94 Olds Cutlass Perplexing EGR Problem?!?

Newbie here having an EGR problem that has me stumped :screwy:

94 Olds Cutlass Supreme SL, 3.1 V6 Code 'M', 58K miles

Out of the blue car lost all power and stalled trying to make it up hill at work. I managed to get the car into the parking lot after numerous stalls/restarts.

Engine idles very rough and I can visibly see and hear exhaust blowing out from under gasket that is actually part of the EGR valve itself - under the standoffs and plate right above base of valve.

I removed the EGR, cleaned and re-installed - same problem. I assumed (?) the valve was bad so I installed new valve/gaskets - still same problem.

I have no Check Engine Light (and of course can't read the codes myself anyway because of the way GM blocked out owners from scanning this year). There is visible black soot on the rear bumper right above the tailpipe that wasn't there before.

Don't have a manual to check for proper voltage at EGR electrical connector.

If I manually advance the throttle from idle while car is running the engine will stutter - stutter increases and worsens as RPM's climb - until the car finally stalls.

Almost seems as if the exhaust coming thru the pipe from manifold to EGR is building up inside the EGR valve cavity itself and finally blowing by the plate under the solenoid pintle springs due to high pressure.

Is the EGR supposed to be open somewhat no matter what engine speed? I always thought that they only opened on Cruise and if open during idle, would make the car exhibit the power/stalling problems I have.

Only other thing I can think of is if the cat was plugged (or almost plugged) and the exhaust was not flowing freely thru the exhaust - but up to the EGR valve instead and building up too much pressure - this excessive backpressure on exhaust may also be the cause of loss of power, stuttering, and stalling?

NE1 else ever have similar problem? Have any ideas where I should go next?

Any help would be greatly appreciated!

TIA,
-Jay-

sounds like it is coverter...or you might check gas filter..but really sounds like converter..good luck


SCRAPPER...

Guess there's really no way to check converter flow other than at tailpipe? Cause there could still be some flow if it is only partially plugged.

Hate to cut it out and replace unless that's the actual problem...

its the cat. there will always be SOME flow as long as the car is able to run. but it really does sound like the cat. if you can, you can try to disconnect it at the Y pipe but those bolts are usually rusted.

another thought, this will still restrict flow alot and only to be used as a diagnosis, but why dont you try to remove the 02 sensor and see if it clears up.

Well, got the car started again - seems to be ample exhaust coming from the pipe - but that is of course subjective. Car is stuck in parking lot right now so getting it up off ground where it sets to disconnect cat is probably out of the question - it would have to be towed somewhere.

I did notice that the pulsing of the exhaust gas that is blowing by the EGR valve coincides with the firing of the cylinders - but again that could be just due to plugged exhaust.

Good idea on removing O2 sensor to open up a little more hole in exhaust - that I can get to alot easier.

This car was a handme down from grandma for my daughter. It did have a blown head gasket at one time and she drove it with coolant in the oil. Engine was flushed, rad flushed and new gasket installed but I have no idea whether they resurfaced the head at replacement - and she can't remember anything + no records. I'm going to check manifold vacuum also to make sure pressure is not coming from intake side of EGR valve.

Fuses all check out fine. I removed electrical connector from EGR and it made no difference - car ran the same. Upon probing the connector I found 13v between center post and bottom post of 'Y' ONLY there was no voltage present between center post and either of the posts on left or right leg of 'Y' - course I don't know if there is supposed to be - that would mean that all (3) solenoid pintles are open during idle - which would dump a ton of exhaust gas back into intake - I wouldn't think the car would run well with that much dilution at idle...

Rn it with no egr, that tell you if the exhaust is blocked, if so watch the muffler, pieces of the cat can wind up in there also.

I take it that when you say run it with no EGR that you mean to remove the valve entirely and install block off plate?

No, run it so the exhaust can come out the egr port, if it clears up any of the problem then you know it is a blocked exhaust issue, just be careful as you don't want exh. flying around the engine compt too long!

Gotcha :iceslolan

Thanx for all the help guys