‘89 325is engine starts but intermittently stalls only within first 5 miles

[Frey]

Hello, I have an ‘89 325is with 170k miles that will start and idle when cold but will stall anywhere from 1- 4 times within the first 5 miles before running normal beyond 5 miles. The car does not sputter and die like it’s starving for fuel, it just quits. The car can be going anywhere from 10 - 60 mph when it stalls and I can typically push the clutch pedal and restart quickly while the car is moving at highway speeds. One time it started itself ~2 seconds after it quit at highway speed when I wasn’t able to depress the clutch in time. However there are other times when the car needs to be pulled over to the side of the road and the engine needs to be cranked over 10-15 seconds before it will restart. Once the car is driven roughly 5 or so miles it then runs flawlessly until the next time the engine is cold again.

I have replaced both the main and fuel relays, wiggled the key in the ignition switch when the car stalls while still moving but this made no difference. Also checked the coil wire connection to make sure that was secure.

Any suggesting what to check next would be much appreciated.

Thank you, Jeff

[ADEN]

I would vote for bad CPS try cleaning it and check if it is not loose or not centered to face the crank pulley.

Good luck..

[laidback93]

I would vote for bad CPS try cleaning it and check if it is not loose or not centered to face the crank pulley.

Good luck..

Ditto. Check the CPS first.

Second, would be to check your charging system. Alternator, bad ground strap, etc.

What you described is almost identical to what I experienced when my alternator was going out.

[Frey]

Thank you for the input guys! I’ll look into the CPS and report back.

[Gregs///M]

If CPS does not repair it, consider a failing AFM.

[zwill23]

Check your fuel pump connections to be safe, I had a bad fuel pump connection inside the tank cause a similar intermittent issue.

[Frey]

Thanks for the additional suggestions. I just received the cps, will install it this week and report back.

[Frey]

I replaced crank shaft position sensor, along with the cap and rotor and checked the alternator ground strap as suggested above but still having the same problem of the car just instantly quitting like you’ve turned off the ignition key. Very odd as this only occurs ~50% of the time, only when vehicle is cold, and only within the first 5-7 minutes of operation. Once past that first 5-7 minute mark the car runs flawlessly.

[Gregs///M]

Definitely sounds like a failing AFM. It will cause the car to stall, intermittent misfire type symptoms, loss of power and poor idle are among some of the failure modes.

[Frey]

Still having problems with the engine quitting issue although some updates and changes I’ve noticed. I did change out the coolant thermostat sensor as it looked original. The first 5-6 times I had the vehicle out this spring it ran flawlessly. The last few times it has started quitting again and last week was the first time it quit on me after 10 minutes of operation. I had driven the car 30 miles when it quit. I’m hoping whatever is failing is finally getting worse and may fail completely. At this point I’ve replaced the main fuses, cps, coolant thermostat and checked for any vacuum leaks. I have not looked into the AFM. Would a bad afm cause the engine to just quit instantly driving a steady 60 mph down the highway at full operating temperature?

Thanks in advance for any input on this. Jeff

[Old525i]

Fuel Pressure Regulator?

[e30davie]

If it runs perfect for a while, then doesn't, id be questioning the fuel pump. I had a fuel pump years ago in an old toyota that would work fine for about 30mins then i assume would overheat or something then would stop supplying. give it a bit of a break and it would be ok and then repeat the failure. You can confirm this if you can get a fuel pressure gauge inline with your fuel line. then when it starts playing up jump out of the car and see what its like. A cheap fuel pressure gauge and a few barbed fittings shoudlnt cost you much, and just temporarily install it. it would be a good thing to have on the shelf to use another time.

I put a fuel pressure gauge on the toyota i mention above and when the pump started to fail the pressure would be quite sporadic and eventually drop.

Fuel pump doesn't completely explain your symptoms, but If you don't know the history of the fuel pump might be worth swapping it out anyway