I have a 1990 325i Convertible with an M20 and automatic transmission. When I got the car it was in pretty rough shape, but the engine ran fine despite having old gas in the tank. The odo read 64k but had stopped working. After driving it to a place I could work on it (~50 miles in total) it was still running alright.
I then installed the following parts:
New Bosch 3 19lbs Injectors
New Bosch Copper Spark Plugs
New Timing Belt
New Tensioner
New Water Pump
New Power Steering Belt
New Alternator Belt
New AC Belt
New Valve Cover Gasket
New Thermostat
New Fuel Filter
After all of this had been done I fired it up and it started, but the tensioner slipped and I cut it immediately. I heard it clank about 3 times though. To be sure that I didn't mess up any valves I preformed a compression test. I had to get a crappy one form a parts store and the readings were all low, ~120psi, but consistent. (I later went back with a good one and got compression of about 135 +/- 3 on all cylinders.) I corrected the timing belt, double checked the tensioner, double checked the alignment and felt safe to start it again. It started with out trouble and no unusual sounds.
At this point I encountered an idle issue and a bit of a hesitation. I adjusted the valve timing, twice, and the hesitation cleared up. It was having problems stating when warm but I wasn't too concerned with that so I took it to get emissions done (Location: GA). I got there and told them not to turn it off because I wan't sure it would start again. It passed with flying colors (probably due to the holes in the exhaust). I then drove it around for a bit enjoying the weather. It pulled fine, transmission wasn't the smoothest but I drive a manual so I cant really compare it to anything. Got home after about 20 miles of driving and parked it.
I took a look at the vacuum lines and found one was cracking so I replaced it and the problem persisted. I checked the vacuum lines for leaks and found none. I sprayed starter fluid over every inch of the dang thing and got no change in the idle. Tested the ICV and it was good. I took the intake boot off and out poured a good bit of fuel (Maybe 1/8 of a cup? Not too good at estimating that kind of thing). There was fuel all through the intake system so I let it air out and it stated just fine. I let it idle for a bit and checked the intake again and found more fuel. I waited a day and started it, then turned it off before it could warm up. Found fuel in the intake manifold once again and it would not start. The exhaust was cold the the touch so I assume the starting problem is not heat related.
Since then the idle and misfire have been getting progressively worse and still would not start after it ran for a couple minutes. Eventually it stopped running smoothly and began to misfire. At first it was only when it was below 3000rpm that it was rough, but now it misfires so bad that it almost dies at idle. Mashing the gas yields almost no results. It cannot build up the RPMs.
I tested the following and found them to be good:
Spark at all plugs and wires
Coil has good resistance
ECU is good
Compression is good (135 +/-3)
Voltage Supply to Control units good
Wire from starter to solenoid good
Coolant temp sensor good
Throttle Switch good
Air Flow sensor good
Oxygen sensor good
Main grounds good
Checked the continuity to pin 85 at the main relay and got nothing. Went through and checked all the pins in that relay plug and got nothing.
That about sums it up. Misfires are still there, but can't really speak to the idle. A bit long winded but didn't want to leave anything out. Any help or ideas at all?
Note: I also have a 1989 325i with an M20 and a manual transmission the runs fine. I can swap parts to check if they are good if needed.
I then installed the following parts:
New Bosch 3 19lbs Injectors
New Bosch Copper Spark Plugs
New Timing Belt
New Tensioner
New Water Pump
New Power Steering Belt
New Alternator Belt
New AC Belt
New Valve Cover Gasket
New Thermostat
New Fuel Filter
After all of this had been done I fired it up and it started, but the tensioner slipped and I cut it immediately. I heard it clank about 3 times though. To be sure that I didn't mess up any valves I preformed a compression test. I had to get a crappy one form a parts store and the readings were all low, ~120psi, but consistent. (I later went back with a good one and got compression of about 135 +/- 3 on all cylinders.) I corrected the timing belt, double checked the tensioner, double checked the alignment and felt safe to start it again. It started with out trouble and no unusual sounds.
At this point I encountered an idle issue and a bit of a hesitation. I adjusted the valve timing, twice, and the hesitation cleared up. It was having problems stating when warm but I wasn't too concerned with that so I took it to get emissions done (Location: GA). I got there and told them not to turn it off because I wan't sure it would start again. It passed with flying colors (probably due to the holes in the exhaust). I then drove it around for a bit enjoying the weather. It pulled fine, transmission wasn't the smoothest but I drive a manual so I cant really compare it to anything. Got home after about 20 miles of driving and parked it.
I took a look at the vacuum lines and found one was cracking so I replaced it and the problem persisted. I checked the vacuum lines for leaks and found none. I sprayed starter fluid over every inch of the dang thing and got no change in the idle. Tested the ICV and it was good. I took the intake boot off and out poured a good bit of fuel (Maybe 1/8 of a cup? Not too good at estimating that kind of thing). There was fuel all through the intake system so I let it air out and it stated just fine. I let it idle for a bit and checked the intake again and found more fuel. I waited a day and started it, then turned it off before it could warm up. Found fuel in the intake manifold once again and it would not start. The exhaust was cold the the touch so I assume the starting problem is not heat related.
Since then the idle and misfire have been getting progressively worse and still would not start after it ran for a couple minutes. Eventually it stopped running smoothly and began to misfire. At first it was only when it was below 3000rpm that it was rough, but now it misfires so bad that it almost dies at idle. Mashing the gas yields almost no results. It cannot build up the RPMs.
I tested the following and found them to be good:
Spark at all plugs and wires
Coil has good resistance
ECU is good
Compression is good (135 +/-3)
Voltage Supply to Control units good
Wire from starter to solenoid good
Coolant temp sensor good
Throttle Switch good
Air Flow sensor good
Oxygen sensor good
Main grounds good
Checked the continuity to pin 85 at the main relay and got nothing. Went through and checked all the pins in that relay plug and got nothing.
That about sums it up. Misfires are still there, but can't really speak to the idle. A bit long winded but didn't want to leave anything out. Any help or ideas at all?
Note: I also have a 1989 325i with an M20 and a manual transmission the runs fine. I can swap parts to check if they are good if needed.
Comment