side. The IAC bumps the truck over base idle for cold start, abs when the ac compressor is engaged

[@adriannaw6294]

rebuild mine, thanks, to your video. i had some issues with my tbi when i put a v8 350 5.7L in my Astro van. found out that i had a bad ground and one of the injectors were bad. Thanks again for the great video.

[@exbioman]

Good job! Would be great if they still made the AWDs! I miss my Safari. It was a handful of trouble, but great AWD and interior. Wanna go camping?

[@melindaortiz9741]

How does it ride with a heavier front load

[@imac7531]

@@melindaortiz9741 with a stiffer front suspensions? rides like a V6.

[@lnsvett1]

Just wanted to say thanks. You made a very well put together video.It had all info needed without a bunch of useless talk .I watched it one time, then ordered parts and did my own with no problems. Thanks again!!!!

[@FuelInjectionSucks]

Check fuel pressure. If you have the required 12-13 PSI, I'd check out the pickup coil inside the distributor. The computer uses it to pulse the injectors, and they get a problem reading at low RPM. Its rare to see both injectors fail at once. Get a "Noid" light set, it's a loan tool at Autozone, and plug it into your injector harness at the TBI unit. They should flash as the injector gets the signal to fire. If they do nothing, the computer isn't signally them to open.

[@darinr9424]

control module in that small cap hei is notoriuous for failing DO NOT BUY THE AUTOZONE modules... POS lucky if they last a month. no fire on both inj. almost promise its the control module.

[@FuelInjectionSucks]

A test light can overload the ecu, but I have used one before. I'm not sure, but there is a good possibility that the injectors are constant hot, and the ECU grounds the circuit to fire them, so test from the ground to the hot on the battery, or just get a noid night set to be safe.

[@angelpineda]

hi good nights i have a G20 GMC van, with 5,0L v8, and the comsuption gas is high! i rebuilt the TBI with gaskets and is the same. the fuel pressure regulator can be fail? or the return gasoline can be covered? the ECT sensor is working fine, no "service soon engine" lights, and the O2 sensor is woring fine, the maf and the other sensors too. how can be the problem, thank´s

[@w9x7cv3vg6]

Hello,i was just lookin at your video getting tips on the trottle body cleaning etc etc,now i have a 89 trottle body that was on a 305 that i put on a 350 10 yrs ago,history is that since i put a new 350 in it,i only drove it 10,000 miles...sooo i was just wondering if that idling air control valve,if faulty,could it make it use more gas when idling than when even moving around,that seems to be the case,plus i wanna get that kit anyway so i am looking into it,i did not hear anything in the video or anywhere on that idling air valve,if it is,any comments thanks and get back

[@clayton_the_redneck8195]

So do you put the backup rings on the pods or not ? I have 2 ,93 4.3L TBIs but they only had the o ring , I rebuilt one already and didn’t use the backup ring and a month later it has started to leak above the pod. Is that because I didn’t use the back up ring ? Every video I watch everyone seems to completely skip over that

[@Smaze1762]

where did you get the adjustable fuel pressure regulator screw from? any benefits?

[@FuelInjectionSucks]

Yes, the injectors can go bad. The kit is about $35. You can get it at almost any auto parts store. You have to do more research to see if this is why it's not running. First make sure you have fuel pressure, and verify the pump is even running. If you do have fuel pressure, borrow a set of "noid lights" from Autozone and plug them into the injector wiring. You should see them flash. This will verify if the computer is signalling injector pulse or not.

[@maronielbethishou5912]

Where can i buy the fuel pressure regular and that fuel line fitting with the port to get fuel pressure?

[@TheRoguelement]

Next one you do try using some marvel oil the rubber parts go back so much better and do NOT stick causing rips..

[@HeyHeyItsKyle]

I wish there were more videos like yours. No nonsense, just "here's this part, here's that part, here's where the bolts come out, here's where the lines come in, this is what this part does, etc." Too many videos start out rambling about irrelevant stuff with shaky, unfocused videos, pointing through the engine compartment with greasy fingers. lmao, good on ya bud. Thanks for the video!

