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Hi Spec E30 folks…
…from a PRO-3 guy in the NW. I have been working to solve a cut at around 5200 to 5300 rpms in my car now for 2 years.
Any of you guys had these issues? If so what fixed it?
We have changed everything in the car now and can’t figure this out.
Helpless in Seattle.
At this point any ideas are good ideas.
Fred Wright
#68 PRO-3
How big of a cut?
My car whent flat at those speeds and after some dyno work we traced it the ECU. Other cars have had worn out MAF create flat spots.
Don
Patton had a loose vibration damper cause something similar. Flat spots can be caused by a bad TPS.
Does it feel like a fuel cut? Ignition cut? What have you replaced/done? When did the problem start?
The cut is one second and it drops the tach - then comes right back. When it comes back the engine seems flat from 5000-6400 for the rest of the session. The cut happen at full throttle under load but is sporadic. It seems to happen more as the engine warms up. At the exit of most important corner (nice huh?!)
We have replaced the ecu (4+), the MAF(4+), the wiring harness (2X), all the wiring (Painless wiring harness), doubled the grounds, change kill switches, heads, bottom ends, ignition sets(2x), plug wires, fuel rails, injectors (2x), fuel pumps, batteries, coils, all sensors and turned off all gauges.
We thought we fixed it with a crank position sensor but it came back.
We are going to try a new intake, wiring harness and ecu from a working car.
The symptoms sound more than a bit familiar…
Based on my experience in trying to solve what sounds to be exactly the same problem, I’d suggest looking at the harmonic balancer and wiring harness. The full story of hunting down a similar problem can be seen at:
http://spece30.com/component/option,com_kunena/Itemid,86/func,view/id,17824/catid,5/
are you using a chip? If so have you been swapping the same chip between ecu’s? Just a thought!
