I think I effed up my IAC. plus other stuff..
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Junior Member
Joined: Sep 2003
Posts: 26
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From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
I think I effed up my IAC. plus other stuff..
Hi! I have an 87 Chevy truck with a LO5 motor. I was going to re-gasket the TBI unit with a kit from Autozone (the $32 one). I took the unit off with no problem and proceeded to blast it with carb cleaner. I left the IAC on because it was very difficult to get it a few turns loose, so I just tightened it back down and carried on. 
Anyway, I carried on with the tear down and rebuild without a hitch. Everything went smoothly until I was ready to fire up the truck. I cranked her over and hear an awful hissing sound. I get out and check the engine and find gas on both sides of the engine. 
So I get my wife to come out and turn the engine over so I can see what's up. I have fuel spraying out sideways from under the fuel pod cover, between the injectors and fuel regulator. 
So, here I sit looking at the only TBI site I know of and what do I read in the FAQ post? Your supposed to "jump A and B to reset the pintle"? and don't use harsh cleaner? Would an effed up IAC cause a fuel leak like this?
btw, I took care to make sure every bolt was tightened real good, every gasket was replaced (all o-rings, metal o-rings, etc.), and that the injectors were seated right.
Anyway, I carried on with the tear down and rebuild without a hitch. Everything went smoothly until I was ready to fire up the truck. I cranked her over and hear an awful hissing sound. I get out and check the engine and find gas on both sides of the engine. So I get my wife to come out and turn the engine over so I can see what's up. I have fuel spraying out sideways from under the fuel pod cover, between the injectors and fuel regulator. So, here I sit looking at the only TBI site I know of and what do I read in the FAQ post? Your supposed to "jump A and B to reset the pintle"? and don't use harsh cleaner? Would an effed up IAC cause a fuel leak like this?
btw, I took care to make sure every bolt was tightened real good, every gasket was replaced (all o-rings, metal o-rings, etc.), and that the injectors were seated right.
Thread Starter
Junior Member
Joined: Sep 2003
Posts: 26
Likes: 0
From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
OK, I've been looking at some things and even if I messed up the IAC, the fuel should still spray normally.
I forgot to mention "why" I was rebuilding the TBI. Here goes.
The truck cut out on my way home from work. I got it started again but it was running really rough to the point where I had to give it gas at stop lights to keep it from dying. I got home and took the air cleaner off so I could watch the fuel while it idled. I had no spray on one side and post-nasal drip on the other. No wonder it was trying to die. So, I figured I'd do a rebuild before spending $$$ on new injectors and see if by some grace of *** it would work.
Well, it didn't and thus we have my first post. And I'm a idiot.
I forgot to mention "why" I was rebuilding the TBI. Here goes.
The truck cut out on my way home from work. I got it started again but it was running really rough to the point where I had to give it gas at stop lights to keep it from dying. I got home and took the air cleaner off so I could watch the fuel while it idled. I had no spray on one side and post-nasal drip on the other. No wonder it was trying to die. So, I figured I'd do a rebuild before spending $$$ on new injectors and see if by some grace of *** it would work.
Well, it didn't and thus we have my first post. And I'm a idiot. 
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From: PA
Car: 94 9c1 Caprice
Engine: LT1 (3-fity)
Transmission: 4L60E reBUILT
Axle/Gears: 3:08 POSI (out)
Sounds like your injectors are FUBAR (just kidding), but they do sound like they are pluged which could block off fuel (your dribbling). It still should not shoot fuel out the sides unless a gasket is out of place.
It could be a grimlin too
It could be a grimlin too
Thread Starter
Junior Member
Joined: Sep 2003
Posts: 26
Likes: 0
From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
I took it back apart to make sure the injectors were seated correctly. The gasket between the top and bottom parts of the pod looks fine. No tears or rips. Looks just as new as when I put it in this morning.
Exactly what I was thinking. I had to have done something wrong putting the gaskets in. Because if the injectors were clogged yesterday and the fuel rail wasn't spewing fuel then, it shouldn't be doing it now. I'll take a fresh look at it tomorrow.
It still should not shoot fuel out the sides unless a gasket is out of place.
