Engine Dies While Cruising

[Drewe30e]

I've searched the forum and haven't come up with anything concrete.

A couple days ago, my 325e randomly shut off while driving. I wasn't giving it extra throttle or letting off...just cruising at about 40 mph. When this happens the tach reads zero and the power steering dies. When I pull off and restart it, it takes a few seconds this starts right up. I've had this problem a few more times since and don't really want to get on the interstate and have it die.

Right now I'm almost due for an tune-up. I can't imagine that would be the problem though. The only idea I have is to replace the ECU. Thoughts?

[nando]

how about the fuel pump or main relays?

[Turf1600]

fuel pump failure?

[Turf1600]

damn beat me to it

[Drewe30e]

I've never changed the fuel pump and don't know if it ever has been. The fuel pump relays are in the black box in front of the driver side strut tower, right? Which one is it in there. I wish I had my Bentley with me, but I'm out of town right now. Thanks for all of the help.

[delphini]

First hand experience , when my 153 ecu went nothing worked it just went kaput! I'm currently experiencing the same symptoms with my car , next week and we'll see if a new pump will fix . Already replaced the relay.

[delfin]

vacuum tube or airbox?

[James Crivellone]

Main Relay is failing.. This explains why the tachometer is showing zero as well... the ECU is turning off.

[AndrewBird]

Main Relay is failing.. This explains why the tachometer is showing zero as well... the ECU is turning off.

It could be showing zero because the engine dies. Although with the clutch out in gear, would it still show RPM's even if the engine wasn't running? Maybe he can clarify what he meant by reading zero.

[92 mtechnic cabrio]

couldn't it also be the crank position sensor? I have this problem every once in a while as well.

I'll be cruising, throttle position doesn't matter, then all of the sudden the engine will die. If it's in gear then it will stay running (and my power steering will remain running). If I happen to have clutched in when it dies, then yeah it dies, but I just let the clutch out in the next gear and it fires back up.

I tried switching the main relay with a known working one and the symptoms didn't go away.

Thats why I'm starting to believe it's the crank position sensor.

[Drewe30e]

As for reading zero, that is while the clutch is still in. I tried to release the clutch to start the car again but it didn't work.

I replaced the CPS one time with a used one because my car stopped starting one day. I guess there's a possibility that it is bad. There's still a possibility lots of things are bad. :/

[James Crivellone]

It could be showing zero because the engine dies. Although with the clutch out in gear, would it still show RPM's even if the engine wasn't running? Maybe he can clarify what he meant by reading zero.

If the ECU is still receiving power, and the engine is rotating, then yes the tachometer will still read properly.

[Drewe30e]

I guess I'll try replacing the main relay. Any other suggestions?

[94530inh]

sticking AFM?

[redhatpat]

sticking AFM?

No, doesn't match symptoms.