88 GMC with code 32

[thinger2]

Went out this morning and did manage to get the EGR valve off without in problems. I tested the solenoid with 12 volts and it clicked so I assume it is functioning properly. I tested the solenoid plug for volts but did not detect any voltage by just turning the key on. Based on everyone’s description of when the solenoid usually operates I didn’t really expect to see any voltage but decided to make the test anyway. I did attempt to test out the EGR valve itself. I hooked it up to a good valcuum source on another vehicle and could not detect any movement. I could actually suck on a hose connected to the EGR and draw air, very much restricted but I could get air. Does it sound like the EGR valve is most likely the source of my problem? I would appreciate everyone’s thoughts on what I have determined so far with my testing. Is there other tests I should make before I get a replacement EGR valve? Thanks,

A stuck egr valve will not move under any engine vacuum source.
You will never suck it open.
It might be bad but it might just be carbon crudded.
The reason to try to save your old EGR valve is that the new ones are absolute garbage.
You can clean a stuck egr valve if you are very carefull about it.
The manifold side of the egr diaphram will have a ring of carbon the prevents the diaphram from seating properly
And some of that carbom will leak past and crud up the seal making it all stick in place.
Soak the egr in brake clean or carb cleaner or whatever your solvent of choice.
After it soaks for a long time.
Stick your fingers in the holes and gently push on the outer rim of the diaphram.
Do not touch the diaphragm
If it doesnt move at all.
Soak it some more.
The idea is to get the inside of the egr clean enough the the diapragm can move through its entire travel.
I bet it is stuck in place.
If you can get it to start moving, get a "mighty vac" kit
About 40 bucks and a very usefull tool to own.
attach the mighty vac to the vacuum port on the egr valve and see if it moves.
About 12 inches of vacuum wil tell you the whole story.
If you can move the diapragm through its entire travel and the spring returns it to its normally closed position but it will not hold vacuum?
It has a hole in it.
If it will hold 12 inches and doesnt bleed down you can hold that diaphragm open under vacuum and carefully scrape the carbon ring off of the inside of the housing.
A dirty carbon stuck egr will always fail a vacuum test.
Because the carbon buildup keeps it from sealing.
I am at about 270k on the factory EGR valve.
But. I also pull the tbi every year and I do the all of the sensors inputs and normal cap rotor plug wires twice a year.
Because of 10 percent ethylated gas and chinese parts and at some point I will loose my mind and get arrested at the Advanced Orielly Napa Zone when they tell me that there is no such thing as anti-seize compound.
Yep. That happened.
Save your trucks and save your parts and stockpile the OEM stuff whenever you can find it.
Im getting old and Im starting to see a future where us old guys get sent to prison becuase our motorized wheelchairs stopped working and we choke people while screaming "Its the Grounds you dense turd"
"Its the Grounds"

 

[Schurkey]

I hooked it up to a good valcuum source on another vehicle and could not detect any movement. I could actually suck on a hose connected to the EGR and draw air, very much restricted but I could get air.

A stuck egr valve will not move under any engine vacuum source.
You will never suck it open.
It might be bad but it might just be carbon crudded.

Based on his description, it's not stuck, the diaphragm leaks.

If the diaphragm does not hold vacuum, the EGR valve is done.

 

[thinger2]

Based on his description, it's not stuck, the diaphragm leaks.

If the diaphragm does not hold vacuum, the EGR valve is done.

Yep. but if it is stuck it wont hold vacuum.
I think it is worth the effort to attempt to free it up and then try to pull vacuum and maybe work it back and forth to see if it will hold.
I have had pretty good results but it takes a lot of calm and zen to do it.
Before I take a part to Nueremburg I always buy the spare.
But I always try to give cpr to the original part and keep the aftermarket part as as a backup.
I know that everyone should have a scanner and now how to use it.
But, when your truck just shuts off on a dark highway in the middle of noplace with your wife holding an entire roasted turkey on her lap during a monsoon rain storm you are way beyond theory.
I think that half assed road side repair is a valid approach to get these trucks running even if it is a short term fix.
Sometimes we are talking to people who need to go to work tomorrow so they can pay the rent and feed their kids.
These trucks are still working man trucks for a lot of people.
We really dont want to be frosted hair clean finger nail hair poofed elitest truck gate keeping auction rpo code one of one ********** do we?

 

[Schurkey]

Did he not already state that he could draw air though the EGR valve? Which would then mean that the valve does not hold vacuum. A negative-backpressure valve should hold vacuum. A positive-backpressure valve might not. And the old-style valves that did not sense backpressure also should hold vacuum.

I don't see how a stuck--or not stuck--valve makes a difference if the thing does not hold vacuum/leaks air. Even if you free it up so it's no longer stuck...the diaphragm is still junk.

 

[OldBlue_88]

I purchased a new EGR valve and got it installed. It was Advance Auto Parts part number EGC1114. The actual part did have a N stamped on it and as near as I could compare the two they are a match. So far I’ve only taken it for a short test drive, but it seems to run fine and I didn’t have any warning lights, so I assume that if I didn’t fix my problem at least I didn’t cause any new ones. I suppose I’ll just have to wait until I need to get it out on the highway to decide whether I actually fixed it or not, but with gas prices as they currently are I’m not just going to go riding around simply to test it out. But everything does seem okay with it at this time. Oh, I did hook power back to the solenoid and when powered it did open up to allow air to pass but not when power was removed. I do appreciate everyone’s help and I’ll try to post back at a later date with how things are going with it. Thanks,

 

[someotherguy]

Do yourself a favor and just go read the code 32 troubleshooting flowchart in the factory service manual. You'll learn something about how the computer tests the EGR valve. Then you'll know what type of driving will lead to the test being run so you can know when to expect confirmation of a successful repair.

Richard

 

[thinger2]

Did he not already state that he could draw air though the EGR valve? Which would then mean that the valve does not hold vacuum. A negative-backpressure valve should hold vacuum. A positive-backpressure valve might not. And the old-style valves that did not sense backpressure also should hold vacuum.

I don't see how a stuck--or not stuck--valve makes a difference if the thing does not hold vacuum/leaks air. Even if you free it up so it's no longer stuck...the diaphragm is still junk.

The ring of carbon buildup will make the diaphragm stick throughout the radius of the diaphram.
When you spray solvent into the egr that crud breaks apart in chunks and makes the problem much worse.
Pull the egr valve.
Turn it upside down and soak it
Fire hose that egr with brakeclean
If the egr doesnt have a hole in it, it is stuck on that carbon ring that forms in the housing.
The only way to figure out if it has a hole in it is to clean the diaphragm enough so that it can move and then see if it will hold a vacuum.
That may seem like a pain but it is much easier than trying to make an aftermarket chinese egr work.