Hi there I have a 1984 bmw 325e and I am having a particular issue that has led me to spend too much and stress too hard over this car without driving it. Every time I start the car it starts and then immediately goes to very low RPMs to where it's just above stalling and it can stay there until it warms up which is odd(see attached youtube clip). I have tried to replace many things and test many things; the P.O. did an awful job keeping up with the maintenance (replacing sensors and using OEM parts) and I have undone most of it so far. However, after doing everything listed below the thing still does the same thing. My next guess is to test the ECU plug to make sure everything is getting the connection there, and test the ICV valve resistance and make sure it's getting to the ECU. I also saw one post that talked about the Intake nut backing off causing a vacuum leak I have sprayed the engine with carb cleaner and smoke tested the engine and have not found anything but I will try to spray further down in the engine bay and see. I know there is a mention of the valve cover bolt needing to be tapped- I have sprayed that with carb cleaner to see if that revs it up but it didn't. I am coming very close to selling the motor and swapping the 350 SBC me and my dad have in our backyard into it and putting in a standalone ECU. I would love to save this motor with how much work and money I've put in and I could use the help! Thank you to all those that help out!
Misc.
Vacuum leaks – Fixed Crankcase Leak, Intake Boot Leak, AFM leak, and Cold Start Injector leak
Head gasket and other gaskets – New
Brake Master Cylinder – new from P.O
Timing Belt – New from P.O verified proper timing when reinstallation of head
Made sure the Throttle Body Set Screw is set right
Electronics
02 sensor – new
TPS – New and working correctly
AFM – Rebuilt and working correctly
Coolant Temp Sensor – New and working correctly
Thermo Time Switch – New and working correctly
Coolant Dash Sensor – New / fixed wiring
ICV – is old but fixed wiring and seems to be working will have to test it still
ECU – taken apart and looks okay will have to test connections and swap with another
DME – Swapped with another, no change
Alternator – New
Fuel
In-line Fuel pump – new
Fuel Filter – New (1/2)
Fuel Injectors – Rebuilt
Fuel Rail – New
Fuel Pressure Regulator – New
Ignition
Spark plugs – new but have been dumped with gas
Cap and Rotor – not replaced but have new replacements
Spark Plug Wires – not replaced
Main Coil – Working and wired correctly
Known Issue
The valve Cover has a stripped bolt in the rear passenger side by the ground strap will need to tap
Valves don’t know when they have been adjusted last.
Wiring to Gauge Cluster has issues – Battery Light doesn’t go on always have to mess with wiring, RPM gauge doesn’t always work (75% doesn’t 25% does)
Washer Fluid Reservoir Level Sensor needs replacement and reinstall reservoir
Check the Brake always on
While Diagnosing the issue found a coolant leak at the water pump to the thermostat hose (will replace it if I can figure out the idle issue)
Misc.
Vacuum leaks – Fixed Crankcase Leak, Intake Boot Leak, AFM leak, and Cold Start Injector leak
Head gasket and other gaskets – New
Brake Master Cylinder – new from P.O
Timing Belt – New from P.O verified proper timing when reinstallation of head
Made sure the Throttle Body Set Screw is set right
Electronics
02 sensor – new
TPS – New and working correctly
AFM – Rebuilt and working correctly
Coolant Temp Sensor – New and working correctly
Thermo Time Switch – New and working correctly
Coolant Dash Sensor – New / fixed wiring
ICV – is old but fixed wiring and seems to be working will have to test it still
ECU – taken apart and looks okay will have to test connections and swap with another
DME – Swapped with another, no change
Alternator – New
Fuel
In-line Fuel pump – new
Fuel Filter – New (1/2)
Fuel Injectors – Rebuilt
Fuel Rail – New
Fuel Pressure Regulator – New
Ignition
Spark plugs – new but have been dumped with gas
Cap and Rotor – not replaced but have new replacements
Spark Plug Wires – not replaced
Main Coil – Working and wired correctly
Known Issue
The valve Cover has a stripped bolt in the rear passenger side by the ground strap will need to tap
Valves don’t know when they have been adjusted last.
Wiring to Gauge Cluster has issues – Battery Light doesn’t go on always have to mess with wiring, RPM gauge doesn’t always work (75% doesn’t 25% does)
Washer Fluid Reservoir Level Sensor needs replacement and reinstall reservoir
Check the Brake always on
While Diagnosing the issue found a coolant leak at the water pump to the thermostat hose (will replace it if I can figure out the idle issue)
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