M50TU dieing, causes?

[bubba966]

Working on a friends '95 525iT that's got about 173K on it.

It's currently stuttering and dieing. CEL flashes while it stutters, then it dies with most of the lights going on in the cluster as well as saying trans program and a few other things.

Volts at idle is 14.25, volts with engine off is 12.43. Battery is 4 years old (something from batteries plus that was installed by dealer they bought it from)

Haven't stomp tested it yet, will do it tomorrow.


This started yesterday after I spent all day replacing the crank sensor and swapping out the passengers side low beam. Crank sensor was a brand new BMW unit from Tischer, low beam used from Garret (though I don't see the low beam install contributing to this at all).

I'd put it all back together last night when it was dark out. As such I'd not noticed that one of the injectors wasn't fully seated and was spraying fuel all over the place on initial start up. Shut it off, reseated the injectors & fuel rail to fix the fuel leak. Then poured about 2 gallons of water over the intake manifold to rinse off the excess gas so it didn't catch fire and look like Brody's pics of his E34 BBQ.

Car ran beautifully after I reseated the fuel rail. Never ran so well that I recall.

But maybe 15 minutes after the CPS install it died. Let it sit for a few minutes while I had the DME disconnected then it started up again. Died another few minutes down the road. Once again unplugged the DME for a reset and waited a bit. Started again and ran for a few more minutes. Seems to run for a few minutes before it dies.

Am almost thinking that steam from the engine drying itself after the rinse has gotten into some connection in the engine bay and is causing it to die.

Tomorrow will take things apart and WD-40 the water out of things. Will also try putting the old CPS back in the car. Will have to measure the new and old CPS's while I'm at it.

Anyone have any other ideas? It's dieing like it's a battery issue, but voltage seems fine, and wasn't showing any signs of low voltage before the CPS install and was cranking over fine.
Edit/Delete Message

[bubba966]

No one's got any guesses?

[BennyM]

I'd start with the stomp test to see what that CEL is trying to tell you. When it does run, what's the idle like? Does it stutter or fluctuate at all?
Also, check for vacuum leaks by pulling out the oil dipstick to see if idle gets rougher. Did you replace the o-rings on the injectors when you replaced the fuel rail?

This forum has seen a lot of cases where steam cleaning the engine bay caused a vast array of electrical issues until it all dried out. So, what you described sounds plausible.

Working on a friends '95 525iT that's got about 173K on it.

It's currently stuttering and dieing. CEL flashes while it stutters, then it dies with most of the lights going on in the cluster as well as saying trans program and a few other things.

Volts at idle is 14.25, volts with engine off is 12.43. Battery is 4 years old (something from batteries plus that was installed by dealer they bought it from)

Haven't stomp tested it yet, will do it tomorrow.


This started yesterday after I spent all day replacing the crank sensor and swapping out the passengers side low beam. Crank sensor was a brand new BMW unit from Tischer, low beam used from Garret (though I don't see the low beam install contributing to this at all).

I'd put it all back together last night when it was dark out. As such I'd not noticed that one of the injectors wasn't fully seated and was spraying fuel all over the place on initial start up. Shut it off, reseated the injectors & fuel rail to fix the fuel leak. Then poured about 2 gallons of water over the intake manifold to rinse off the excess gas so it didn't catch fire and look like Brody's pics of his E34 BBQ.

Car ran beautifully after I reseated the fuel rail. Never ran so well that I recall.

But maybe 15 minutes after the CPS install it died. Let it sit for a few minutes while I had the DME disconnected then it started up again. Died another few minutes down the road. Once again unplugged the DME for a reset and waited a bit. Started again and ran for a few more minutes. Seems to run for a few minutes before it dies.

Am almost thinking that steam from the engine drying itself after the rinse has gotten into some connection in the engine bay and is causing it to die.

Tomorrow will take things apart and WD-40 the water out of things. Will also try putting the old CPS back in the car. Will have to measure the new and old CPS's while I'm at it.

Anyone have any other ideas? It's dieing like it's a battery issue, but voltage seems fine, and wasn't showing any signs of low voltage before the CPS install and was cranking over fine.
Edit/Delete Message

[ahlem]

How deep is the water around each spark plug? A friend of my son's pressure washed his motor and filled them up nicely. Same symptoms as you describe.
Compressed air dried them out and all was well.

[genphreak]

How deep is the water around each spark plug? A friend of my son's pressure washed his motor and filled them up nicely. Same symptoms as you describe.
Compressed air dried them out and all was well.

On the M50 they are all covered up. I'd suspect that you could have fueling problems. How did it run after the hose-down? Perhaps check the ECU is getting signal from the CPS when it cranks.

Did u drive it afterwards?