[@00olds]

i had an 89 camaro 305tbi that did that after it warmed up to operating temp, it turned out to be a driver in the ecm that was shutting off the fuel pump when warmed up

[@mrsuarez430]

Hey bud question I have a mercruiser 5.0(305) engine same tbi throttle body and injectors etc difference is the bowl regulator has a tube as an over flow but that's essentially to tell you the Diaphragm is bad right there's not sppposed to be fuel getting under the Diaphragm where the set screw and spring sits right? I have a flooding issue with it that floods the engine severely through that tube

[@gregdevries1752]

Have you ever removed the armature the linkage connects to at the end of the shaft? I need to remove one from a stock unit to put onto a Holley TBI unit that has a different armature?

[@jjon901]

Thanks, just wanted to make sure there was no "front or back" orientation when putting the injector back.

[@thedobermangang3503]

hey i have a question for u i have the same set up but when i try aDJUST IT MY GUAGE IS STILL REAding 10 psi it wont go no higher i trying to get it to to 14 psi

[@etmesi]

I wonder how this would work? Say you get a vintage 1992 454 throttle body and a Chevrolet Performance LSX 454 Long Block Crate Engines 19417357. Would the Throttle Body work on a newer motor like that?

[@Deckers2006]

Wouldn't this mod only serve to enrich the fuel mixture? I need to lean mine out instead. Is there a simple means of spring swap to lean thrm?

[@ThesiKCOne661]

i have a problem i dont get fuel out the tbi injectors i do have spark because if i spray starting fluid it starts for 3 4 seconds. i recently changed icm, ignition coil, pick up coil. and now it dont start before i did all this it started but wil die on me after 20 minutes and will be able to turn the car back on in 30 minutes.after it has cooled down , so thats why i changed all these things but now it wont start.

[@RebellionWithoutCauseBand]

+The siKC One T.V Check the ignition control module again because they have a habit if not handled literally perfectly can die after one use. Seen it done twice. Its usually a ground problem but that will cause no spark or start. Also if the injectors aren't firing check the fuse under the dash labeled INJ A + B to see if its still good. It tells the injectors to fire so if its not working correctly you won't get fuel.

[@benjaminbreakiron87]

@@RebellionWithoutCauseBand i have a k5 blazer runs if i put gas durectly in change this crap 2ice and fueses are good plz help

[@toddbarnett6834]

I have a 1994 Chevy Suburban 2500 454/7.4. Is the throttle body the same as the one you replaced/ Where did you get the throttle body kit?

[@davidfink9729]

What should the fuel presure be on a 350 gmc tbi?

[@FuelInjectionSucks]

9-12 is spec. Pump puts out 15psi max.

[@davidfink9729]

I bought the presure gauge , adapter for presure side , and adjustment knob ( red ) from CFM TECHNOLOGIES. Put it on and no leaks. After little adjustments I had it at 11.5 lbs . Went for a test drive and truck just quit. Had to be towed home by dads truck . Took off fuel filter ( motor side ) and bumped motor over and getting plenty of fuel . But no fuel is getting to TBI. What could be my problem??

[@FuelInjectionSucks]

@@davidfink9729 What pressure it is showing now that it's not starting?

[@davidfink9729]

None. No presure. No fuel is getting to tbi

[@FuelInjectionSucks]

@@davidfink9729 If you crack the fuel at the TBI unit does fuel come out? How about just cracking the return line?

[@johnbaker6450]

Not sure if it has already been asked/addressed, but can u tell us what brand or where you found kit with psi adjustment knob, gauge, and fitting? Please and thank you. Awesome video. Gonna tackle mine soon.

[@johnbaker6450]

Sorry, i just rewatched and caught cfm technologies

[@DMX-PAT]

Is there a performance chip you can get for these units, can they be tuned for fuel economy over horsepower because for some reason I would love to see what level efficiency they are capable of.

[@kevinferrell7033]

I have a 1991 Silverado with 350/5.7 tbi fuel injector. One injector on the left side. Left side standing in front of the truck is spaying a what i think is more that a mist and also i can see like bubbles dropping as its spraying and black smoke comes out the drivers side/right side tailpipe / truck has sidepipes under the doors. I was told the left injector works the right side exhaust and the right works the left side exhaust. Is that right? Mine is left injector poss. over spraying with black some out the right sidepipe/muffler. Muffler tip is black on right /driver side only. I put new plugs,wires,cap,rotor,breather,bank 1 02 sensor. Had 1 right side back plug was coroated bad. I also tried a new coolant temp sensor. No change. Is there anything i can do to fix this injector? Also will it hurt or help to soak a old injector in transmission fluid?

