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2005 White Diamond STS N* 1SF RWD ACC/HUD
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Discussion Starter #1
The motor in my car pings and I just would like to know where to start as far as curing this condition. I am using top tier premium gasoline with an octane rating of 92. The pinging seems to come with any sort of acceleration heavy or light. Any suggestions?
 

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2005 White Diamond STS N* 1SF RWD ACC/HUD
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Discussion Starter #2
Well, I did a search AFTER posting this thread :banghead: :banghead: :banghead: and found that replacing the EGR valve and gasket may very well fix my problem, so I will try that. Sorry for not searching first...:hide:
 

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76 Eldo (54k), 76 Eldo (52k), 78 Eldo (9k), 85 Deville (43k)
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668 Posts
First thing first--and something that's easy...clean out the EGR tubes under the throttle body plates in the intake manifold. Use some intake cleaner and spray down into the tubes and scrape a coat hanger around in there. They may be very plugged.

Also, after the car has cooled, try pushing on the EGR Valve diaphram on the underside of the valve. If it doesn't move freely, you need to replace it.
 

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2005 White Diamond STS N* 1SF RWD ACC/HUD
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Discussion Starter #7
I'll check and clean the EGR tubes first. I believe I read somewhere that the timing can be adjusted or checked via the DIC...is this correct?
 

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93 Sedan Deville 4.9L
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timing is checked with a timing light and changed by moving the distributor, The DIC can show timing advance, not sure what its good for though.

Make sure to jumper the pins in the ALDC, forgot which ones to do though.
Start with the egr diagnosises above
 

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76 Eldo (54k), 76 Eldo (52k), 78 Eldo (9k), 85 Deville (43k)
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You will need a timing light to check the timing, but this is probably not your problem. Clogged/inoperative EGR systems are the main cause of pinging.

The DIC timing indicates what value a timing light should give if used...if the base timing is set incorrectly, then the DIC will be off.

Stay away from the timing for now. Almost all 4.9 pinging problems are due to EGR issues.
 

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93 Sedan Deville 4.9L
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Yeah, Start with egr, t is pretty easy. One thing i forgot to mention was to check vacuum hoses too. IF the vacuum lines are original they are probably on their last legs almost 20 years later
 

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2005 White Diamond STS N* 1SF RWD ACC/HUD
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Discussion Starter #11
Thank you all! I probably won't be able to get to this until later in the week, but I certainly appreciate the help. Intake cleaner was mentioned to use to clean the EGR tubes. I don't think I have ever seen the stuff (but have never looked for it either). Would throttle body cleaner work? And the tubes were said to be under the throttle body plates...do I just hold them open and clean, or does the throttle body need to come off?
 

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93 Sedan Deville 4.9L
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Throttle bod cleaner, carb cleaner and a few other cleaners will work, Doesnt really matter that much. I just used carb cleaner in an aersol can since i had it already.

You can keep them open by removing the air filter housing and either holding the gas pedal to the floor with a brick or assistant; Or just hold the throttle cable open under the hood. All with the engine off of course.

While your at it go ahead and clean the blades on the throttle body, especially the bottom and sides, also get the sides of the throttle body on the inside.

Dont worry if junk falls in the tubes, itll burn up.
 
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