Runs badly after time - resetting ECU seems to help?
Posted: Sun Jul 08, 2018 12:57 pm
I have an M52 in my E30 and it seems to develop issues over time, but then runs okay if I leave the ECU unplugged overnight.
The symptoms develop to become jerking half the time (as if I'm messing around with the throttle), lumpy idle, and lack of power. It almost seems as if one cylinder intermittently turns off and on. I could be cruising at 40mph with the car jerking and bucking then instantly it'll just purr like a dream for a few minutes. Then it'll begin bucking and jerking again.
Unplugging the ECU overnight seems to solve it, until the symptoms develop again.
I was advised maybe the O2 sensors are plugged in the wrong way around, so it was reading emissions wrong and constantly trying to correct itself. But I've had a look and i'm sure they're plugged in correctly.
Tried two MAFs and tested the TPS - all seems fine.
I've had my codes read but I sent the ECU off to do so as my port doesn't work. This means that some of these faults are triggered when the ECU was plugged in, and are therefore unreliable. The O2 sensors for example have only been triggered once and it was the most recent switch-on, meaning they probably only triggered because the ECU was switched on without being plugged into a car. They came back as follows:
Code - Description - Times seen - Countdown
Any ideas?
The symptoms develop to become jerking half the time (as if I'm messing around with the throttle), lumpy idle, and lack of power. It almost seems as if one cylinder intermittently turns off and on. I could be cruising at 40mph with the car jerking and bucking then instantly it'll just purr like a dream for a few minutes. Then it'll begin bucking and jerking again.
Unplugging the ECU overnight seems to solve it, until the symptoms develop again.
I was advised maybe the O2 sensors are plugged in the wrong way around, so it was reading emissions wrong and constantly trying to correct itself. But I've had a look and i'm sure they're plugged in correctly.
Tried two MAFs and tested the TPS - all seems fine.
I've had my codes read but I sent the ECU off to do so as my port doesn't work. This means that some of these faults are triggered when the ECU was plugged in, and are therefore unreliable. The O2 sensors for example have only been triggered once and it was the most recent switch-on, meaning they probably only triggered because the ECU was switched on without being plugged into a car. They came back as follows:
Code - Description - Times seen - Countdown
Any ideas?