[@leoleonel6234]

subbed thanks for clear understandable info with no mindless ramble or death rattle music. am doing mine soon while watching yours ..Its that Good !

[@yausaptheshasuabary180]

Awesome video. Quick question. Is there any way to mess up the orange regulator piece when installing? Mines is leaking from somewhere in the rear. Not sure if I somehow installed it slanted

[@robv5343]

Hello, I have a 95 4.3 V6 Silverado and is making a loud whistling noise, I was told it was the alternator so I changed it together with idler pulley and the serpentine belt and nothing noise was still there... it turns out the noise is coming from the tbi, do you have an idea of where from the tbi the noise might be coming from? If I were to rebuild it u think the noise will stop?? Any help helps. Thanks.. great vid by the way!!

[@FuelInjectionSucks]

Probably a bad base gasket. Its whistling from a vacuum leak.

[@luckybeto1540]

I did every step you mentioned now the truck ticks when I'm driving. Some say the new regulator is bad, some say the injectors are bad and others say bad lifters. No issues before. What do you guys think?

[@Sleeperdude]

Great information thanks for sharing

[@jimmymoison1631]

I have a 1989 with a 454. Do you have any ideas on getting more fuel? I’m getting ready to install a top-end kit and I’m sure I’m going to need more fuel lol. Great tutorial by the way

[@rmmm6725]

Carb

[@johncooper7988]

I purchased a used Throttle body with the IACV and TPS sensor and rebuilt the entire thing. Everything was cleaned & replaced all gaskets & filters. Took the old one, which is an identical match off the motor this morning and swapped it out with the new rebuilt one. My question is, should I take the idle air control valve and tps sensor off the one that its been running currently, and put them on the rebuilt one in place of the ones that came on the one I rebuilt. I cleaned up both valve and sensor during the rebuild, but wasn't sure if I should have just swapped both valve and sensor from the one I took off, to the one I rebuilt???

[@exbioman]

TPS SENSOR IS MECHANICAL. No difference new or old in my thoughts. $50 waste.

[@alexlopezz6239]

Does the fuel pressure regulator screw make a difference if screwed up/tightened or screw down/ loosened ? And if yes what are symptoms?... Please any comments or tips / advice will be greatly appreciated? First time doing a rebuild on a 454 tbi

[@sega2229]

Been doing this but everytime my injector leaks from up top and im so sure it pinched the upper o ring and I’m right I’ll try to put it on the way you did over the top hopefully it doesn’t tear and leak again

[@WithoutAtaste]

Can you possibly make a parts list; or set of part links? including the company name, and or part numbers links in the description? I need to rebuild my carb soon, I have a high idle problem, and I'm pretty sure it's the gasket under the throttle body; but I'd also like to rebuild it with upgraded parts. BTW your video was awesome! thanks for the help!

[@bogotstogoskiing]

Excellent video! I will be rebuilding my TBI in the next couple of days and now I know what to expect. Awesome :)

[@purestress2]

5 questions: 1. Is there a certain way to disconnect the fuel lines. Like do they spill out or is there a way to close them up or something when you disconnect them. 2. What did you clean the throttle body with? I have carb cleaner I was going to use, can I clean it all with the carb cleaner, every hole, ports etc.. And then after do I let it air dry or do I wipe it with a rag or do I wipe with a wet rag with water to clean off the carb since it's flammable. 2. I was going to clean my iac valve with throttle body and air intake cleaner but you mentioned people tend to mess them up.. How so? 4. I heard that you're not suppose to touch the throttle plates cause you could mess up the adjustments, so how do I clean those with out messing it up. And 5. How do adjust the fuel pressure regulator. Is there a certain way or is there instructions given for how far in you screw it. Sorry for all the questions. I want to make sure I don't mess something up. Please help if you don't mind. I don't trust these mechanics around here no more so I do the work myself. Plus it seems I'm doing better work than they do so far.