Thread Starter
Junior Member
Joined: Sep 2003
Posts: 26
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From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
I finally got around to looking at it again. I found the problem on why it's spraying fuel out. I didn't get the diaphragm in the fuel regulator seated right. Every time I try to get the spring in there it pushes the metal center down and deforms the rubber edge of the diaphragm. I can't get it to seal right. Any tricks to get the spring in there without messing up the seal?
Not my pic, borrowed it from another site..
Not my pic, borrowed it from another site..
Last edited by C&C Chevy; Mar 26, 2006 at 02:35 PM.
Thread Starter
Junior Member
Joined: Sep 2003
Posts: 26
Likes: 0
From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
OK, so I got everything running and I think were back to the effing the IAC up. Cause it's idling at like 1400rpms.
I looked at the IAC part of the "New to TBI" thread (see below). The link for the expanded view pic doesn't work anymore. To replace the IAC, all I have to do is follow step 1 and step 5, correct?
I looked at the IAC part of the "New to TBI" thread (see below). The link for the expanded view pic doesn't work anymore. To replace the IAC, all I have to do is follow step 1 and step 5, correct?
In addition to this, I want to clean my IAC. How can I do this?
1). Remove the IAC. It can be found on the pass side of the tbi. See the link below for an expanded view of the IAC...
http://216.121.161.76/files/TBI220.jpg
[Thanks Vader!]
2). After you have done so, reconnect the IAC connector and place a bag or towel around the IAC so the pintle doest go flying off. Once this is done, jumper pins 'A' + 'B' in the ALDL connector. Once jumpered, turn the key to the ON position, but dont start the car. The ecm will eject the IAC pintle. Turn off the ignition and remove the IAC and its compontents.
3). Next step is to clean the parts. I like using lighterfluid or naphtha. Cleans and leaves no unpleasent odor once it evaporates. NEVER use harsh solvents or dip in/spray the IAC with cleaners!!! It may be damaged! Use a toothbrush to remove all the carbon deposits from the guide, spring, and the threads on the pintle shaft. Once dry lightly coat the pintle shaft and guide with a light grease or oil.
4). Reassemble. Place the spring over the pintle and place the pintle shaft in the guide slot in the IAC. It wont jsut go in as there is an armature with gear teeth on it. Screw the IAC pintle in untill the guide slots on the pintle shaft just meet up with the guides in the IAC main body. From there gently rock the IAC pintle back and fourth while applying light pressure untill the pintle gets partially back into the IAC.
5.) Reinstall the IAC. Screw it in by hand and if you feel any sort of resistance, STOP!!! The pintle has bottomed out. Reconnect the IAC and pull the jumper out of the ALDL if you have not yet done so. Lightly depress the gas pedal and start the car. Let it run for about 30 secs and shut down. Do the following to tighten the IAC:
As posted by Vader:
Quote:
You can use a wrench, but remember that the torque specification for an IAC is 13 ft/lb for '85-'89 , 30 in/lb for 1990-on, or not very much torque at all. Hand tight and about 1/16 additional turn is about all that's necessary.
1). Remove the IAC. It can be found on the pass side of the tbi. See the link below for an expanded view of the IAC...
http://216.121.161.76/files/TBI220.jpg
[Thanks Vader!]
2). After you have done so, reconnect the IAC connector and place a bag or towel around the IAC so the pintle doest go flying off. Once this is done, jumper pins 'A' + 'B' in the ALDL connector. Once jumpered, turn the key to the ON position, but dont start the car. The ecm will eject the IAC pintle. Turn off the ignition and remove the IAC and its compontents.
3). Next step is to clean the parts. I like using lighterfluid or naphtha. Cleans and leaves no unpleasent odor once it evaporates. NEVER use harsh solvents or dip in/spray the IAC with cleaners!!! It may be damaged! Use a toothbrush to remove all the carbon deposits from the guide, spring, and the threads on the pintle shaft. Once dry lightly coat the pintle shaft and guide with a light grease or oil.
4). Reassemble. Place the spring over the pintle and place the pintle shaft in the guide slot in the IAC. It wont jsut go in as there is an armature with gear teeth on it. Screw the IAC pintle in untill the guide slots on the pintle shaft just meet up with the guides in the IAC main body. From there gently rock the IAC pintle back and fourth while applying light pressure untill the pintle gets partially back into the IAC.
