EGR? i'm not sure...

hello all, i've been having a problem with my 94 olds 88 non supercharged 3.8 LSS with 160k mi.

first off, i need to know what part im looking at. its a round, cylindrical part with a 5 pin plug on top that has one hose connected to the exhaust manifold and the other routed in near the throttle body. the part itself is mounted in front of a radiator hose. is this the EGR valve?

if it is, is it OK to just unplug that? my check engine light doesnt come on, so fill me in?

here's the story: my car has been idling fine, and high rpm's are fine, but from around 1000-2500 RPM's the car has been acting jerky and acts like it wants to stall. (sometimes when decellerating it actually does stall). my car does this even after changing the fuel filter, sending unit (due to rust), plugs, wires, throttle position sensor, pvc valve and air filter. i've cleaned the mass air flow sensor, so that's unlikely.

today in my driveway it started acting up (the problem is intermittent, so it can't be mechanical) so i popped the hood and opened up the throttle a bit to make it run rough. i heard a hissing noise come from the (EGR?) when it bogged down, so i shut the car off and unplugged the unit, then turned it back on. let it run for a few mins then went for a 4 mile drive. no problems. seems as though that fixed it. coincidence or not? is it OK to leave it unplugged until i can afford to buy a new one?


i've tried to be as specific as i can, sorry the post is so long. i hope someone can at least tell me if i'm going to hurt anything. thanks in advance!!!

-rob

You could always take it off and clean it :)

It should be held on by two 10mm bolts, just remove and pop it loose. Spray the inside of the EGR valve and into the hoses that to lead to it with throttle body cleaner. Let this air dry for a couple hours and re-assemble.

ah its amazing how easy some things can be.. i'll do that sometime after i get out of work tomorrow.. do you think i should replace the "gasket" thing? i dont know about anyone elses, but mine just sort of flakes away when i touch it.


thanks!

-rob

Yeah, my gasket does the same thing....but I have just reused it as it seems to seal back fine. However, I (and probably you too) should replace it with a new one just to be on the safe side...but I'm poor and kinda lazy right now with three digit temps :(

well i sprayed eveyrthing with throttle body cleaner, didn't solve the problem. when i unhook the sensor the problem goes away, even though the check engine light comes on. i'll look into getting a new one, and meanwhile i'll keep an eye on my gas milage. i don't think it should go down at all, because it wasn't working in the first place... i've only gotten about 21 mpg since i've owned the car, which will be 1 year coming up in august. (i've been just "living" with the problem since i've had it... i've ignored it long enough. just think of all the money i could be saving at 3.03 per gallon!!!)

i drive about 240 miles every week at about 21 mpg. so.. 11.4 gallons of gas = $34.63.
if i drove 240 miles at the normal (26??) mpg, that would be 9.2 gallons equaling a total of $27.88,
saving me $351 dollars a year. ugh.

thanks for your help, alibi

-Rob

Dang, no luck on the TB cleaner, eh? If I recall right, a new EGR runs around $200-250. I was considering replacing one on a park avenue I had for a while (turned out to be a bad ECM) but the guy at Autozone told me that the electronic EGR's rarely fail.

Assuming yours has failed, you may be able to risk getting one from a junkyard, spray that down with TB cleaner, and try running that to see if it solves the problem. The risk is that you could end up with another faulty EGR, but if you trust the advice of the Autozone guy, then the odds with be with you that a junkyard one will be Ok.

Junkyard electronics are generally a no-no, but if you can find one for cheap enough, it could be worth a shot.

From your description of the problem, it does sound like the EGR is faulty, since the problem seems to go away when you unplug it...which I believe is the computer's way of using defualt settings in the event that the EGR has completely failed.

Do you have any stored SES codes? What kind of shape are the vacuum lines in?

well, im not too sure how to check for codes. i (think) my car is a transition year for the OBD systems, so it's pretty difficult to do without shelling out the bucks at a mechanics shop. i've read about the "tricks" for the OBD-I systems with the A and B pins and a paperclip, but i simply do not have those pins! it has the rectangular OBD-I style connector, but not the right pins. hmmm.....

as for the vacuum lines, many of them have been replaced, and the others look pretty good, except the little U shaped molded ones which have a few hairline cracks, nothing that would leak a vacuum though.

tomorrow i'll call some area wreck yards to see what they can do.

i'd rather not spend $250 on the car right away. i'm sure the engine will last, but i don't know about my frame! it's been a new york car its whole life :-/ such a shame to know that the engine won't reach its full 300,000+ life span. what a great engine.

Yeah, it is pretty sad that the engine will keep on chugging long after the frame has died of rot.

And yes, I think your car is one of the transition years. I'm not familiar with the transition, but there have been quite a few posts on the matter so you could try a forum search. You should be able to crop something up, and when you do try to get the codes before you go part-hunting, unless you happen across one for cheap....dang, if the part numbers were the same for my engine I'd just give you a spare I've got laying around but I don't know if the parts are the same--doubt it though.

Have you tried autozone? I know they will scan cars for free and you should be able to get the codes that way (assuming the tech is smart enough to know what you have with the transition and all). There are probably other parts store that do it for free too.