QZRBLU

I was coasting down a long hill and the SES light came on. Scanned as soon as I got home and found the 32 EGR code. All vacuum lines are good and plugged in correctly. I will go through the FSM prodcedures for diagnosing the Valve or the Solenoid as the culprit but does anyone know for sure how they detect EGR operation in a 1990 L98 engine? We don't have the temperature switch on the EGR pipe. Do they somehow measure the MAP value to see that the vacuum drops when the EGR valve opens? Should I be able to see that with a scanner (Snap ON) or (Diacomm)?
First, I will ground the Diag pin (B) to see if the EGR solenoid activates and holds/passes vacuum per the FSM.
Next, I will just put vacuum on the EGR valve to see that it pulls the pintle up. I'm still not clear how a Negative Backpressure EGR valve differs from our ECM-controlled EGR valve.

Mick

MrWillys

Mick,
This may be more helpful than the FSM:
http://www.chevythunder.com/egr_code_32.htm
The circuit is pretty simple. The criteria is meet in the ecm, and it sends a signal to the egr solenoid that allows vacuum to open the egr. Most likely the solenoid has failed, but it could be the valve itself. Good luck.

QZRBLU

Thanks Scott but, I have no temp switch, mine is a '90 and that chevythunder chart is for a MAF (84-'89) car. Helpful a little but
same pictures as the FSM.

Mick

red89c4

when my 89 did this i read on this forum and learned " if the code comes on emmediately after starting it is the solenoid, if it comes on after driving a while it is the valve." to check the egr valve apply vaccum to the valve and see if it will hold a vacuum, if not then it is bad.

QZRBLU

Red,
That makes sense.
Thanks,

Mick

Cliff Harris

Yes and yes.

vetteoz

http://www.motor.com/magazine/pdfs/122005_05.pdf

QZRBLU

That is a great article, a keeper for sure.

Thanks!!

Mick

speedycat3

Mick, I tried to respond to your PM, but your inbox is full.

Cliff Harris

On my '86 the ECM checks the EGR temperature switch when the ignition is turned on. If the switch is closed (meaning high temperature -- which is wrong at startup) the ECM will set error code 32 immediately.

When the ECM commands EGR by turning on the EGR solenoid, which then applies vacuum to the EGR valve, the hot exhaust gasses flowing through the EGR tube cause the EGR switch to close. If that does NOT happen the ECM will set error code 32. I think they should have used a different number, but we're stuck with that.

I don't know how the startup EGR check works on cars without the EGR temperature switch ('89 and later).

QZRBLU

I haven't been home to look at my 32 error but I found a great write-up today: http://tech.corvettecentral.com/2012...egr-diagnosis/

Mick

QZRBLU

I applied vacuum to the EGR valve today, engine off and the pintle pulls
out nicely and holds vacuum. Guess I'm going to check the solenoid next. Vacuum lines are good and not cracked anywhere.

Mick

91tpiman

Give me a call 302-212-8623

davewhtt

Just went through this last week with my 93. I changed the EGR valve and solonoid. So far so good.

BGZQ8

I think that the no temp switch started with the 1990 year.

QZRBLU

yes, my 90 uses the map and O2sensors to validate egr operation.

Mick

flyboyslc1

As stated above, I have replaced all vacuum lines, solenoid, and egr valve and still get code 32. I usually get the Service Engine Soon warning after I have been driving for 15 minutes or so. Sometimes it does not come on at all. I read somewhere, and it may be in one of the above links, that particularly on a 1991 if this still happens, it may be because of a carbon build up in the intake manifold, or plenum, or whatever it is called. So that is on my "to do" list for this winter.

The car still seems to run OK, with no noticeable decrease in fuel economy or performance.

steve

Just BOB

Have you tried clearing codes and seeing if the problem reoccurs? Sometimes you can have a "unique" set of circumstances that will trigger a code even when components are within spec and operating normally.

QZRBLU

Bob, Thanks,
I've cleared the fault and tested the EGR valve itself, it seems to hold vacuum and pulls the pintle off the seat. Tomorrow I will test that I have vacuum at the EGR valve with the solenoid disconnected and 2,000RPM. This car only sees about 3K miles per year so it might take a while to see another 32.


Mick

QZRBLU

I tested the EGR solenoid today following the FSM procedure and the solenoid is good too. Must have just been one of those random 32's that happen with a set of conditions I may never see again.


Thanks for all the suggestions.


Mick