I have an '89 Formula that sat up for about 10 days. When I started it day before yesterday, it will start and runs fine, but dies when it should idle. I took it out on the interstate yesterday for about an hour to see if the computer would reset, an it didn't, but I got the service engine light. I took it in this morning, and they said the EGR is stuck open. What do you guys think? Is there any way to fix that other than pulling the head?

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H.D. Tripp-89FormulaWS6

 

who told you that you have to pull the head to change the EGR valve?? If it was the mechanic you took it to you need to find another mechanic. He is definetly trying to rip you off. Get a manual and look at the instructions. It could also be that EGR solenoid located right next to the EGR valve (see pics below, it is the small black box with a hose running from it to the EGR valve and has a pink and white wires coming out of it). Your EGR valve is located on the passenger side of the intake manifold if it's a TBI engine and you only have to remove the air cleaner so you can get to the 2 nuts holding the EGR valve onto the manifold. If it's a TPI then it's located under the Plenum. Either way the heads don't ever have to be removed.

Have you tried pushing up on the diaphragm of the valve itself to see if it is stuck open? It may just need a god cleaning is all. They tend to get a lot of carbon build up inside them and inside the manifold ports. Take it off and use a pipe brush to clean inside the manifold ports and a non-corrosive cleaner like electric parts cleaner or something to spray inside the EGR valve.

Here is a pic of the valve on my TBI engine, a picture of the port when the EGR is off, and a pic of the manifold off with the EGR still on it. I'm in the middle of a intake manifold change so that's why I have the manifold off...ignore how dirty the old one is. Notice how the carbon is built up in the port. The whole job for a TBI engine should be less than 30 minutes. If you decide to buy a new EGR make sure its a GM EGR and not a non-name brand EGR. It makes a difference.

be patient when trying to view the pictures..
http://www.geocities.com/badbird88/t...grsolenoid.jpg http://www.geocities.com/badbird88/t...ckmandside.jpg http://www.geocities.com/badbird88/t...egroldport.jpg

what engine do you have? Put that in your sig. so it will help others and myself give a better explanation of the fix for your problem.

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1988 TA 300+hp 350 w/ TBI and Holley TB unit,
WC T-5, 3.42 gears w/ Auburn posi. MSD 6A, edelbrock TES headers, dynomax 3" cat and cat-back system, ACCEL coil, polyurethane bushings all around, aluminum driveshaft, Mr. Gasket open air cleaner.

1993 S-10 w/ 4.3L V6 TBI, slightly bigger cam, Mild polish job and 3 angle valve job on heads, Edlebrock TES headers, Dynomax cat back, MSD 6A, ADS chip
(bought from my dad)

2000 GMC Sierra Regular Cab Stepside
285hp 5.3L w/ 3.42 gears and locking diff. (sold to my dad..no!!)

 

HDT,

Incidentally, if you have an EGr that is stuck open, your engine would likely idle very poorly if at all. I consider the EGR as a "programmed vacuum leak", and a large one at that. If it were truly stuck open, your idle would suffer dramatically.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Thank you both! I may have left the wrong impression about the head. I grew up calling the intake manifold a head (intake head) and I still screw it up sometimes. Vader, you are right, the engine runs fine, it just won't idle. I can hold the revs with the accelerator, and it will continue to run. Badbird, the mechanic didn't want to work on it, because of the plenum. He just read the code and said take it to the dealer. How do I hold the EGR open? I can see it under the plenum, but I have never messed with it. If I have to replace it, do I just take the center part of the plenum off?

 

I'm not as familar with TPI motors and I have only pulled a TPI off a 85 Z-28. If I remember right you can take the screws out of the top of the runners and the plenum should come off and then you can access the EGR. There may be a few other accessories that have to be unscrewed from the plenum to get it off but like I said I'm not that familar with the TPI units. Anyone with more TPI knowledge than me (which is a lot) please correct me on this!! You could ask the guys on the TPI board what the quickest way to access the EGR valve is.

Can you get your fingers under the plenum far enough to grab the EGR? If so stick your fingers under the EGR Diapraghm housing and you should be able to push on the diapraghm. It's a little tough to open and if yours is stuck open it may not push open any farther depending on how far open it is stuck. It's worth a try to see if it will open up or if by pushing on it will un-stick it. You could plug the EGR valve hose which should allow it to idle as a little test. You will get a 32 code though but should be getting one now anyways.

If you can't reach it go ahead and take the plenum off and then take the EGR valve off. The base will look different than the base on my TBI but similar. Then try the cleaning or just go buy a new one. The dealer may be a little pricey for the EGR than a local parts store would.

By the way, you can check your trouble codes with a manual for your car and a paper clip! Once plugged into the two proper pins in the ADL socket your engine light will flash out the trouble codes. I can't remember if it's the top, far left pins or the top far right pins that you jump across each other (VADER help here please), I haven't checked mine in a long time. The computer will flash a check code 12 (1 long flash followed by 2 short flashes) three times to let you know the computer is ok then flash each code 3 times and then repeat itself with the 12 code after all others have flashed. To clear the codes unplug the battery for at least 30 seconds and it will clear all stored codes.

[This message has been edited by badbird88 (edited September 28, 2000).]