Knock sensor readings during a redline test

[cparke]

My knock sensors in group 20 go from all 0's at 4680 RPM's to all 12's from 4800 thru the 7000 at cut-off. After cut-off they all return to 0's. I've been told that might be an indication of too much timing? Could too much timing be responsible for a too rich condition?

[Nebone]

Looks like running rich is costing you power and fuel consumption. Running rich increases the time for the fuel to burn in the combustion chamber.

Knock probability is actually reduced when running rich due to slower burn, as the peak cylinder pressure is lower. On Block 20, the computer seems to be retarding 12 degrees which is VERY HIGH and indicates knocking. It is very weird since more fuel reduces cylinder knock.

You have a weird case there, and you shouldn't be florring your car to redline. You need to get a "working" MAF.

Another thing...I believe the Coolant Temperature Sensor "might" be the culprit. My buddy had similar issues on his 2.8 before and after replacing that sensor, everything was peachy.

[mike-2ptzero]

My knock sensors in group 20 go from all 0's at 4680 RPM's to all 12's from 4800 thru the 7000 at cut-off. After cut-off they all return to 0's. I've been told that might be an indication of too much timing? Could too much timing be responsible for a too rich condition?

12's? IIRC those will hit up to 25.

You need to read the CF corrections not knock readings.

[cparke]

Additionally info---the car is chipped. Supposedly chipping programs sometimes use timing to make more power.

[Ewok_Fetus]

Wish I was able to read something other than 0 in my block 20...

[cparke]

Looks like running rich is costing you power and fuel consumption. Running rich increases the time for the fuel to burn in the combustion chamber. Knock probability is actually reduced when running rich due to slower burn, as the peak cylinder pressure is lower. On Block 20, the computer seems to be retarding 12 degrees which is VERY HIGH and indicates knocking. It is very weird since more fuel reduces cylinder knock.

However, we also know that low MAF readings typically cause the engine to run lean. When the computer detects the system running rich, it reduces fuel all the time, which probably is the right thing to do for normal driving but during a redline test makes the engine run leaner than it already normally would due to the bad MAF, and that could cause this knocking?

You have a weird case there, and you shouldn't be florring your car to redline. You need to get a "working" MAF.

Well, I've never actually been flooring to redline, so my MAF test results (posted earlier in a separate thread) have all been bad. I was able to get up to 133 g/s from the MAF, but that wasn't through flooring.

I think we are saying now, to be safe, that I need to resolve the richness problem before I can look at the knock sensors. And I shouldn't try to do the redline test correctly anymore. Does that sound about right?

Another thing...I believe the Coolant Temperature Sensor "might" be the culprit. My buddy had similar issues on his 2.8 before and after replacing that sensor, everything was peachy.

Amazing idea. Is there any way to test this part?