Died while driving, now crank-no start

[Nightowl]

Hey folks, I'm a new addition to the site and am hoping to get some help troubleshooting my new-to-me E46 M3. I've read a number of past forum posts, but thought I'd share the full story of my experience to see if anything stands out as unique.

I picked up a 2001 E46 M3 at the end of July from a younger lad, and immediately drove it 460km / 285 miles home. Unfortunately, it died on me twice during the drive home, about 45 min into the drive. When it died, the gas pedal went completely dead, and I just started to coast to a stop. Both times, I didn't have cell service, tools, or anyone with me, so my only options were to flag down help or wait a bit and try to start it again. Thankfully, after ~10 min of waiting, I managed to start it up and get it rolling.

After two instances of that, I made it to a pull-out with cell service and texted the seller, who suggested blowing dust out of the MAF sensor. That seemed to get me the rest of the way home, including a stop to fill up the tank. I drove around town for 2-3 days afterward, and the issue didn't recur. Unfortunately, on the 5th day of driving around town, the car died again, and I managed to coast into a pullout at the bottom of a hill (power steering went out too). Now, it will crank but not start, even after having waited a few days and getting it towed home. I did some investigating and thought it was the fuel pump (Died with 1/4 tank of gas, and I couldn't hear it priming but confirmed it was getting power and had ground), so I replaced it. Sadly, no luck.

I'm planning to replace the fuel filter next, but wanted to check in here and see if there's anything I'm missing. I've checked the EKP relay, the DME relay, and am going to check fuel pressure at the filter before replacing. Appreciate any help or suggestions!

[Cubieman]

An inaccurate and/or completely faulty MAF sensor should not prevent the car from running, the car will run with it unplugged.

I would use any form of scan tool you have to hopefully get some information.

This is a wonderful tool was created by a forum member, you just need a KDCAN cable and a laptop.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/355301-mss54-ds2-tool-free-tool-for-programming-dme-tune-full-binary-flash-counter-etc

You would think fuel delivery or something simple that would prevent the engine from running altogether, could be a clogged fuel filter, but also could be 100 other things.

Unfortunately checking for fuel pressure/delivery volume on these cars isn't as easy as the valve is under the car by the filter and the valve is not a standard size.

I would read codes, I'd bet you find something that points you the right way.

[sapote]

1. the seller, who suggested blowing dust out of the MAF sensor. That seemed to get me the rest of the way home, including a stop to fill up the tank.

2. I did some investigating and thought it was the fuel pump (Died with 1/4 tank of gas, and I couldn't hear it priming but confirmed it was getting power and had ground), so I replaced it. Sadly, no luck.

1. Blowing dust out of the MAF? No air filter? was it covered with dust? Did you unplug the MAF cable doing this? Blowing dust off should not help it at all, but the act of unplug the cable probably did the trick.

2. Before blaming the fuel pump, one should use the cluster display to read the fuel volume in the L and R tanks, when gauge shows total 1/2 tank or less. If L is more than R tank then the pump is running weak with the worn motor brushes. If R is more than L then pump is perfectly healthy.

To do: use the free app INPA to read the DME error codes, probably many of them in there.

[Slideways]

Hey folks, I'm a new addition to the site and am hoping to get some help troubleshooting my new-to-me E46 M3. I've read a number of past forum posts, but thought I'd share the full story of my experience to see if anything stands out as unique.

I picked up a 2001 E46 M3 at the end of July from a younger lad, and immediately drove it 460km / 285 miles home. Unfortunately, it died on me twice during the drive home, about 45 min into the drive. When it died, the gas pedal went completely dead, and I just started to coast to a stop. Both times, I didn't have cell service, tools, or anyone with me, so my only options were to flag down help or wait a bit and try to start it again. Thankfully, after ~10 min of waiting, I managed to start it up and get it rolling.

After two instances of that, I made it to a pull-out with cell service and texted the seller, who suggested blowing dust out of the MAF sensor. That seemed to get me the rest of the way home, including a stop to fill up the tank. I drove around town for 2-3 days afterward, and the issue didn't recur. Unfortunately, on the 5th day of driving around town, the car died again, and I managed to coast into a pullout at the bottom of a hill (power steering went out too). Now, it will crank but not start, even after having waited a few days and getting it towed home. I did some investigating and thought it was the fuel pump (Died with 1/4 tank of gas, and I couldn't hear it priming but confirmed it was getting power and had ground), so I replaced it. Sadly, no luck.

