no, shouldnt be open or making noise just sitting there, that could be your vacuum leak/engine trouble. try plugging the line before it goes to the purge valve, just not before the fpr, that would cause issues obviously. if you got a vacuum tester, i think the purge valve should hold vacuum with the voltage off to it on the side that goes to the canister.

thanks man. Hey, I gotta go look at it; so is the purge valve right on the unit? I know I saw some kind of solenoid on the canister with a wiring harness plugged in to it. Not too familiar with all of that. I don't have a vacuum pump/gauge.

Another thing I wonder about; could the CEL be on because the fuel pump relay is bypassed? That dk grn/wht wire between the PCM and the relay is now not doing anything; if I remember my relay logic that is probably circuit 86 and I would expect that it tells the relay when the engine is running, but is there any other loop going on there that might freak the PCM out? Looking at the only diagram I have, '97-up Regal, it looks like that is C1-8 at the PCM. I gotta solve this ASAP, thanks,

Mealmissing

purge valve if its like my 98 is on the engine to the right of the coils, looking from the front. should have vacuum from the throttle body that also feeds the fpr. it opens when the pcm calls for purge flow it opens drawing air/fuel vapor into engine. normally it should be closed though. the other line goes to the canister. on the canister is the vent valve. it opens and closes depending on if the pcm is asking to test the system.

i have never heard of a fuel circuit monitor. i guess they figured if the engine is running its working. the code is likely a evap code if there are issues with that. my bonnie has had evap codes almost constantly since i bought it 11 years ago. and no its not the same one

Yeah; I doubt the relay has any loop-back info for the PCM. My purge solenoid seems to be right on the canister; there was a wide-open vacuum leak in that line. Runs much better now but still sets the CEL on.

Unplug IAC with engine running, no change. Measure ohms at what I assume are A & B, 57 ohms. I think maybe that valve is bad, and I know that can set a code. I would like to test voltage but there are 4 wires all leading to the PCM and one of them has to be ground. I can easily short so I need detailed info before proceeding. Or I can replace the IAC, or try cleaning it?

Tested:
ECT; 2.65V cold, 2.22 warm, 2.02 hot
IAT, 3.35 cold, 3.29 warm, 3.03 hot.

IAT also had no ohms resistance cold. I think IAT should be replaced, and perhaps ECT. I'm sure at least the ECT could trigger the light. But I really think that IAC could solve this. Thoughts? Thanks for all of your awesome help,

Mealtogo

Sorry to get off track here Don, but what'* with all the "Mealtogo" and "Mealmissing" signatures?

Just trying to keep it light and see if anybody notices...which you did! I like to make fun of the fact that although I would like to think of myself as 'mealticket', a big baller, in fact that'* not the case...and I try to reflect the current state of affairs...I haven't worked in over 3 years and this attempt to flip the Bonnie needs to work...or else...so the 'meal' may not come if I don't get this smogged and sold for profit.

At the library now to see if they have better details on testing IAT, ECT, and IAC,

Mealmeal

I thought you were doing that to see if someone would notice. Cool beans!

Anyhoo...

Shoot; library has nothing. I really need the proper shop manual for this. Anybody know what wires I can backprobe on the IAC to test functioning? Also, anybody know the absolute voltage numbers for ECT and IAT? I saw a table somewhere online showing expected values at different temperatures and now can't find it. I really suspect that IAT voltage should drop lower but can't prove it. On a budget here,

'Mr. Meal to you'

There is a single ground (black wire) that is in the wire loom behind/under the ICM that is bolted to the engine part of the ICM bracket. Verify that it is there and connected.

Tomorrow is my Friday. If we are still working on this thread, I'll dig into my 1995 GM service manual and maybe scan some pages and post them. Just a word of caution though, these books are heavy and difficult to read/work with(I know, I only understand pictures) so if you see fire coming from my house, you'll know why.

Ha! Understood! Thanks so much, Mike. That'* solid of you. I may have a handle on it now. I either found the same table or something basically identical on the Autozone tech help page, although it'* ohms and not voltages with engine running like I would prefer...here is that link for anybody who may need it. You may need to sign up with a password but it'* free:

| Repair Guides | Electronic Engine Controls | Engine Coolant Temperature (ect) Sensor | AutoZone.com

Yeah; I will check that ground. Funny; there is an extra harness section in the trunk of the Bonnie which includes that ground you speak of with the ICM, and I think the crank sensor and I suspect the cam sensor plugs. --

Mealmaybe