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'95 seville sts
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Discussion Starter #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.
 

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2001 ETC Sequoia
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878 Posts
Re: 95 sts acceleration problem

Sounds like a noisey Throttle Position Sensor, but whatever it is it won't likely get better by its lonesome. Take advantage of that warranty and have it fixed properly.

Oh, and many happy miles. :)

Regards,
Warren
 

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94 Eldorado, and a 99 ETC
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3,887 Posts
Re: 95 sts acceleration problem

Sounds like a sticky EGR valve to me. Just give me a sec to copy and paste another post of mine here to help you...

here it is:

How to clean a sticky EGR valve

This article pertains to all models with the OBD-I Northstar 4.6L V8.

The symptoms of a sticky EGR valve are surging while trying to keep the throttle steady (not to be confused with surging at idle), and
code P036 (E036). Although it is possible to have a sticky valve with no code (that's how mine was).

First of all, don't do this job when the engine is hot. You WILL burn yourself. Your first task is finding the Exhaust Gas Recirculation (EGR) valve.
It is located underneath the spark plug wire cover near the rear bank of the engine. You will have to move the spark plug wire cover, you
don't have to completely take it off. Just lift it up and lay it sideways on top of the engine.



Now you need to unbolt the EGR valve. To do this, you will need a ratchet with an extension, and a 10mm socket.
Once you know the bolts are unscrewed all the way, don't try to remove them. Instead remove the whole EGR valve with the bolts still in the holes.
This will prevent you from dropping and loosing the bolts.





On the bottom of the valve you will see two holes, one that is plugged with what appears to be a screw and one that is open.
The screw like object is the valve. You should be able to press it in easily and when you let it go, it should close itself again (it's spring loaded).
The one I was working with was sticking in the closed position.




To clean the valve, simply spray carborator cleaner on and in the valve and wipe the dirt off with a cloth. Be very careful not to get it into
the canister, as the carb cleaner is a very powerful deturgent that will eat away the insulation on the windings in the sensor.
The following picture shows what you should not do.



The picture below on the other hand shows the right way.



Once you're all done cleaning the valve, you can reuse the gasket and put it all back together. Just make sure that when you put the
spark plug wire cover back into place that it clears the water pump belt.

What you have just done, should take care of your P036 (also E036) code. You can go into diagnostics mode and clear the code. If by chance it
didn't take care of the code (the code comes back after clearing it and going for a test drive), repeat the process.
If you can't get the code to go away, no matter how many times you clean the valve, replace the valve.

Happy motoring,
Krashed989
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Cadillac Owners Connoisseur
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1,164 Posts
Re: 95 sts acceleration problem

Great post, Krashed! Thanks very much... I assume this is posted in the Technical Tips section? <cough, cough> :thumbsup:
 

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Re: How To Clean The EGR Valve

Great Tip! The same process works on '96 and newer obd-II cars, you just have to move the fuel lines out of the way to get the EGR out. And the code on my '96 SLS was P1406. Thanks for the tips! Oh, its also a good idea to clean the carbon deposit out of the EGR supply and outlet tubes on the engine.
 

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1996 Cadillac Seville STS
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535 Posts
Re: How To Clean The EGR Valve

Great post and pictures..!

I know this sounds like a noob question...it actually IS a noob question, but I'm new with Caddys and car mechanics in general...so please bear with me....um....how exactly do you check for codes?? I have a 96 STS
 

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1996 Cadillac Seville STS
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535 Posts
Re: How To Clean The EGR Valve

Double post....i cant move the fuel lines out the way....how do u do it? im scared of breaking something...
 

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2010 DTS
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87,424 Posts
Re: How To Clean The EGR Valve

If you have had the fuel rail recall done, then you have a stainless steel fuel rail. There is no flex in it like the nylon rail. You must remove the rail and injectors.
 

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1996 Cadillac Seville STS
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535 Posts
Re: How To Clean The EGR Valve

I got it out of the way and cleaned it today...thanks to this post i got a clean EGR valve...
 

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Re: How To Clean The EGR Valve

If I was to put the EGR valve in carb cleaner overnight would it be ok? How about doing the same to the throttle body?
 

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13 Challenger RT, 11 CTS Coupe Premium, 94 Eldorado (RIP)
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1,306 Posts
Re: How To Clean The EGR Valve

It may be risky, but I do not see a problem with putting the egr valve in a pan of carb cleaner. Just make sure the level of carb cleaner does not go higher than the valve stem where the rubber boot is. It probably isn't good for the gasket though. However, when I remove my egr valve, the gasket stays on the engine. In Krashed's pics, his gasket is still on the valve.
 

