EGR BYPASS QUESTIONS......

[wrd1972]

Hi, I got a 95 z28 lt1 six speed, obd1. A while back I was getting ses's and code 32's. I determined it was the EGR, I did not want to buy another new one so I bypassed with a block off plate on the back of the intake and it killed the ses's for a long time. The other day the ses came on again a couple of times and went back out.Is there anything else I need to do to eliminate the ses's associated with the egr valve. I guess its possible that the ses could be another code but doubtful. Also the engine runs great and has 70K on it.
Thanx
Bill

[Joe K. 99 Zeee!!]

Personally, I'd check the code out first before making an assumption. I've had mine come on at times and it turned out to be a blown fuse both times. Just because the engine runs great doesn't mean it has to be EGR.

[Injuneer]

Thye "EGR" code is set because the PCM does not see the expected "blip" in the MAP readings when it commands the EGR valve to open. By removing the valve, you've only made it impossible to ever meet the diagnostic.

What has saved you so far is the fact that the diagnostic in the OBD-I PCM's (93-95) is not very sensitive, and usually does not detect a missing valve. But it can, and sometimes does.

And as noted above, you can't just assume that because the SES light is on that it is DTC 32 again. Might be, and if it is, it makes sense, but why guess? That's what we accuse the dealer shops of doing.

It is also possible to "program out" the operation of the valve, limiting the times the valve would even operate, and it is possible to "turn off" the diagnostic.

[N20LT4Bird]

I sent my computer to Ed Wright and had the EGR "programmed out". The computer still looks at it but it does not trip the MIL. If I go in with the scanner, the EGR code is still there.