Car is a 1987 325e
Alright, so I have been trying to figure this out for a month now, and it is about time to get some other peoples opinions. The car runs fine as it warms up. Once the car is warm, while driving at a constant throttle or off idle during acceleration, the car will hesitate very badly. If you push the clutch in, rev it a couple times, then slip the clutch with high revs you will get a slight to big back fire. After a bit of that the car will end up just dying completely. It started out as a very slight hesitation, and for quite some time it was like that. So I didn't really worry about it. Then it just got so bad I couldn't drive it. Oh and the O2 sensor had been replaced about a month before this issue started. I don't think it has any relevance to the issue as it runs the same whether the O2 is plugged in or not.
Here is everything I've checked in order.
Fuel Filter and plugs- Had a ton of water in it, replaced. Plugs were super lean, hadn't been replaced in awhile so I went ahead and replaced them.
Drained Tank- Very little water in it. So went on to check the fuel pump. It was fine.
Checked rotor and distributor cap. Rotor was fine, distributor cap was pitted. I filled it down and put it back on. I didn't ohm it out at this time.
Ohmmed the reference sensor and speed sensor. Both were on the high side, around 1250 and 1300 so I went ahead and replaced them. Still didn't fix the problem.
I had another ECU for this car that was chipped, and I knew was okay. I swapped them and still had the problem.
Checked the plugs again. This time they were very rich. Was running great until it got up to running temp then the problem would start again.
Checked the coolant temp switch and sensor. Both were fine.
Checked all the intake sensors and looked for vacuum leaks. No issue's were found with any of the sensor or vacuum lines.
Ohmmed out the ignition coil, it was fine. Had doubts though whether it was breaking down once it warmed up. So I went ahead and replaced it.
That still didn't fix the problem.
Checked for a leak at the cam for the rotor/distributor. No leak, decided to go ahead and ohm out the rotor and cap for the hell of it. Rotor ohmmed out fine, cap didn't. Was consistently 10k to 30k ohms, a couple poles didn't even have continuity, so I went ahead and replace that cap.
That still didn't fix the issue but the car was running stronger will it was still cold.
Checked fuel pressure next. I put the gauge inline at the cold start injector. Fuel pressure was 129. I clamped down the line after the fuel regulator and the pressure came up to just under 150. I figured the regulator was bad so I went ahead and replaced it. Took it out again.
It ran great for a minute once it was warm, but I was flogging it. I then decided I needed to drive it like I would and traffic, and it started doing it all over again. I looked at the cold start injector to see if it was wet, or weeping, and it wasn't. Oh, and the plugs are wet across the board. They all look the same.
That is where I am now. Tomorrow I am going to check the fuel pressure again to see if it is still low. If it is, I guess I am going to check the injectors? I don't see how they could all be equally leaking unless the control unit was telling them to stay open longer for some reason. There are no leaks in the system to cause it to be low.
I'm really at a loss right now. I think I have been thinking about it to much and am trying to back up and look at things from the beginning. If anyone has any ideas, or think I need to double check something, ppplllleeeassssee tell me. Thanks.
Alright, so I have been trying to figure this out for a month now, and it is about time to get some other peoples opinions. The car runs fine as it warms up. Once the car is warm, while driving at a constant throttle or off idle during acceleration, the car will hesitate very badly. If you push the clutch in, rev it a couple times, then slip the clutch with high revs you will get a slight to big back fire. After a bit of that the car will end up just dying completely. It started out as a very slight hesitation, and for quite some time it was like that. So I didn't really worry about it. Then it just got so bad I couldn't drive it. Oh and the O2 sensor had been replaced about a month before this issue started. I don't think it has any relevance to the issue as it runs the same whether the O2 is plugged in or not.
Here is everything I've checked in order.
Fuel Filter and plugs- Had a ton of water in it, replaced. Plugs were super lean, hadn't been replaced in awhile so I went ahead and replaced them.
Drained Tank- Very little water in it. So went on to check the fuel pump. It was fine.
Checked rotor and distributor cap. Rotor was fine, distributor cap was pitted. I filled it down and put it back on. I didn't ohm it out at this time.
Ohmmed the reference sensor and speed sensor. Both were on the high side, around 1250 and 1300 so I went ahead and replaced them. Still didn't fix the problem.
I had another ECU for this car that was chipped, and I knew was okay. I swapped them and still had the problem.
Checked the plugs again. This time they were very rich. Was running great until it got up to running temp then the problem would start again.
Checked the coolant temp switch and sensor. Both were fine.
Checked all the intake sensors and looked for vacuum leaks. No issue's were found with any of the sensor or vacuum lines.
Ohmmed out the ignition coil, it was fine. Had doubts though whether it was breaking down once it warmed up. So I went ahead and replaced it.
That still didn't fix the problem.
Checked for a leak at the cam for the rotor/distributor. No leak, decided to go ahead and ohm out the rotor and cap for the hell of it. Rotor ohmmed out fine, cap didn't. Was consistently 10k to 30k ohms, a couple poles didn't even have continuity, so I went ahead and replace that cap.
That still didn't fix the issue but the car was running stronger will it was still cold.
Checked fuel pressure next. I put the gauge inline at the cold start injector. Fuel pressure was 129. I clamped down the line after the fuel regulator and the pressure came up to just under 150. I figured the regulator was bad so I went ahead and replaced it. Took it out again.
It ran great for a minute once it was warm, but I was flogging it. I then decided I needed to drive it like I would and traffic, and it started doing it all over again. I looked at the cold start injector to see if it was wet, or weeping, and it wasn't. Oh, and the plugs are wet across the board. They all look the same.
That is where I am now. Tomorrow I am going to check the fuel pressure again to see if it is still low. If it is, I guess I am going to check the injectors? I don't see how they could all be equally leaking unless the control unit was telling them to stay open longer for some reason. There are no leaks in the system to cause it to be low.
I'm really at a loss right now. I think I have been thinking about it to much and am trying to back up and look at things from the beginning. If anyone has any ideas, or think I need to double check something, ppplllleeeassssee tell me. Thanks.
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