2006 M3 Starting Issue 71k Miles - Need Help

[k3nny]

Hello Fellow Members - I've been having starting issues with my 2006 6-speed manual e46 m3 with 71k miles and I'm hoping someone can chime in or point me to the right direction.

Scenario: This problem only started occurring recently and it's happened about 10 times already. But basically I never have any issues at all cold-starting the car even when it's been sitting for 24 hours and up to a week. The problem occurs when I do the following:

• Successfully cold start the car and drive the car for 10-15 minutes; approximately 1.5 - 2 miles (I live in NYC).
• Go back to the car after 5-10 minutes of running errands and attempt to start the car. The car turns over and instantly dies. Then I would attempt to restart it 3 additional times and then maybe on the 4th try, it finally turns over and idles successfully.
• Drive around town again, turn off the car, run some errands, return to the car and the car starts instantly.

I honestly have no idea what's wrong with the car. Again, this issue only happens on the second start after returning from errands. Usually, any starts afterwards are fine.

Maintenance is up to date and I recently replaced the following:

• Brand new MAF Sensor (less than 50 miles)
• Brand new 950CCA Battery (less than 200 miles)
• Spark plugs were changed 5k miles ago
• VANOS work completed 4k miles ago
• I tried starting the car with two different sets of keys thinking maybe it's the immobilizer chip (no luck)

Background on the car:

• I never had idle or sputtering issues with the car
• Everything is stock besides AutoSolutions SSK

Any insight would be greatly appreciated.

[benzthis]

I had a situation where my car would start fine on the first try then later in the day take 2 or more tries and that never happened.a couple of days later it just didn't start because my fuel pump died.so yours could be on it's way out.

[ATB88]

I have, in the past, fixed this issue with a new fuel pump. That's pretty expensive, though, so I'd suggest testing fuel pressure before thinking about dropping $500.

[heinzboehmer]

I also experienced a similar issue and it ended up being the fuel pump. Second the suggestion to check fuel pressure first. Also Radium engineering makes a more affordable alternative than the OEM pump: http://www.radiumauto.com/Fuel-Pump-...6-M3-P314.aspx. Requires more work though.

[simon_c]

If you have a manual car this could be an issue with a bad clutch switch. When you have a bad clutch switch you will push in the clutch and try to start the engine and but the car has issues recognizing that the clutch is engaged and so won't turn the car over. It's an easy, and relatively cheap ($80ish) part to replace.

Link to part: https://www.fcpeuro.com/products/bmw...le-61319122700

[heinzboehmer]

If you have a manual car this could be an issue with a bad clutch switch. When you have a bad clutch switch you will push in the clutch and try to start the engine and but the car has issues recognizing that the clutch is engaged and so won't turn the car over. It's an easy, and relatively cheap ($80ish) part to replace.

Link to part: https://www.fcpeuro.com/products/bmw...le-61319122700

The engine wouldn't turn over with a faulty clutch switch, so sounds like that is not the issue in this case.

[pawelgawel]

sounds like 2 possible issues, fuel or timing. vanos was done and most likely it would show while running if anything was loose, so most likely like the other guys say, pump. Did you replace the filter yet? maybe its a clogged filter.. pumps usually don't fail at this mileage in my experience.

[simon_c]

My experience is that the clutch switch may not be completely faulty but on it’s way out. This would make it so that sometimes the car would turn over and sometimes it would not (took a lot of tries).

This may not be the case for the OP but it was for my specific scenario! Glad it was one of the easier fixes for me but thought it may be a good/simple place to start.

The engine wouldn't turn over with a faulty clutch switch, so sounds like that is not the issue in this case.

[ragnar]

+1 on fuel pump

[simon_c]

I didn’t read the OP closely. Didn’t realize that it turned over then died. Sounds like a fuel pump issue in this case as others have mentioned.

[Jersey_M3]

Is the radium alternative fuel pump any good, I have a very similar issue and suspect it to be the fuel pump?

[heinzboehmer]

Is the radium alternative fuel pump any good, I have a very similar issue and suspect it to be the fuel pump?

I would personally stick with stock if you're not going for an upgraded pump. The Radium kit is very well made, but does require you to mess with wiring that will end up inside the fuel tank. Adds one more thing that could fail if not checked and maintained frequently.

[ATB88]

I would personally stick with stock if you're not going for an upgraded pump. The Radium kit is very well made, but does require you to mess with wiring that will end up inside the fuel tank. Adds one more thing that could fail if not checked and maintained frequently.

Seconded. I've seen situations where people upgrade to the radium pump in order to fix a fuel pump issue and then end up still having an issue and getting a new stock pump anyway.

[k3nny]

Thank you all so much for your replies. I'll keep an eye out on the fuel pump.

@pawelgawel fuel filter has not been replaced yet but I did purchase one last week and it's waiting for replacement. I'll go with the easy options first and hopefully it addresses the problem. Praying it's not the fuel pump, but these cars are showing it's age so I understand.

[Albertan]

Next time you figure you are in a hard start position, just turn ignition on leave for 5 seconds, turn off then on for 5 seconds then off and then try to start. Could be you are not holding pressure in system. Or you could also test via tire pressure gauge.
Only other thing could be temp sensor in manifold if it says car is cold it might be flooding it a bit when starting when warm.