91superram

I think my EGR valve has been sticking because I got a code and I have also
noticed once and a while (when stuck) a lack of power.Can I just disconnect
the vacuum line and will it be in the right postion that It will not effect my performance?

tjwong

If you disconnect the vacuum line you will still set a code. The ECM knows when the EGR is suposed to be open and it uses either the temperature switch or the MAP sensor to tell it that the EGR is working. When the EGR valve opens the temperature switch closes and the ECM sees this input. If the EGR is commanded to open and the temperature switch don't close it sets a diagnostic code 32 if I remember right. Disconnecting it won't affect performance but you will see an annoying check engine light.

Even if the EGR works, the passage could be plugged and would cause the same problem. The other way the ECM can tell is my a differential in MAP measurement when the EGR is commanded on. This is how the ECM knows in the newer cars and trucks that uses a EGR valve. Later when GM started using a modulated solenoid the ECM does a electrical check across the solenoid. It knows if there is a open circuit or a shorted solenoid and will also set a code if this event is seen. In the 94 and up that uses an EGR valve with a PWM solenoid the PCM monitors the electrical circuit of the solenoid. It also monitors other solenoids and relays such as the EVAP system and the AIR system.


[Modified by tjwong, 7:59 PM 9/13/2003]

oldace84

ECM codes?
thanks
tony

tjwong

32 is the code for EGR

91superram

So to get this right if I disconnect the vacuum line I will get a code but my cars performance will not be affected

tjwong

I beleive that is true you will set a code 32 but it should not affect runing of the car. I had a truck I worked on and that was the problem, a faulty solenoid caused a code 32 in a 94 truck, other than the code it ran fine.

BookSmart

Be careful if you EGR is stuck open it will not help to un-plug the vacuume line.

I replaced my EGR easily in a afternoon. It was $50 and all you have to do it take the upper intake off not the runners. There were 2 benifits of the EGR replacement. My check engine light went off and my car actually ran cooler. :yesnod:

SunCr

EGR reduces combustion temps. Run without it and you up the chances of detonation. In response to the knock signal, the ECM pulls out timing and performance goes down.