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Re: How To Clean The EGR Valve

I've been watching this thread for awhile and the whole time I've wondered just how much could this part cost to justify all the work to clean it. Wow, was I surprised! $200 at the parts store alone, how much would it be at the dealer? I now have a copy of this cleaning procedure folded neatly into my factory service manual! Thanks!
lrry99eldo
 

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Re: How To Clean The EGR Valve

Great tip, but I see this cleaning tip is specific to the OBD-I Northstar 4.6L V8.
I have a 98 Eldo ETC. I believe that would fall into the OBD-II, correct?

I have similar gas pedal sticking problems and slight RPM movement when the car idles when cold.
Could this same tip be used to clean my EGR valve, or is it different on a 98-Eldo?

Thanks
Tim
 

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13 Challenger RT, 11 CTS Coupe Premium, 94 Eldorado (RIP)
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1,306 Posts
Re: How To Clean The EGR Valve

Your symptoms could have another cause. You might want to start another thread in the Eldo/Seville section.

As far cleaning the EGR valve goes, this procedure is the same for your year. Removal of the valve from the engine may be slightly different.
 

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96 sts
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Re: How To Clean The EGR Valve

I just recently bought a 96 sts and the guy had all the receipts from the all the work that had been done to it. He had a mechanic put on a new EGR valve and it costed about $250 (parts and labor).
Glad the previous owner put one in before I bought, saves me some dough.:cool2:
 

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94 Eldorado, and a 99 ETC
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3,887 Posts
Re: How To Clean The EGR Valve

Eldyfig said:
In Krashed's pics, his gasket is still on the valve.
Yes it is but I didn't document that I also changed the gasket afterwards. I changed it because that's actaully half of the gasket on the valve and the other half is still on the engine. The layers of it just split apart.

tkarlstad said:
Great tip, but I see this cleaning tip is specific to the OBD-I Northstar 4.6L V8.
I have a 98 Eldo ETC. I believe that would fall into the OBD-II, correct?

I have similar gas pedal sticking problems and slight RPM movement when the car idles when cold.
Could this same tip be used to clean my EGR valve, or is it different on a 98-Eldo?

Thanks
Tim
Yours is probably about the same, I just wasn't sure if the locations, or bolt patterns were different.

If your gas petal is sticking, you have a totally different problem. My gas petal has never been sticky, but when I tried to keep the gas petal steady to keep a pace up a hill, my car would surge instead of going steady. For me, the surging never happened at idle, but I'm not sure if it's possible or not for the EGR valve to cause suging at idle.

denscor said:
If I was to put the EGR valve in carb cleaner overnight would it be ok? How about doing the same to the throttle body?
Just remember that the objective is to keep the carb cleaner out of the canister. Otherwise it might eat away at the insulation on the windings.
 

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1999 White Diamond ETC
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2,540 Posts
Re: How To Clean The EGR Valve

I cleaned out the EGR valve. Man--removing it and installing it was a bear.

Although I don't have a steel fuel rail (recall only goes up to 1997), I have the metal bracket atop the EGR valve. I dropped a fastener (nut that fastens the metal plate to the top of the EGR valve) into the engine valley--and lost it.

My carb cleaner was misplaced--so I tried electronics cleaner and to my surprise a slurry of black water came out and the valve was squeaky clean. Nice surprise. The valve did not seem to be getting stuck before or after, but the shaft did have a lot of carbon deposits on it, which I successfully removed with the electronics cleaner and a small brush.

I scraped the old gasket off with a razor blade, and it was a bear all over again to put the EGR valve in, with that thick bracket in the way.
 

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XTS 13, Deville 99
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77 Posts
Re: How To Clean The EGR Valve

Man, I had alot of fun with my dad's 99 deville at 97k miles today. Symptoms: stall at low speed, misfiire P300 code, and surging on moderate/heavy acceleration. Heavy acceleration to 4000rpm would cause it to stall. No other code than P300. And my father babys the N*

Cleaned out the throttle body, and cleaned out the EGR valve. Both were filled with crap. On the 99 deville, there's no spark wire cover, but there's a different kind of headache, a bracket that attaches between the fuel lines and one of the EGR screws. Take the nut off, then gently push the fuel line away from the EGR to clear the bracket off that screw, then proceed to remove that screw.

After cleaning both TB and EGR out, topped out the gas tank (11 gals) of Shell 93, I went to a backroad and floored it. Problem solved... now I need to do a couple more WOT's before giving it back to the old man.
 

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Re: How To Clean The EGR Valve

My EGR valve has been causing a rough idle and stalling lately. I recently took it out, cleaned it with carborator cleaner and replaced it and now the vehicle won't turn over. It just keeps cranking. My question to Krashed989 or anyone else was: could this mean i messed up the EGR valve while cleaning it? I sprayed the carb-cleaner inside the two holes and put a paper towel in there to wipe out some of the carbon build-up... I didn't get any cleaner on the black electrical cylinder I don't think... Before I tried to clean out the EGR valve, the vehicle started and ran, though rough and with some stalling, but after the cleaning, won't start.
 
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