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Is that the culprit?Ive got a 1991 Caprice classic and I just had Dual exaust installed today and went to work and after work was leaving and the service engine soon light came on!!!Is it due to the new exaust or ( ? )Im taking it in to a garadge tomarrow and have the codes checked,I know I have a rattling tappit,but thats the only thing making any noise in my engine other wise its super quiet.Just courious if any one has any thoughts.
 
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Discussion Starter #2
The only direct connection I can think of between the ECM and the exhaust would be the O2 sensor. I assume you had it installed in one of the lines. Make sure it's tight.

Other than that, perhaps it's only incidental, maybe a wire or connection was not rehooked after the install?
 
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Discussion Starter #3
Oxygen sensor would be my guess as well, loose, unplugged....?

You can check the codes yourself, it's not a big trick. If you don't have one of the "fancy" $.29 "keys", jam a paper clip into the two top-right pins on the ALDL connector and watch the CE light flash the code at you. A code "12" means there's nothing wrong, it will flash once, pause, and flash twice, or, a code 12.
 
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Discussion Starter #4
It is a common problem. Code 32 EGR. the exaust now flows so well, that there is not enough backpressure to work the EGR properly.
 
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Discussion Starter #5
How is the dual exhaust set-up? (Decription from headers back).

Carlos
 
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Discussion Starter #6
basically where the mannifolds "y'ed" into the one solid pipe was cut sorter so there was 2 pipes exsposed,then new pipes were welded on and run to the new mufflers and out the back,The resinator is gone now also.No work was done to the o2 censor,he just sawsalled the old pipes at the y and ran new pipes.Ive got turbo mufflers I think he said.It was professinally done at a muffler shop and all the seams were welded to ensure no leaks were left behind.
 
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Discussion Starter #7
I had the same thing on my Roadmaster when I had straight pipes. When I put mufflers back in the check engine went away. Don't worry about it.
 
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Discussion Starter #8
i had no SES codes after i had my duals put on. if you have high mileage your egr might be giving in to age, and the problem might be coincidental. i occationally have the code 32 (egr) but wasnt related to my exhaust as i had it a couple times before they got installed. scan it and if its the infamous 32, replace egr and solenoid and that should do it.
 
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Discussion Starter #9
I got the same thing after I put dual exhaust on mine. The code 32 that I got flashing was because of the EGR not getting exhaust like it used to. That and it had about 170,000 miles on it(OEM EGR too). Mine has headers though, the way you describe it, you still have the original manifolds on it. I think they should still be restrictive enough for the EGR to work right. But when you get it scanned and it does show 32, just replace it like Lazy Destroyer said. Mine still comes on once in a while, but I haven't replaced it yet. I don't think it affects your engine. But don't take my word on that last one though. Laters...

Oscar
 
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MAN!!! you guys are like a online mechanic!!!!!!!!!!!!!!!!!!!!!!!!!!!,Well I took it too the autozone near me and its code 32.How much is a new egr gonna run me?(and soliniod),I have about 106000 miles or so.And does any one know FOR SURE if it will cause dammage,I already have a lifter to fix I dont want to let some thing else go bad that I could prevent.And how would changing the egr make the code go away,Or do I need to instal some other type?I mean one that accomidates dual exaust.Thanks a TON guys for putting my mind at ease!!!!!!!!!!!I was skerd!lol...
 
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Discussion Starter #11
Hey, i don't mean to "hijack" this thread, but i have a 91 LO5 9C1, (read POS winter beater) and it's CES light comes on from time to time (usually after i get into it) and i wonder how much a new O2 and EGR is?
also just a plain old paperclip in the connector under the dash?
thanks
jonathan
 
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Discussion Starter #12
yeah a simple paper clip will suffice.And if I can find one at a decent dicount store Ill let any one know.
 
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Discussion Starter #13
In general, and if I recall correctly, the EGR is supposed to do the following:

1. under steady cruise, it allows a small amount of exhaust back into the engine, via the intake manifold.

2. it is shutoff during idle.

3. it is shutoff during WOT.

4. it reduces certain types of emissions because it prevents the combustion from getting to hot (I know this sounds funny because you are adding hot exhaust into the intake --- and yet the end effect is not-as-hot combustion). The reason is that the exhaust gas slows down the combustion process because the air+fuel is diluted with already-combusted exhaust product.

5. in addition to item 4, it also allows very good highway fuel economy because it allows a lean mixture without nasty emissions nor pinging. So a healthy EGR system is good for your wallet. And you can live with the added intake heat during cruise --- and the EGR won't affect WOT at the track because the EGR should never come one (it's computer controlled).

Exhaust tends to be full of various gases plus some carbon. The carbon, over the life of the engine, tends to clog the EGR passages (even if you replace the EGR valve, the passages into the intake never get cleaned out). So as mileage accumulates, the EGHR passages get clogged and so LESS exahust gas gets into the engine. That means the EGR solneoid has to stay open LONGER so that the engine gets the exhaust gas it needs during steady cruise.

