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KR at 1400-2500 rpm

9

97gpl36

New member
I'm still having 12-16 degrees of KR when leaving a stop at slow rates of speed (granny takeoff),but when accelerating quicker the rpm move through the KR zone (1400-2500) sometimes only causing up to 3*KR.
While travel at 78 mph,KR will occasionally pull 12-16 of timing.
The weird thing is when trying to duplicate the problem area at low speeds,I can't always get the KR,this intermittent issue makes me wonder if the pcm is
causing false knock.PCM was re-flashed at dealer a couple of months ago,but the KR is gradually pulling more timing at lower rpm in previous weeks.
Knock sensors have been replaced,and I've ran three different knock modules in the PCM that made no difference.Car runs healthy at WOT without KR.
'97' GP GT is n/a with 513 lift Comp cam,105 lb springs,ported heads and LIM.
Anyone else know of a solution to this problem?
Having to run stock tune at moment until funds become available.
 


False knock is what I've been thinking too,since the engine is fresh and 93
octane make no difference.Today I supported the GP on stands and selected overdrive,slowly increased rpm to the KR zone (1800-2500 rpm), and WTF?,
A sound like a slant 6 spinning rod bearings in my engine bay.
When feathering throttle in dreaded zone there is audible knock that can't be heard while driving,almost a bottom end noise,but seems to be coming from trans on TC side,park and neutral produce no weird sounds through rpm range.Something kind of chunky sound down there,car shifts really nice when KR isn't present,but most of the time at given rpm it is pulling serious timing.
I don't recall what brand of timing components I am running,but my machinist assured me that it would be durable with my 105 LB. valve springs.
Do these torque converters crap out when you punish the hell out of them?
It is stock to my knowledge.
 
97gpl36 said:
I'm still having 12-16 degrees of KR when leaving a stop at slow rates of speed (granny takeoff),but when accelerating quicker the rpm move through the KR zone (1400-2500) sometimes only causing up to 3*KR.
While travel at 78 mph,KR will occasionally pull 12-16 of timing.
The weird thing is when trying to duplicate the problem area at low speeds,I can't always get the KR,this intermittent issue makes me wonder if the pcm is
causing false knock.PCM was re-flashed at dealer a couple of months ago,but the KR is gradually pulling more timing at lower rpm in previous weeks.
Knock sensors have been replaced,and I've ran three different knock modules in the PCM that made no difference.Car runs healthy at WOT without KR.
'97' GP GT is n/a with 513 lift Comp cam,105 lb springs,ported heads and LIM.
Anyone else know of a solution to this problem?
Having to run stock tune at moment until funds become available.
Click to expand...

ClubGP Message Forum troubleshooting
 
Really common problem with 97s...

I raise knock RPM detection enable to a few hundred rpms above where you have that issue. Works every time, and the fix only limits your ablity to have the pcm automatically switch timing tables at cruise.
 
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