[ryan roopnarine]

On the M50 they are all covered up. I'd suspect that you could have fueling problems. How did it run after the hose-down? Perhaps check the ECU is getting signal from the CPS when it cranks.

Did u drive it afterwards?

Here in florida, i find that i have to drain my plug wells out with qtips once every 6 months or so, a function of the amount I drive, and the amount of rain here.

[ryan roopnarine]

You're gonna want to do that stomp test before you worry yourself anymore. IIRC, the o2 sensor connector, the CPS and CamPS, ICV, and oil pressure as well as both water temperature sensors hide under the manifold. Which injector was spraying? Might you have drenched the cps that was on there?

Working on a friends '95 525iT that's got about 173K on it.

It's currently stuttering and dieing. CEL flashes while it stutters, then it dies with most of the lights going on in the cluster as well as saying trans program and a few other things.

Volts at idle is 14.25, volts with engine off is 12.43. Battery is 4 years old (something from batteries plus that was installed by dealer they bought it from)

Haven't stomp tested it yet, will do it tomorrow.


This started yesterday after I spent all day replacing the crank sensor and swapping out the passengers side low beam. Crank sensor was a brand new BMW unit from Tischer, low beam used from Garret (though I don't see the low beam install contributing to this at all).

I'd put it all back together last night when it was dark out. As such I'd not noticed that one of the injectors wasn't fully seated and was spraying fuel all over the place on initial start up. Shut it off, reseated the injectors & fuel rail to fix the fuel leak. Then poured about 2 gallons of water over the intake manifold to rinse off the excess gas so it didn't catch fire and look like Brody's pics of his E34 BBQ.

Car ran beautifully after I reseated the fuel rail. Never ran so well that I recall.

But maybe 15 minutes after the CPS install it died. Let it sit for a few minutes while I had the DME disconnected then it started up again. Died another few minutes down the road. Once again unplugged the DME for a reset and waited a bit. Started again and ran for a few more minutes. Seems to run for a few minutes before it dies.

Am almost thinking that steam from the engine drying itself after the rinse has gotten into some connection in the engine bay and is causing it to die.

Tomorrow will take things apart and WD-40 the water out of things. Will also try putting the old CPS back in the car. Will have to measure the new and old CPS's while I'm at it.

Anyone have any other ideas? It's dieing like it's a battery issue, but voltage seems fine, and wasn't showing any signs of low voltage before the CPS install and was cranking over fine.
Edit/Delete Message

[bubba966]

Took the coils out and two of them had damp boots. Blew them out with compressed air then took a hair drier to all of them to dry up any residual moisture. Didn't see any puddles in the plug wells, just the damp boots.

Started it up and it ran for about 18 minutes then died. Started it up again and it ran for 2-3 minutes then died. Wouldn't start up again after the second time it died. Didn't have time tonight to try a DME reset and restart.

But it's not much different than before. Last time it ran 15-18 minutes or so before it died the first time. Then it ran for 2 minutes or so before it died the second time.

It was the injector closest to the firewall that was spraying fuel all over the place. And I could've easily gotten the CPS connector and all of the other connectors in that area wet when I rinsed off the fuel with a 2 gallon pot of water.

Really weird that it starts up and runs fine for a bit then stutters and dies. Guess I'll have to pull the manifold off again and unplug everything and dry out the connectors. Not what I really want to do.

Currently my friend is driving my M-Sport until we get her touring running right again. She's kinda fond of my M-Sport and doesn't seem to mind having to drive it over her 525iT. Wonder why?... lol

[Grantus]

Those symptoms can mean that the fuel tank vent is blocked. I dont know what arrangement they have but it may be worth checking.

[bubba966]

Was thinking more about it on the way home from work just now.

What does anyone think about the possibility of the fuel pump is bad? Was thinking that it runs long enough to get something in the pump assembly warm enough to expand & bind causing the pump to either seize or seize enough that it stops supplying enough fuel and it stutters & dies.

That'd explain why it'll run for 15-18 minutes then die. Then will re-start immediately and run for a 2 or 3 minutes then die. Then it won't re-start after the second death. It'll crank and crank. And the more I think about it it's acting like it gets a tiny little bit of fuel (it's cranking like it's occasionally firing on a cylinder or two) but not enough to start.

I'm having a hard time figuring out any reason why it'd be a water in an electrical connection issue as when it starts up cold and runs great for the same 15-18 minutes or so, dies, runs fine for a few more minutes then dies, then won't start.

Or is this a possible thing that's fixed by that return line/check valve repair kit that's installed on top of the pump? It'd be awesome if that repair kit would fix this as I already got that kit and all associated gaskets to pull the pump & sender out.

Those symptoms can mean that the fuel tank vent is blocked. I dont know what arrangement they have but it may be worth checking.

Thanks, will have to look into that as well.