[@Arkavian1191]

To disconnect the supply and return lines do the following: 1. Make sure the engine is cool before loosening the fuel lines. 2. Disconnect the negative lead on the battery. 3. Remove the gas cap from the tank, this will bleed out some of the pressure from the system. 4. Stuff some shop rags under both the return and supply fuel lines where they connect to the TBI to catch any gas that may spill out. 5. Loosen the fuel supply line first, some gas will come out so don't freak out. It will be caught by the rags or towels you placed under the lines by the TBI. 6. Then loosen the return line on the passenger side of the TBI. 7. Once both fittings are loose, spin them back with your finger until they clear the TBI nuts, then gently pull the lines back towards the firewall to remove them from the TBI. *Important Note* You will need two wrenches to loosen the fuel lines. You will need one 3/4 end wrench to put on the nut on the TBI and I think a 16 or 17 MM end wrench to use to loosen the actual fuel line fitting. The 3/4 wrench is to ensure the nut on the TBI does not spin while you loosen the fitting for the fuel line.

[@robmcdonald9681]

So let's talk about the small rod with the orange thumb wheel that you screwed into the regulator. What's the next step? Does it get removed? And if so, will it clear the tube that you bent.

[@HWCapps]

Is the TBI from 1990s a good system ? or is it out of date and the Holly Sniper system be better and give better gas mileage ???

[@camkenyon2055]

my 1990 firebird has a hard time starting and runs rich like nobodies business. I'm pretty sure its the fuel pressure regualtor, but do I really have to take the whole throttle body off the intake? anyway around this? looks like a pain having to take fuel hoses off. Thanks, really good video

[@FuelInjectionSucks]

+Cam Kenyon No take the torx screws out and you can take off the top plate.

[@camkenyon2055]

Alright! thanks a lot for replying

[@ryanw.5535]

Great video! Would you suggest going to a 650cfm TBI to improve performance? Motor in question is a 94 GMC 5.7 355ci. Thanks.

[@FuelInjectionSucks]

I still don't believe larger throttle bodies do anything on these motors unless you do other supporting modifications. You need better heads, larger cam, and a better intake for it to even possibly make more power. Most people insist that their "butt dyno" shows a power increase when they swap to a larger TB

[@Garth2011]

@@FuelInjectionSucks I agree on the CFM larger vs. the one for the small block. GM doesn't crank out complete junk and the smaller CFM is there for a reason, low end and smooth. For those who want to alter the emissions, best to simply replace the cam with a roller GM cam.

[@FuelInjectionSucks]

Only way to tell is doing a fuel pressure test. Also check your timing, MAP sensor, and it's possible that your EGR could be hanging open.

[@mattleonard5268]

My problem is the big upper injector orings never seat right when you tighten down the upper part of the injector pod. They just like to sit on top and get crushed instead of pressing down into their respective grooves. And yes I do use grease.

[@CubNole]

The injector pod spacer you were referring to is also sold on Jegs for much less money than CFM tech. It's plastic, not billet....I have had one for a couple of years and it could probably even be made of wood lol billet is unnecessary. Also I took a carbide bit to that "lip" they have going around the top of each barrel....no regrets!

[@90W7]

Great video. What are some good vendors for injector replacement? Other than oem is there a company that sells quality tbi injectors?

[@johnbell6114]

Can most of this rebuild be done with tbi on engine? I just want to inspect injectors, replace fuel screens, pressure diaphragm and any rubber parts that may be dry rotted, Astro van with 4.3 sat in field, replaced fuel pump, has low miles on rebuilt motor.

[@daejuanj]

Exactly what I was looking for, I have a 88' GMC that's running lean with 10PSI. So hopefully this will work. What do you suggest my PSI should actually be at?

[@sheltonstrother140]

My truck want start without pouring gas in the throttle body. I bought a fuel pressure regulator as well do u think it's my problem.

[@FuelInjectionSucks]

No. Most likely your injectors are not firing or your fuel pump isn't priming.

[@PeggyOBrien54]

would like to know where you got the adjustable fuel pressure regulator. cannot seem to find it anywhere?

[@FuelInjectionSucks]

Mine was from CFM technologies. JET also sells them, and I think Jeg's has their own house brand.

[@PeggyOBrien54]

Fuel Injection Sucks Thanks!

