Spark knock after long drives...
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Supreme Member
Joined: Apr 2002
Posts: 3,552
Likes: 5
From: New Jersey
Car: 86 Corvette, 89 IROC, 1999 TA
Engine: 350, 350, LS1
Transmission: 700r4, 700r4, T-56
Axle/Gears: 3.07, 373, 4.10
Spark knock after long drives...
hey im looking for some suggestions here, i've been having this problem for a while.. it seems after my car runs for over half an hour it starts to ping at high rpms.. i moved my fuel line farther from heat sources and it seems to have greatly reduced this... it runs fine and wont ping at all unless its been running for a long time... is there anyway to keep the fuel cooler or should i start playing with the timing? possibly think of a new way to route the fuel line? currently i have a regulator hanging by where the stock fuel line comes up on the drivers side with a rubber line going across to the carb.. could it be that its getting nice n hot becasue of the location and how it's routed above one of the headers and over top of the intake to the carb? any suggestions on how else i should route it? any ideas or suggestions are welcomed
Last edited by 89RsPower!; Feb 13, 2003 at 05:30 PM.
Supreme Member
Joined: Apr 2001
Posts: 1,516
Likes: 1
From: St. Catharines, ON
If I were you, I'd try using aluminum foil (shiny side out) in various places on the fuel line, where you think that heat is a problem.
If that helps your pinging, you have an idea of what's causing the problem, and where in the line.
If that helps your pinging, you have an idea of what's causing the problem, and where in the line.
Supreme Member
Joined: Sep 2001
Posts: 6,111
Likes: 53
From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
Yes move the fuel lines away from any heat source, like headers.
Hot fuel lines/ mechanical fuel pump will cause the fuel inside to boil.
The boiling fuel doesn't want to travel through the line to the carb. So the engine starves for fuel at high rpm/ load
when hot.
A pusher pump (electric) mounted at the back of the car will help too.
Check your total ignition advance too. should be 32 to 36
at high rpm with no vacuum advance.
vacuum advance should add 10 to 20 deg at high vacuum cruise.
You can step down one or two heat ranges on the spark plugs from stock if you have a generally heavy foot.
Hot fuel lines/ mechanical fuel pump will cause the fuel inside to boil.
The boiling fuel doesn't want to travel through the line to the carb. So the engine starves for fuel at high rpm/ load
when hot.
A pusher pump (electric) mounted at the back of the car will help too.
Check your total ignition advance too. should be 32 to 36
at high rpm with no vacuum advance.
vacuum advance should add 10 to 20 deg at high vacuum cruise.
You can step down one or two heat ranges on the spark plugs from stock if you have a generally heavy foot.
Thread Starter
Supreme Member
Joined: Apr 2002
Posts: 3,552
Likes: 5
From: New Jersey
Car: 86 Corvette, 89 IROC, 1999 TA
Engine: 350, 350, LS1
Transmission: 700r4, 700r4, T-56
Axle/Gears: 3.07, 373, 4.10
no egr system.. no electronic controls of any type.. mechanical advance dist.. i actually tried the aluminum foil method and it worked.. it looks kinda ****ty though... was wondering if there was a more perminante way to do it.. braided line? i cant really think of another way to route the fuel line or i would.. if anybody has any suggestions i'd be glad to hear em.. car was stock with v6 tbi i believe.. im using the electric pump that was in it with it regulated at 8 psi
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