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Hey guys I'm hoping you can help me solve an issue I have with initial throttle input at very low RPM. I will just get off the clutch and very gradually step on the throttle and I get my car jerking back and fourth where I can hear the diff slapping.
I attached my map and a data log. If you view only RPM and vehicle speed, you'll see there are 2 instances where RPM peaks and goes to the top of the graph.,As the RPM rises it oscillates considerably, and this is what you feel in the car just at light initial throttle input.
Please let me know what you think I can do to try and smooth this out, all thoughts are appreciated!!
Car is a 1990 bmw 325i with twin turbos running 11psi of boost
Bump.. any thoughts?
The only thing I can see in the logs that is jumping around with RPM is the ignition advance, but wether that is a result of the rpm jumping around or causing it im not sure... maybe lock the ignition to 20-25 degree's or just set all the cells in that area to 25 degree's and see if the problem persists or goes away...
Hi- Just a thought but how is the idle speed maintained ? By timing ? If you are pulling the engine down into a low enough point that the ecu cranks up the timing at that point it might give you the symptoms you are describing .