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How to clean the EGR valve - different year Northstars

193K views 75 replies 41 participants last post by  DrXtreme 
#1 ·
I recently purchased a 95 sts with 85,000 miles on it. Shortly after I got it, I noticed a wierd problem under light acceleration(around 1700 to 2300 rpms from a standstill). The acceleration is not steady. You can feel it and also watch the needle jump up and down slightly on the tach. What could be causing this and what should I do. I bought a warranty that covers drivetrain and engine stuff for 3 months or 3,000 miles and I am hoping to fix this under the warranty. Admittedly it is not that big of a deal, but it is annoying and I am wondering if performance could be better.
 
#27 ·
Re: How To Clean The EGR Valve

Wait a minute. "Mouse holes" are on '93/'94 Northstars. He has a 4.5. Mtflight, I believe you are thinking of the EGR "tubes" in the 4.9 tb bore.

That vacuum hose tailfin is discribing goes to the vacuum side of the EGR diaphram (no carbon there). Besides that, the pre Northstar EGRs rarely need cleaning.
 
#28 ·
Re: How To Clean The EGR Valve

Ranger said:
Wait a minute. "Mouse holes" are on '93/'94 Northstars. He has a 4.5. Mtflight, I believe you are thinking of the EGR "tubes" in the 4.9 tb bore.

That vacuum hose tailfin is discribing goes to the vacuum side of the EGR diaphram (no carbon there). Besides that, the pre Northstar EGRs rarely need cleaning.

Ahhh! I stand corrected. :)
 
#30 ·
Re: How To Clean The EGR Valve

I Am Reading Pcm;po171&po174 On The On Board Computer.my Problem Is Rough Idle Or Surging During Idle.what Does The Codes Mean.i Cleaned The Egr Valve But Only Used Carb Cleaner Around The Opening Of The Valve.how Far Do I Go?should I Push The Spring Loaded Valve Al The Way In?i Have A 2001 Deville.
 
#31 ·
Re: How To Clean The EGR Valve

P0171 - Fuel Trim System Lean Bank 1
P0174 - Fuel Trim System Lean Bank 2

Vacuum leak maybe.

Yes, press the spring loaded valve all the way in. It should move freely and not stick anywhere along its travel. Clean the shaft as well as the opening, but don't allow carb cleaner to run into the "can" as it can destroy the insulating varnish on the windings.
 
#33 ·
Re: How To Clean The EGR Valve

94CaddyConcours said:
Ok let me clarify or can you elaborate a little more. You want us to protect the canister by putting rag over it or by not spraying too much carb cleaner in the valve?
When cleaning the EGR, hold it in the upright position as it is when mounted. Holding it inverted allows solvent to run down the shaft and into the "can". That is what you want to avoid.
 
#34 ·
Re: How To Clean The EGR Valve

GUYS........Once you have cleaned the carbon chunks out of
that EGR valve install one of these GM linear clean screen
gaskets with a screen to keep the carbon build up out of the EGR
Best $7 bucks I have spent!

I have used them in my older GM vehicles..................

http://www.tomco-inc.com
 
#35 ·
Re: How To Clean The EGR Valve

I would not put that thing on my car on a bet. I can see the screen getting clogged and causing all sorts of drivability problems. The EGR passage is large enough so that it should never get plugged or need cleaning. That screen is not. That thing is a problem waiting to happen.
 
#36 ·
Re: How To Clean The EGR Valve

RANGER..........from all the posts I see here with clogged EGR valves
that gasket may well be a cure................

I used it successfully on my girls 4.3 Blazer which had many clogged
EGR issues because of the factory programming which didn't fully
open the EGR all the way thus causing carbon buildup and driveability
issues...............

My local indy repair shop now uses these screen/gaskets in several
different applications for older GM/Ford vehicles to cure carbon
clogged EGR issues..................

A good fix for $7 bucks IMO and experience and have NEVER had another
clogged EGR in her vehicle in the last 2 years!
Me thinks she need to BEAT on that vehicle a little to "clean" it out!
LOL!!!!!!!!!............geo
 
#38 ·
Re: How To Clean The EGR Valve

Hey Krashed989,

Thanks for the excellent post on how to clean the EGR Valve. I am a new caddy owner ('95 Seville SLS) and just pulled a few codes which brought me to this forum. (PO36 - PO39 - PO94)

THANKS!

edited: dont post questions in tech tips, please see sticky - urbanski
 
#41 ·
Re: How To Clean The EGR Valve

I kept getting PC1406 in my 96 Concours so I cleaned out the EGR valve today and it fixed it. Thanks again for the tutorial (I also used it ~40,000 miles ago). On the 96 Deville with the stainless steel fuel rail, I had to remove the manifold cover, unscrew the 4 bolts that hold the fuel rail down, pop out the fuel rail/injectors. After the fuel rail moves freely, then you can flex it enough to get access to one of the EGR bolts. I cleaned the EGR valve out with carb cleaner but the pintle was still sticking REALLY BAD. I then went to a wire brush...still sticking. I had my neighbor take a look and he used his flashlight to look inside. Around the rrim where the pintle valve sits closed (flush with the surface that touches the gasket) I had nasty carbon build-up. I had to use a flathead screwdriver to scrape out the carbon. After that, the pintle moved freely and my code is gone. Thanks again!
 
#43 ·
Re: How To Clean The EGR Valve

You better start working on cars and trucks to get an idea of just where fuel lines really run. The proximity to the top (not the exhaust side) of an EGR valve is the least of your worries !!
 
#45 ·
Re: How To Clean The EGR Valve

Does anyone have an issue re-using the gasket.
I've cleaned mine twice now and both times I had to go buy a new gasket b/c there was an air leak.
I even had to have my mechanic help me the first time and he said never to re-use the gasket. Anyone else having a problem getting a good seal?
Is there some special trick to it...?
 
#52 ·
Re: How To Clean The EGR Valve

Sorry, I can't tell by the last picture, where exactly do you spray the carb cleaner? everywhere but inside the allen ekey looking hole?
You can spray it in there just as long as you're careful not to get it into the big canister portion of the valve. The carb cleaner will eat away at the insulation on the electrical windings of the valve if it does go in that area.
 
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