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Discussion Starter #1 (Edited)
My m5 sat for about 2 weeks as I was away. There were significant storms while I was gone, so there was a lot of moisture around the car.

I started it up and had no issues beyond a slightly hunting idle (seems to be a regular occurance now), but the car hesitated bigtime, ultimately stalling. I limped it back into the driveway where it stalled each time I tried to start it. I had some pending engine too rich and misfire codes, which I cleared.

I pulled and cleaned the MAFs (pretty dirty), and replaced the plugs (definitely needed it). The car starts, idles roughly for 1-2 seconds, then stalls. I can keep it running roughly if I ease on the gas, but it stalls right after I let up.

My first thought was one of the CPS. Car is under extended warranty, so it will be going in to the dealer tomorrow, but I'm curious if anyone has any other ideas. I'm guessing it isn't the fuel pump/relays as it will continue running if I give it gas. I unplugged the MAFs and it seemed to run a bit longer, but still stalled.

Also of interest was my last trip to the dealer, as the car started slightly overheating. I assumed thermostat, but they supposedly replaced the fan clutch, and told me one of my cats is clogged. The temp gauge went to 2/3 3 miles down the road after picking it up. I took it back and they told me it was because of the clogged cat, and that they would replace it for $2800. I laughed my way home, and have some high-flow aftermarket units on the way. I hadn't driven the car since then. Could it all be related? On a side note, is the big nut on the crank fan an integral part of the fan clutch? Mine is quite rusty, which is curious if it's all one unit and mine was just replaced.

Any insight would be appreciated, as I'm not sure I trust what the dealer is telling me.

Chris
 

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My m5 sat for about 2 weeks as I was away. There were significant storms while I was gone, so there was a lot of moisture around the car.

I started it up and had no issues beyond a slightly hunting idle (seems to be a regular occurance now), but the car hesitated bigtime, ultimately stalling. I limped it back into the driveway where it stalled each time I tried to start it. I had some pending engine too rich and misfire codes, which I cleared.

I pulled and cleaned the MAFs (pretty dirty), and replaced the plugs (definitely needed it). The car starts, idles roughly for 1-2 seconds, then stalls. I can keep it running roughly if I ease on the gas, but it stalls right after I let up.

My first thought was one of the CPS. Car is under extended warranty, so it will be going in to the dealer tomorrow, but I'm curious if anyone has any other ideas. I'm guessing it isn't the fuel pump/relays as it will continue running if I give it gas. I unplugged the MAFs and it seemed to run a bit longer, but still stalled.

Also of interest was my last trip to the dealer, as the car started slightly overheating. I assumed thermostat, but they supposedly replaced the fan clutch, and told me one of my cats is clogged. The temp gauge went to 2/3 3 miles down the road after picking it up. I took it back and they told me it was because of the clogged cat, and that they would replace it for $2800. I laughed my way home, and have some high-flow aftermarket units on the way. I hadn't driven the car since then. Could it all be related? On a side note, is the big nut on the crank fan an integral part of the fan clutch? Mine is quite rusty, which is curious if it's all one unit and mine was just replaced.

Any insight would be appreciated, as I'm not sure I trust what the dealer is telling me.

Chris

Not sure how much help I can be, but with all that rain, I am thinking water in the fuel/problem with fuel pump??

Also, there is an old discussion about water getting into the brake reservoir (under the drivers side air filter) and water getting into the motor (I think). It was from a member in NY and/or Long Island as I recall. You might want to look at that to see if water is getting in.

I wouldn't bother even trying to start it if it is under warranty, let the dealer sort it out.
Regards,
Jerry
 
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My m5 sat for about 2 weeks as I was away. There were significant storms while I was gone, so there was a lot of moisture around the car.

I started it up and had no issues beyond a slightly hunting idle (seems to be a regular occurance now), but the car hesitated bigtime, ultimately stalling. I limped it back into the driveway where it stalled each time I tried to start it. I had some pending engine too rich and misfire codes, which I cleared.

I pulled and cleaned the MAFs (pretty dirty), and replaced the plugs (definitely needed it). The car starts, idles roughly for 1-2 seconds, then stalls. I can keep it running roughly if I ease on the gas, but it stalls right after I let up.

My first thought was one of the CPS. Car is under extended warranty, so it will be going in to the dealer tomorrow, but I'm curious if anyone has any other ideas. I'm guessing it isn't the fuel pump/relays as it will continue running if I give it gas. I unplugged the MAFs and it seemed to run a bit longer, but still stalled.

Also of interest was my last trip to the dealer, as the car started slightly overheating. I assumed thermostat, but they supposedly replaced the fan clutch, and told me one of my cats is clogged. The temp gauge went to 2/3 3 miles down the road after picking it up. I took it back and they told me it was because of the clogged cat, and that they would replace it for $2800. I laughed my way home, and have some high-flow aftermarket units on the way. I hadn't driven the car since then. Could it all be related? On a side note, is the big nut on the crank fan an integral part of the fan clutch? Mine is quite rusty, which is curious if it's all one unit and mine was just replaced.

Any insight would be appreciated, as I'm not sure I trust what the dealer is telling me.

Chris
I am betting vacuum leak
Our cars are getting old enough that the vacuum lines are getting dry-rotted
 
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I am betting vacuum leak
Our cars are getting old enough that the vacuum lines are getting dry-rotted
i don;t know if i buy the dry rot thing just yet, these cars are 5-8 years old. I just replaced the vacuum hoses and cooling hoses on my 150k mile, 3/90 production e34 M5. They were in pretty rough shape, but not horrible. bmw uses some good rubber.

I'd vote on fuel delivery, pump, relay something like that.
 
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Either
-fuel filter
-fuel pump
-fuel relay
-fuel injectors

BTW did I mention this problem has got to be fuel related??
 

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Discussion Starter #6
LOL! I will check on the fuel issues today before I send her out. I don't think it's a vacuum leak, but I'll give it another once over for any obvious holes/etc in hoses.

The fuel tank is fairly low (50 miles range left), so mabe some moisture did get into the fuel.

I'll update this thread once I find anything.

Chris
 

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Discussion Starter #7 (Edited)
I think we have a winner!

As I said before, I cleaned the MAFs, replaced the plugs, I even cleaned out the oil separators (filthy btw). On a hunch, I went and fillde a 5 gallon tank with some 93 octane and fillde up my tank. The car had shown a range of 50 miles and 1/4 tank left (no reserve light). She briefly protested, then started right up.

At least I got some new plugs out of the deal! I'm going to go change the oil and then go for a joyride.

Thanks to all who helped. Time to see if I can get one or both of the fuel senders replaced next time I'm at the dealer.


Chris
 
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