[@king21w48]

would the idle are valve make it so the throttle pedal sticks? i have a 1898 chevy v3500 454 with the tbi, some days are worse then others, but while im driving sometimes the throttle pedal will go about half an inch down, then require alot of effort on my part to break it free (im only pushing about 4-5 lbs more then normal) i have used wd40 and lithium grease on the springs on the outside to no avail.... i will be getting the rebuild kit next month btw

[@Ackeljl]

+Garrett Owens throttle cable adjustment?

[@king21w48]

+DaJackal I don't have a cable adjustment piece on my tbi

[@stanriley2020]

Look at the plastic covering over the throttle cables by the throttle body. That is where your issue is.

[@gechpi]

I've been trying to fix a 90 4.3 and it has spark and a rebuilt tbi and has lots of fuel. it isn't starting unless the pedals to the floor. any ideas why it's not starting properly and the idle is rough.

[@SymaticsPsytribe]

Can you adjust the idle screw? I noticed when I turn mine the tip of the screw that touches the throttle doesn't actually move.. Not sure if its made that way so you don't screw up the idle or if the screw is actually broken.

[@jobobsbobjobs8860]

in response to sticky throttle, throttle shaft holes in body casting on mine wore out. open throttle, grab shaft & wiggle back & forth at every 90°. any play & the body is wore out. my machinist line boared it over size & made bushings for it from harley valve guides. works better than new now.

[@waldosx5]

I have a 87 pickup, I just rebuilt the throttle body and got the kit and followed you step by step. I got everything hooked back up and it will turn over but will not stay cranked, any thoughts?

[@purestress2]

Did you ever figure out the problem

[@davids.6476]

Instead of getting the fuel pressure adjuster for $75.00, can you simply stretch the spring a little?

[@jenniesboy]

Very very very helpful Video. I got a 89 K1500. restoring it. i was wondering if you had gained anything from rebuilding it? previous owner "original" tolled me that the truck was maintained but nothing doen to the drivetrain aside from plugs/wires crud like that. it has 211k miles on her and i am restoring the truck. just wondering what i could expect out of it change wise. i have heard people upping there mpg by 4-6mpg but i dont know if its true.

[@FranciscoRodriguez-oq8hq]

I have a 1988 R20 Crew cab and recently while driving it I heard to loud pops, I stop and check everything I could since I didn't have any tools with me. I end up driving her home with out problem. But I have the same problem as some that it bogs down at low speeds or if I'm accelerate to fast. I have the rebuild kit from Autozone but I wonder if I should go ahead an give her a new fuel filter as you mentioned in one of the post. Thanks

[@happyhippie79]

It's always a good idea to change the filter when you rebuild the tbi

[@timmyhenley5775]

At 6:14 next to the spring is a crown looking washer where does that go.

[@asherroyal2758]

You said that they build a spacer to put the injectors up a little bit. What would be the advantage to that?

[@FuelInjectionSucks]

The one problem with TBI injection is the injectors block the airflow into the engine. Spacing them off a bit allows more air flow past them.

[@asherroyal2758]

@@FuelInjectionSucks that makes sense. Thank you for the reply.

[@1953madmax]

thank you for the info my 350 runs with a pre boast of either looking for the fix

[@catdakman1273]

ignition module in distributor fixed my "no prime" problem.

[@zundfolge1432]

step 1. lubricate and put small o ring in the bowl. Step 2 install back up washer for large o ring. Step 3 lubricate and install large o ring on top of back up washer. step 4 lubricate both o ring contact surfaces of injector. Step 5, slowly push injectors into the housing. step 6 evenly torque torx screws after installing injector housing cap or lid. step 7 is check for leaks. Step 8, start vehicle.

[@altlandf]

what part number is that you screwed In to the TBI at 11:23? will it work on a model 700 TBI? Need to know what fuel pressure is. Even though I have a new gm fuel pump in new tank s10 pickup runs like shit. As your name says fuel injection sucks!

[@lackoficko2242]

Haw can wee regulate,fuel injection for different tipe of fuel,in the carb UR Ether ? Plazma tech..❤

[@wimzrxsf]

Very good video the diaphragm and the spring is tuff though.

[@TheXV1CT0Rx]

What kit was that and where can I get one?

[@juppoful]

Anybody know torque specs for the torx screws? I have looked online and my haynes manual with no results.... Someone told me 12 ft lbs, but that seems pretty tight for those little crews lol