EGR valves

[bigblock72]

Sometimes it's nice owning your own business, except when you have time to work on your own junk because there isn't any business coming in the door, which also means no money, which also means no paycheck.

I can relate, I'm either out in the shop working until midnight or later or I'm standing around wondering where the next house payment is going to come from. Self employment is definitely a double edge sword. After working for other crazy a$$ shops I'll gladly take the self employment though.

 

[dyeager535]

Yep, got it wrong.

Apparently these setups (at least in '91) are not looking for MAP sensor changes per se...looking for fuel integrator change when EGR is "shut off" by the ECM.

Conditions for ECM EGR testing: Vehicle speed over 50MPH. Engine vacuum between 15 and 55 kPa, no change in throttle position while test is run.

It does say you can ground the diagnostic terminal with key on, engine off, and test that the solenoid is allowing vacuum past it.I would guess there is a terminal on the ALDL, but the manual doesn't specify on this page. The SES light should flash when that terminal is grounded.

Lastly, it does mention that if the light doesn't flash with the terminal grounded, the "Quad-driver" may be have been damaged by the TCC circuit.

 

[4X4HIGH]

Ok, today i had my buddy print off the info from AllData on how to test the EGR system (which i had figured most of it out already) and the last test confirmed that the system is working properly. I still find it weird that with the EGR solenoid wiring unplugged it will not throw a code 32.

The info he gave me says "Code 32 will detect a faulty solenoid, vacuum supply, EGR valve or plugged passage. You would think that with the solenoid disconnected it would see a failure since it wasn't "in the system".

If anyone needs this info let me know and if i can get my scanner to cooperate with me then i'll scan it and post it here.

 

[dyeager535]

Your check engine light is working otherwise? That sounds like SOME sort of failure to me that the light won't trigger, you are correct that it should.

 

[4X4HIGH]

Yes the SES light does work as it comes on momentarily when the key is turned to the on position then goes out. Maybe Brian disabled the light on the chip i had in there? Now that i have a new chip installed as of last night i'll have to unplug the EGR solenoid and see if it will trip the SES light now.

 

[nsxxtreme]

I disconnected the EGR solenoid wire and drove about 8 miles under varied conditions and that did not turn on the SES light and i also checked by grounding the A & B terminal to verify that no code was set. So now i don't know if i have a problem with the ECM or not.

You might check with Brian but I think he does something that changes how the error codes get set. Before he reprogrammed mine it would throw a code and stay set for a while. Now if it throws a code it immediatley gets cleared.

 

[4X4HIGH]

Guess i forgot to update this post. I made all neccessary checks of the EGR system and they were all positive. I then made up a test light that i simply plug in between the EGR solenoid and the wiring harness so that when EGR is commanded this light will come on (which it does). I have ran with the EGR solenoid disconnected and that will not throw a SES light.

 

[dyeager535]

So it's working right as far as you know, just not triggering the check engine huh? Odd...

 

[RedBrute]

Just now read this post. I had a drivability problem about a year ago and posted my troubles in the fuel injection forum. I have a 12 mile drive to work and even with the EGR solenoid unplugged I would not always get a code 32. One evening on the way home I set the cruise and kept driving until my SES light came on... it was close to 20 miles before it triggered. Also I had a "NOID" light to check when the EGR solenoid was told to turn on thinking there was a PWM function. It appears ,as others have stated, that mine (an '87) is just on or off. Brians comment about leaving it on longer is puzzling, almost like he feels it is PWM? BTW my fix was another EGR, no smog out here (yet).