LS5 WOT detonation under load
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 751
Likes: 0
From: Chandler AZ
St. Jude Contributor
LS5 WOT detonation under load
Ok here is the problem
1. At WOT under load only I get detonation.
2. Engine just rebuilt
3. Carb just rebuilt
4. Distributer just recurved
5. Just checked plugs and they are fowled (gap .035)
6. Have minor vaccum leak
Where the hell do I start to de-bug?
Vaccum problem
Fuel delivery problem
Timing problem
I plan to plug the manifold and put new plugs in.
Next verify timing at idle.
Next run it under load and monitor fule presure.
Since I dont have a Dyno or air/fuel Co2 equipment am I attempting to tune this without a hope?
All I want is a safe operating point not neccesarily the ideal tune................
Your comments welcome.
1. At WOT under load only I get detonation.
2. Engine just rebuilt
3. Carb just rebuilt
4. Distributer just recurved
5. Just checked plugs and they are fowled (gap .035)
6. Have minor vaccum leak
Where the hell do I start to de-bug?
Vaccum problem
Fuel delivery problem
Timing problem
I plan to plug the manifold and put new plugs in.
Next verify timing at idle.
Next run it under load and monitor fule presure.
Since I dont have a Dyno or air/fuel Co2 equipment am I attempting to tune this without a hope?
All I want is a safe operating point not neccesarily the ideal tune................
Your comments welcome.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Hey Ron, we are firming up Oct 2 for a get-together
tech/work session in Hudson. The main attraction will be
a front suspension rebuild, but there should be some people
willing to help tinker with your vette.
First thing to do is verify the timing curve.
Next, running with a vacuum guage during operation is easy.
Once this is checked, I'd move on to fuel/carb issues.
Fouled plugs ? sticky black with oil ? Any significant vacuum leak
would make it run lean and burn the plugs up rather than foul them.
Lemme know if you want to make it on Oct 2. Otherwise, I will
be pretty busy with my own vette - trying to get her on the road.
It's only been about 4 years.
tech/work session in Hudson. The main attraction will be
a front suspension rebuild, but there should be some people
willing to help tinker with your vette.
First thing to do is verify the timing curve.
Next, running with a vacuum guage during operation is easy.
Once this is checked, I'd move on to fuel/carb issues.
Fouled plugs ? sticky black with oil ? Any significant vacuum leak
would make it run lean and burn the plugs up rather than foul them.
Lemme know if you want to make it on Oct 2. Otherwise, I will
be pretty busy with my own vette - trying to get her on the road.
It's only been about 4 years.
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 751
Likes: 0
From: Chandler AZ
St. Jude Contributor
Hi Dave, Yup black pligs from a rich engine is what I found. I will check the vacuum and fuel presure and timing this weekend.
I should be in town OCT 2 and if I am count me in.
Thanks,
Ron
I should be in town OCT 2 and if I am count me in.
Thanks,
Ron
Safety Car
Joined: Aug 1999
Posts: 4,862
Likes: 118
From: Texas
Because your detonation is occuring at WOT, the first thing you should verify is the final timing at over 3,000rpm. You'll either need to install a timing tape on the torsion damper or use a good adjustable timing light. Start out timing the distributor so that you have 36-37 degrees BTDC total timing.
