Detonation problems
Thread Starter
Joined: Nov 2000
Posts: 1,022
Likes: 0
From: Newington, CT
Car: 88 IROC
Engine: 5.7 RamJet
Transmission: T56
Axle/Gears: Dana44 4.10
Detonation problems
1987 L98 TPI 159,000 miles.
engine temps - 180 - 200
good oil pressure
happens only when the car is warmed up and under moderate acceleration 3500 RPM +
timing is set to 5* advance
replaced knock sensor - no change
it is very inconsistant. I was assuming it to be due to carbon build from it being a high mileage engine.
However, the car does not see much use lately. Mostly goes out only on Saturday nights. Last week I drove it 2 hours to the track. Ran perfect the whole way there. No knock at all. Made three high 14 second passes with NO knock at all. Drove home 2 hours.. again no problems the car was perfect. I parked it and let is sit until the weekend. Saturday night.. three days later, the problem was there again. It never shows up until after the car is warmed up.. about when the t-stat opens. The engine compartment is very warm, but the gauge reads normal temps, and there are no signs of overheating, and no coolant loss so I believe the gauge to be reading fairly accurately.
Cap, rotor and wires are fairly new.
The car is unning rich because the exhaust manifold bolts keep coming loose and allowing false O2 readings. I am fixing that tomorrow, remove and clean manifolds, new bolts with lock washers. Could this be causing the problem?
I have not done anything with the ESC, but I really don't want to change it unless it needs it.
Any help would be appreciated. I want to know what is causing this before I pull the engine and rebuild so I am not chasing this with a new engine.
engine temps - 180 - 200
good oil pressure
happens only when the car is warmed up and under moderate acceleration 3500 RPM +
timing is set to 5* advance
replaced knock sensor - no change
it is very inconsistant. I was assuming it to be due to carbon build from it being a high mileage engine.
However, the car does not see much use lately. Mostly goes out only on Saturday nights. Last week I drove it 2 hours to the track. Ran perfect the whole way there. No knock at all. Made three high 14 second passes with NO knock at all. Drove home 2 hours.. again no problems the car was perfect. I parked it and let is sit until the weekend. Saturday night.. three days later, the problem was there again. It never shows up until after the car is warmed up.. about when the t-stat opens. The engine compartment is very warm, but the gauge reads normal temps, and there are no signs of overheating, and no coolant loss so I believe the gauge to be reading fairly accurately.
Cap, rotor and wires are fairly new.
The car is unning rich because the exhaust manifold bolts keep coming loose and allowing false O2 readings. I am fixing that tomorrow, remove and clean manifolds, new bolts with lock washers. Could this be causing the problem?
I have not done anything with the ESC, but I really don't want to change it unless it needs it.
Any help would be appreciated. I want to know what is causing this before I pull the engine and rebuild so I am not chasing this with a new engine.
Thread Starter
Joined: Nov 2000
Posts: 1,022
Likes: 0
From: Newington, CT
Car: 88 IROC
Engine: 5.7 RamJet
Transmission: T56
Axle/Gears: Dana44 4.10
it's the stock chain as far I know
------------------
Member of The Connecticut F Body Association
1987 IROC 5.7 - 14.72 @ 92
1988 Formula
1986 Z28
------------------
Member of The Connecticut F Body Association
1987 IROC 5.7 - 14.72 @ 92
1988 Formula
1986 Z28
Junior Member
Joined: Jul 2000
Posts: 76
Likes: 0
From: Sarasota
Ever loose any coolant, even gradually? Those small blocks have a tendency to loose head gaskets. Mine did. It lost coolant slowly and surely but it was another event that made me pull the head and I found out it was a SMALL leak, but there non the less.
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