Cant get rid of pinging!!!!
Thread Starter
Senior Member
Joined: Dec 2000
Posts: 914
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From: Hampton Roads. VA
Cant get rid of pinging!!!!
A few monthes ago I heard my 91RS was knocking, my girlfriend drives it and she hadnt noticed it yet. I made a switch over to premium and it went away. Well, its doing it again and I cant figure it out! I just checked my timing and its at 4degrees which is to advanced but it shouldnt be enough to make it knock.
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We are the future, the 21st. century dislexyic, glue sniffing, cyber *****, with homicidal minds and handguns.
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We are the future, the 21st. century dislexyic, glue sniffing, cyber *****, with homicidal minds and handguns.
TGO Supporter
Joined: Aug 1999
Posts: 14,811
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From: Jackson County
change your timing and see if it improves. also make sure the est is working
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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM
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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM
Moderator
Joined: Jan 2000
Posts: 19,651
Likes: 309
LBC,
What Ed said.
If that doesn't uncover any problems, you might be running too hot in the chambers, have hot spark plugs, running too lean, have a dysfunctional EGR, or are accumulating carbon deposits in the chambers.
Check the mixture with a scanner if you can. Make sure the cooling system is circulating through the heads well. Check the spark plug heat range. Check EGR operation. Make sure there are no vacuum leaks, including the PCV and brake booster. GM Top Engine Cleaner can help clean the deposits, or a judicious application of injected water can clean the chambers fairly well.
The newer MTBE fuel formulations can leave chamber deposits, not unlike what us "old farts" used to struggle with when running tetraethyl lead additives. Can you get ethanol blends in your area? It might be worth a try. I've been getting my engines "drunk" on a daily basis since the late '70s and they are cleaner than I've ever seen with plain oil hydrocarbon fuels. They also suppress knock fairly well, since they burn a bit cooler.
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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader
What Ed said.
If that doesn't uncover any problems, you might be running too hot in the chambers, have hot spark plugs, running too lean, have a dysfunctional EGR, or are accumulating carbon deposits in the chambers.
Check the mixture with a scanner if you can. Make sure the cooling system is circulating through the heads well. Check the spark plug heat range. Check EGR operation. Make sure there are no vacuum leaks, including the PCV and brake booster. GM Top Engine Cleaner can help clean the deposits, or a judicious application of injected water can clean the chambers fairly well.
The newer MTBE fuel formulations can leave chamber deposits, not unlike what us "old farts" used to struggle with when running tetraethyl lead additives. Can you get ethanol blends in your area? It might be worth a try. I've been getting my engines "drunk" on a daily basis since the late '70s and they are cleaner than I've ever seen with plain oil hydrocarbon fuels. They also suppress knock fairly well, since they burn a bit cooler.
------------------
Later,
Vader
------------------
"What a Day..."
Adobe Acrobat Reader
Thread Starter
Senior Member
Joined: Dec 2000
Posts: 914
Likes: 0
From: Hampton Roads. VA
The EST is working. The PCV valve does need to be changed also. I'm going to readjust timing tommarow. Could fuel injector cleaner cause carbon build up? How does water break down deposits? The o2 sensor is reading a good mixture also. I don't know what to do!!!
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