5.) Reinstall the IAC. Screw it in by hand and if you feel any sort of resistance, STOP!!! The pintle has bottomed out. Reconnect the IAC and pull the jumper out of the ALDL if you have not yet done so. Lightly depress the gas pedal and start the car. Let it run for about 30 secs and shut down. Do the following to tighten the IAC:
As posted by Vader:
Quote:
You can use a wrench, but remember that the torque specification for an IAC is 13 ft/lb for '85-'89 , 30 in/lb for 1990-on, or not very much torque at all. Hand tight and about 1/16 additional turn is about all that's necessary.
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Thread Starter
Junior Member
Joined: Sep 2003
Posts: 26
Likes: 0
From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
OK, anyone here? 
I replaced the IAC. Followed the instructions. Made sure the pintle was less than 1 1/8" from the base so it wouldn't bottom out. Took the truck out and got it up to operating temp. and got it up to 45 mph so the ECM would reset the idle speed.
Well, it didn't. I'm getting a code 45 now. "Rich exhaust indicated"
Has to be the the regulator. Right? What else would cause this?
I replaced the IAC. Followed the instructions. Made sure the pintle was less than 1 1/8" from the base so it wouldn't bottom out. Took the truck out and got it up to operating temp. and got it up to 45 mph so the ECM would reset the idle speed.
Well, it didn't.
I'm getting a code 45 now. "Rich exhaust indicated" Has to be the the regulator. Right? What else would cause this?
Thread Starter
Junior Member
Joined: Sep 2003
Posts: 26
Likes: 0
From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
Ok, I replaced the o2 sensor(old one was pitch black with sute(sp?). Fired up the truck and the bad idle problem is still there. Thought I had it that time. Think I'll try the TPS next. Then maybe the fuel evaporator canister filter. Going to check all the inexpensive stuff before breakin the bank on new injectors.
Think I'll try the TPS next. Then maybe the fuel evaporator canister filter. Going to check all the inexpensive stuff before breakin the bank on new injectors. 
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Joined: Mar 2006
Posts: 163
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From: Houston, Texas
Car: 1991 Camaro RS
Engine: 5.0 TBI
Transmission: T5
Axle/Gears: 3.08
sup dude.. i too have just recently rebuilt my TBI using that same kit form Autozone....and as far as the regulator, there should have been two long screws that came with the kit, those were to aid you in lining up the holes for the diaphram...
but yea, i too have a bad idle problem, so i just uncapped my "minimum air" screw on the drivers side of the TBI and bumped it up to idle at like 1000 until i can fix it...
quick question dude, if you put the paper clip across A and B and turn the key on, does your IAC sit there and click and make noise (with IAC installed)???
but yea, i too have a bad idle problem, so i just uncapped my "minimum air" screw on the drivers side of the TBI and bumped it up to idle at like 1000 until i can fix it...
quick question dude, if you put the paper clip across A and B and turn the key on, does your IAC sit there and click and make noise (with IAC installed)???
Thread Starter
Junior Member
Joined: Sep 2003
Posts: 26
Likes: 0
From: Oklahoma
Car: 1987 Chevy truck
Engine: LO5
Transmission: 700R4
Axle/Gears: 3.07
My kit didn't come with any aligning screws.
No, I didn't jump A and B. Are you asking me? Cuase I got no idea if the IAC it should or shouldn't be doing that! I try it out tomorrow.
I pretty sure I'm dealing with a rich fuel problem. It'll bearly keep idle and feels like it's bogged down. Didn't have time today to look at it. I've watched it idle and it looks like there is way too much fuel coming out. Shouldn't there be two pulsing, alternating cones of fine fuel mist? Mine has the cone shape but they look more like a couple of shower heads being turned on and off.
No, I didn't jump A and B. Are you asking me? Cuase I got no idea if the IAC it should or shouldn't be doing that! I try it out tomorrow.
I pretty sure I'm dealing with a rich fuel problem. It'll bearly keep idle and feels like it's bogged down. Didn't have time today to look at it. I've watched it idle and it looks like there is way too much fuel coming out. Shouldn't there be two pulsing, alternating cones of fine fuel mist? Mine has the cone shape but they look more like a couple of shower heads being turned on and off.
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