BIGTIME knock problems
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Registered User
Joined: Jan 2004
Posts: 241
BIGTIME knock problems
Friday, I finished putting the suspension in my car (mods in sig) and went out for a test drive. Seemed to run fine.
Got under the car and noticed a few things. My pass o2 sensor wire was touching the y pipe, so I tie wrapped it to the starter, to keep it up a bit.
Before I put the suspension in, I was getting some knock retard. During the suspension build I put in an lt4 knock module. Car is also tuned by madz28 for the setup.
Hour later went for a drive and going out of the sub, short shifted into 3rd (low rpm heavy load) and heard a banging. This banging sounded like the ujoints hitting the exhaust. Continued on ( I am now logging data) It would do it whenever I lugged the car in a high gear. Car went into closed loop. Drove on a few more minutes. Noticed that at part throttle I was feeling something, and looked over and was getting knock retard. What I was feeling was engine knock! IT surprised me it was so violent.
Looking at my data from datamaster, when I get the knock, my long term trends are all negative, some up to -15 percent. Could it be my computer is leaning out the system causing this knock?
I suspect my 02's . The one on the pass side is barely touching the flywheel housing. The one on the driver side did not thred in correctly and I could not get it out. I left it. It does not seem to leak but I am not sure. Looking at my data, the o2 values vary so much that I don't know if the values are ok or not. Any way to know?
If it is the o2's should the car run ok in open loop, maybe this would be a good check.
Also, any good souces on learning how to analyze this data?
thanks!
Got under the car and noticed a few things. My pass o2 sensor wire was touching the y pipe, so I tie wrapped it to the starter, to keep it up a bit.
Before I put the suspension in, I was getting some knock retard. During the suspension build I put in an lt4 knock module. Car is also tuned by madz28 for the setup.
Hour later went for a drive and going out of the sub, short shifted into 3rd (low rpm heavy load) and heard a banging. This banging sounded like the ujoints hitting the exhaust. Continued on ( I am now logging data) It would do it whenever I lugged the car in a high gear. Car went into closed loop. Drove on a few more minutes. Noticed that at part throttle I was feeling something, and looked over and was getting knock retard. What I was feeling was engine knock! IT surprised me it was so violent.
Looking at my data from datamaster, when I get the knock, my long term trends are all negative, some up to -15 percent. Could it be my computer is leaning out the system causing this knock?
I suspect my 02's . The one on the pass side is barely touching the flywheel housing. The one on the driver side did not thred in correctly and I could not get it out. I left it. It does not seem to leak but I am not sure. Looking at my data, the o2 values vary so much that I don't know if the values are ok or not. Any way to know?
If it is the o2's should the car run ok in open loop, maybe this would be a good check.
Also, any good souces on learning how to analyze this data?
thanks!
Registered User
Joined: Sep 2002
Posts: 1,158
From: Chicagoland Area
I had a similar problem with my car when i switched to PCMforless.
I had an LT4 knock module on my custom tuned car, but i wasn't happy with the programming so i went with PCMforless. I replaced the LT1 knock module in PCMforless's tuning with my LT4 knock moduel. However, Something was apparently severely wrong with the knock module, as it cost an immense amount of knock retard, so bad the car wasn't even driveable. I switched back to the LT1 knock module and didn't have a problem.
Not sure if that is exactly what ur problem is, but it would be one of the first things i would check.
I had an LT4 knock module on my custom tuned car, but i wasn't happy with the programming so i went with PCMforless. I replaced the LT1 knock module in PCMforless's tuning with my LT4 knock moduel. However, Something was apparently severely wrong with the knock module, as it cost an immense amount of knock retard, so bad the car wasn't even driveable. I switched back to the LT1 knock module and didn't have a problem.
Not sure if that is exactly what ur problem is, but it would be one of the first things i would check.
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