I'm planning to replace the fuel filter next, but wanted to check in here and see if there's anything I'm missing. I've checked the EKP relay, the DME relay, and am going to check fuel pressure at the filter before replacing. Appreciate any help or suggestions!

If it is cutting out at a quarter tank of fuel, there is a good chance the plastic clip for the siphon jet tube on the driver's side fuel sending unit is broken.

Info in this thread - https://nam3forum.com/forums/forum/m...ausing-misfire

[Cronenberged]

Fuel relay in the trunk

[Nightowl]

An inaccurate and/or completely faulty MAF sensor should not prevent the car from running, the car will run with it unplugged.

I would use any form of scan tool you have to hopefully get some information.

This is a wonderful tool was created by a forum member, you just need a KDCAN cable and a laptop.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/355301-mss54-ds2-tool-free-tool-for-programming-dme-tune-full-binary-flash-counter-etc

You would think fuel delivery or something simple that would prevent the engine from running altogether, could be a clogged fuel filter, but also could be 100 other things.

Unfortunately checking for fuel pressure/delivery volume on these cars isn't as easy as the valve is under the car by the filter and the valve is not a standard size.

I would read codes, I'd bet you find something that points you the right way.

I learned as much as soon as I started looking into the issue when I got home, which makes me scratch my head a little as to why the previous owner would suggest that.

I've got a basic OBD2 scanner that comes back with 0 DTC, both when the car died on the drive home and now that it won't start. Good to know about that tool, I'll have to source a non-Mac laptop.

I ordered a fuel filter along with the fuel pump, so I was mostly just going to check pressure before swapping it out to see if it might give me a clue before I get into it.

[Nightowl]

1. Blowing dust out of the MAF? No air filter? was it covered with dust? Did you unplug the MAF cable doing this? Blowing dust off should not help it at all, but the act of unplug the cable probably did the trick.

2. Before blaming the fuel pump, one should use the cluster display to read the fuel volume in the L and R tanks, when gauge shows total 1/2 tank or less. If L is more than R tank then the pump is running weak with the worn motor brushes. If R is more than L then pump is perfectly healthy.

To do: use the free app INPA to read the DME error codes, probably many of them in there.

Does have an air filter, but the MAF sensor was pretty dusty. Previously, the car sat in a barn for a number of years, so a few things are pretty dusty, in addition to the car coming from a pretty arid part of the country.

I learned about the fuel volume menu after I had already ordered the pump, and was surprised to see 7L in the left, and 9L in the right. Replaced the fuel pump anyway to try and be proactive, and I'd already ordered it.

[Nightowl]

Fuel relay in the trunk

Looking into fuel pressure at the filter and replacing the EKP are my next steps. I've already got a new filter, and an EKP module on the way.

[Nightowl]

So, a small update: I popped the air intake elbow off and sprayed a quick spritz of starter fluid into the airbox. The car started for a moment before dying, which confirms it's a fuel issue (I also unplugged fuse 54 ahead of time to be sure to isolate the test).

Before I sprayed starter fluid in, I had a peek into the airbox, and think it looks like there's a bit of a residue/ gunk in there. Any chance this would indicate that the previous owner was using starter fluid gratuitously to keep it running?

[Cubieman]

Thats a film of engine oil, normal.

[jayjaya29]

Agree with cubie.

[Nightowl]

Beautiful, thank you both!

[sapote]

Looking into fuel pressure at the filter and replacing the EKP are my next steps. I've already got a new filter, and an EKP module on the way.

I'm low on these parts will fix your problem. I'd check the fuel pump 12v supply (2 larger wires) during the first 2 or 3 sec when key turned on, and if no 12v then maybe EKP is bad assuming there are no errors on EWS to DME comm (verified using INPA). If 12v is good and pump not running then bad pump. I don't think a clogged filter bad enough to prevent engine from starting.