Random m20 engine glitch

[excellone]

I have an ’88 325i automatic with a random engine issue when warm and moving. The check engine light comes on and engine will act like its trying to shut off. Sometimes it would not glitch for several days. However, today with warm/humid weather, the engine shut off. A mechanic looked at it and had it cut out at 6200 rpm consistently. I used a Bentley manual and had replaced these components that were not to spec.

MAF meter
O2 sensor
Crank sensor
Ignition wires
Coil
Plugs (using Bosch copper)
Cap
Rotor
Throttle position sensor
C191 connector
Main relay
Fuel pump relay (original was warm and has carbon tracts on blades )
Swapped ECUs
Vacuum is good

Diagnostic code indicates a break in FP relay. I will diagnose the fuel pump relay board to see if there is a voltage/loss when energized.

Has anyone experienced such an issue?


Thanks

George

[Numark318i]

Originally Posted by excellone

I have an ’88 325i automatic with a random engine issue when warm and moving. The check engine light comes on and engine will act like its trying to shut off. Sometimes it would not glitch for several days. However, today with warm/humid weather, the engine shut off. A mechanic looked at it and had it cut out at 6200 rpm consistently. I used a Bentley manual and had replaced these components that were not to spec.

MAF meter
O2 sensor
Crank sensor
Ignition wires
Coil
Plugs (using Bosch copper)
Cap
Rotor
Throttle position sensor
C191 connector
Main relay
Fuel pump relay (original was warm and has carbon tracts on blades )
Swapped ECUs
Vacuum is good

Diagnostic code indicates a break in FP relay. I will diagnose the fuel pump relay board to see if there is a voltage/loss when energized.

Has anyone experienced such an issue?


Thanks

George

i did with my 318. Turns out the fuel pump was not working properly.

[nick_318is]

My guess is its the fuel pump or the relay for it I have heard of this problem with the m20, some people swear to keep an extra relay with them.

[excellone]

Today I cleaned the relay sockets/connectors and reset the DME. There was no voltage drop across the FP relay.

No glitches after a 40 minute ride. A failing fuel pump maybe the main issue. It has 159k and original fuel pumps, regulator, lines and injectors. It runs very well when not glitching.

Thanks for the replies,

George

[excellone]

Update:

I looked over the vacuum line from charcoal can to purge valve after smelling gas vapors. I discovered it loose on the valve with cracked ends. A wire tie around this end seemed to fix the stumble/check engine light after 2 hours of driving. Hope this random thing goes away.

George