OK, so what happens when you alter the stock (& restrictive factory exhaust)? It means that there is less exhaust pressure feeding the EGR system, so that even if the EWR valve is open 100% of the time, you might not be getting enough exhaust gas into the engine during cruise.

I never mentioned HOW the engine knows that the EGR is getting pulled in. The answer is the MAP sensor. When the EGR valve is opened (via the EGR solenoid), exhaust is supposed to enter the intake. This causes a change in the pressure seen by the MAP sensor (MAP = manifold absolute pressure). So the computer expects to see a blip in the MAP when the EGR is ON. If it doesn't, it sets a code 32 which, in turn, turns on the idiot light on the dash. This is true for 89-93 TBI Bcars, as well as 94-96 Bcars.

So... what to do? Two things. First, use an EGR valve from a car having a lower restriction factory ehaust. 94-96 owners tend to use the Fcar EGR valve, because it's still intended for an LT1. pre-94 owners could opt for an Fcar EGR valve as well, for the same reason. They MIGHT also be able to use the same 94-96 Fcar EGR valve... but this is a guess on my part and I've no data to back this up.

Lastly, and this is hard to do --- clean out the EGR passages. This will help prevent the code 32 from being set, and it may also restore some fuel economy because ut allows the engine to run safely leaner.

FWIW. - Ken
 
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Discussion Starter #14
Sir I am in awe of your vast knoledge!!!!!

So please exscuse my complete ignorance, but...WHAT?could you tell me what to ask for when I got to pep boys for the replacement egr valve and or solinoid (sp?) and how would one go about cleaning out these passages you speak of?Thanks for your reply you showed me how little about the combustion engine I truely know.lol...
 
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Discussion Starter #16
<BLOCKQUOTE>quote:</font><HR>Originally posted by capricedriven:
....WHAT?could you tell me what to ask for when I got to pep boys for the replacement egr valve and or solinoid (sp?) and how would one go about cleaning out these passages you speak of?<HR></BLOCKQUOTE>

The fact that you want to go to Pep Boys and be at their mercy gives me pause. You've got a custom exhaust system so I can't just specify which EGR will work perfectly. As a starting point, and one that will probably work fine for you, would be to use a GM EGR valve for a LT1 4th generation Camaro/Firebird. And the best place to get one is from one of several discount GM parts dealers on the web. One is Dal at Vandevere and another is Chris @ Banks Chev (800-447-2107). There are others too.

As far as cleaning out the EGR passages -- I said it was hard because I've yet to meet anyone who has figured out how to do this with the intake manifold still on the engine. I can imagine how to do it but those ideas are best left to my imagination. With the intake removed from the engine, you need spary solvent, and some stiff wire to work through the passages. Solvent soaking probably would work even better. See, nothing about this is very easy.... and I believe (my $0.02, and it's my theory) that one reason why so many olrder model engines have persistent pinging is because the EGR system can't function properly due to arterial clogging of the EGR passages.

Sorry this isn't helping more.
 
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Discussion Starter #17
no, actually it helped out great.I got the main question answered that I needed.And as far as going to pep boys verses a dealership,they RAPE you around here for replacement parts and most auto dealers (parts stores) have the same gm certified product but alot cheeper.For example,I went to the berger chevy dealer here in G.R. looking for Impala ss RIMS, 200.00 PLUS each.!I got a quote for all this.And then the gm direct replacement grill,102.65,SO NO WAY IN HELL will I ever go to them.I have yet to check out Dal,I know he gets every one deals,In my eyes though he's still a GM parts dealer,which means Im not gonna get them parts at the same price i would if I were to look for the person (company) THEY buy from.Until I absolutly have to I probly never will deal with him simply because if I can find it cheeper I will.I dont have the top dollar to put into my car just to say "thats a GM direct replacement part on MY car whats "that" on yours?" Some people just buy the more exspensive stuff for bragging reasons.I like stuff to look good and be the right part for the right job but I cant justify paying more because it has "GM" stamped on it.
 
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Discussion Starter #18
AMEN!!
Some things only need to be good enough for who it's for. Plain and simple.

When I bent a rim last fall, I asked my buddies wife to check the replacement price for me since she works at the GM SPO here in town. They wanted over $300 for 1 rim! And, could you believe, they even still had some in stock. I wound up weaseling a new one through a local dealership employee for $60.
 
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Discussion Starter #19
I used to think the same way... And I got burned by cheapo auto parts store parts too many times. Believe it or not, GM parts are better quality than the Autzones and Pep Boys of the world. And by utilizing the Chris's and Dal's available to the forum, you will get good, quality parts, for usually LESS than the cheapo auto chain parts...

Oh, and the only place you can get GM parts is a GM dealer. You can't get them at the chain stores...

Just my $.02, but I think you may want to reconsider.
 
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Discussion Starter #20
I definately agree that, usually, you get what you pay for. I also wouldn't say to get everything where it's the cheapist - it all depends on the intent you have with the vehicle, how long you plan on owning it and the part you're replacing. All I meant was that most of the time you can't just run up to your local GM parts counter to replace ANYTHING that you need for your GM vehicle without taking it in the chute. Dal and Sam seem to be exceptions for us - but they are just that - exceptions to the rule.
 
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