Seeing 10+ degrees of KR; torque converter related?
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From: Glendale, AZ
Seeing 10+ degrees of KR; torque converter related?
Here'* the history of the problem:
After my engine modifications (cam, high compression heads) and EGR delete back in November '05, I was seeing high levels of KR at high load, light throttle conditions. We attributed the problem to my EGR delete and assumed the combustion chamber temperatures were too high without it, causing KR while cruising. MyLittleBlackBird and I reinstalled the EGR valve a little over a week ago, and I just had my first scan since that time. I was surprised to find out that I am still experiencing the same KR readings under the same conditions, despite the fact that the EGR seems to be functioning normally.
It is important to note that this all seems to be false KR. It only occurs when the torque converter locks up. Low RPM acceleration through first and second gear shows no KR readings, and even the shift to third gear is knock-free. However, the numbers spike up when the TC locks in third gear, jumping from 0 degrees to at least 4 or 5, with readings of 10-12 degrees in places. This is completely mystifying, but seems to show a correlation between TC lockup and false KR. There are no issues at wide open throttle or high load conditions in 1st and 2nd gear, only in 3rd and 4th with the converter locked.
I don't understand any of this, and I can't think of anyone else on these forums who has had a similar problem. Keep in mind that I do have trouble with the notorious 1997 TC surge/chuggle in warm weather, which only occurs under TC lockup with similar high-load conditions. I'm wondering if the chuggle and false KR readings have anything in common (i.e., tranny problems or bad torque converter). I will be in Intense'* shop on April 14th so I can have them diagnose some of this stuff if necessary, but any ideas are welcome. Ask me anything that will help narrow down this issue! Thanks!
After my engine modifications (cam, high compression heads) and EGR delete back in November '05, I was seeing high levels of KR at high load, light throttle conditions. We attributed the problem to my EGR delete and assumed the combustion chamber temperatures were too high without it, causing KR while cruising. MyLittleBlackBird and I reinstalled the EGR valve a little over a week ago, and I just had my first scan since that time. I was surprised to find out that I am still experiencing the same KR readings under the same conditions, despite the fact that the EGR seems to be functioning normally.
It is important to note that this all seems to be false KR. It only occurs when the torque converter locks up. Low RPM acceleration through first and second gear shows no KR readings, and even the shift to third gear is knock-free. However, the numbers spike up when the TC locks in third gear, jumping from 0 degrees to at least 4 or 5, with readings of 10-12 degrees in places. This is completely mystifying, but seems to show a correlation between TC lockup and false KR. There are no issues at wide open throttle or high load conditions in 1st and 2nd gear, only in 3rd and 4th with the converter locked.
I don't understand any of this, and I can't think of anyone else on these forums who has had a similar problem. Keep in mind that I do have trouble with the notorious 1997 TC surge/chuggle in warm weather, which only occurs under TC lockup with similar high-load conditions. I'm wondering if the chuggle and false KR readings have anything in common (i.e., tranny problems or bad torque converter). I will be in Intense'* shop on April 14th so I can have them diagnose some of this stuff if necessary, but any ideas are welcome. Ask me anything that will help narrow down this issue! Thanks!
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I'll make the assumption that you are running 93 octane fuel...
I forget how much you managed to raise your compression by when you shaved the heads... Was it 10.1 : 1 or 10.3 : 1 ?
So the KR is only happening under Load when the TCC is locked... With your compression and new cam could the TCC be locking at too low of a road speed being that you have brought up your compression and your bit more bumpy cam?
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I forget how much you managed to raise your compression by when you shaved the heads... Was it 10.1 : 1 or 10.3 : 1 ?
So the KR is only happening under Load when the TCC is locked... With your compression and new cam could the TCC be locking at too low of a road speed being that you have brought up your compression and your bit more bumpy cam?
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Joined: Jun 2002
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I would not have believed it to be caused by your EGR system. I've had mine disconnected for a few years now and have no KR problems.
What is your timing curve like? Are you running a reprogrammed PCM? Have you scanned for other parameters?
What is your timing curve like? Are you running a reprogrammed PCM? Have you scanned for other parameters?
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Posts like a Corvette
Joined: Aug 2004
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From: South Bend, IN (hometown) Indianapolis,IN (college)
im having the same problem, minus the cam and heads stuff. ill be intrested to see whats causing yours.
did you consider than its your tranny? thats kinda what i think mine might be
did you consider than its your tranny? thats kinda what i think mine might be
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From: Purgatory
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