89mulletbird
Member
- Joined
- Jun 24, 2004
- Messages
- 363
I had a powerlogger trace, but can't find it right now.
Anyways, I have replaced about every electrical component on the car, but once I'm cruising over 3k RPMs, I start losing RPM counts, and the car starts backfiring while the tach goes erratically between 3k and 0 RPM. Datalogger shows the RPM toggling between 3000 and 1500 so it looks like somehow I am missing some of the pulses from the crank sensor.
If I shift it into OD and drop the RPMS below 3,000, the problem goes away instantly, then when I shift back into 3rd and the RPMs are above 3,000 it starts losing tach counts and backfiring again.
I replaced crank sensor, ECM, and ignition module but the problem persists. I cleaned the contacts on the crank sensor and ignition module also.
What else could cause the ECM/ignition module to calculate the wrong RPM?
Anyways, I have replaced about every electrical component on the car, but once I'm cruising over 3k RPMs, I start losing RPM counts, and the car starts backfiring while the tach goes erratically between 3k and 0 RPM. Datalogger shows the RPM toggling between 3000 and 1500 so it looks like somehow I am missing some of the pulses from the crank sensor.
If I shift it into OD and drop the RPMS below 3,000, the problem goes away instantly, then when I shift back into 3rd and the RPMs are above 3,000 it starts losing tach counts and backfiring again.
I replaced crank sensor, ECM, and ignition module but the problem persists. I cleaned the contacts on the crank sensor and ignition module also.
What else could cause the ECM/ignition module to calculate the wrong RPM?