M3 No Crank No Start

[B.Squared]

I came here looking for ideas. I have searched several times with no real answers that have worked. I have a 1998 BMW M3 convertible. Automatic transmission. It was running and then set for a year and now no crank no start issues. Dash lights up and ac controls work. I did replace the battery in case it was that weak. I have bypassed EWSII and put in an ECU with EWS delete just in case and that didn't change anything. Starter wasn't having any issues or clicking like it was going out when it was parked. Key isn't spinning endlessly. Since it's OBD2 I don't think the crank sensor has gone bad, but I guess it could be an option? I had that issue on my 1995 M3 once but it would still crank if I remember correctly. Could it be the ignition switch? I did stumble across some issues with that on e46s but didn't see anything on the e36. I have not verified that the starter is getting power when the key is in position 2, so that's my next step, but wanted to see if anyone else had some ideas in case it's not getting power. I did check fuses and they all appeared to be good. Any help is appreciated!

[scooper]

Ignition switch could be the issue but maybe more likely is the starter solenoid. You'll need to remove the TB and other parts to test the starter solenoid but space is so tight there.

I have read that a bad crankshaft position sensor code could cause rough running or prevent a start, but I have also seen youtube vids which depict a disconnected CPS yet their vehicle still started. Based on this I think the CPS is not critical to starting the vehicle.

[ScotcH]

but I have also seen youtube vids which depict a disconnected CPS yet their vehicle still started. Based on this I think the CPS is not critical to starting the vehicle.

Ummm, don't think so. car will NOT start or run without a Crank sensor. It will run without a CAM sensor. Anyway, it will still crank ether way so that's not the issue.

[mike.bmw]

Could this be a transmission-related thing? Does the auto trans have to be in "Park" to start the car? (Similar to how the clutch has to be pressed in to start an E36 with a manual trans).

Try shifting it through P-N-D a few times, if that's possible with the key in.

[scooper]

park or neutral to start.

[B.Squared]

I believe it has to be in park, but I did try in neutral as well. Very possible to be the crank sensor. I had that go out on my 95 M3 before, but I have never heard of the OBD2 ones going out, but always a possibility. Thankfully it's close to the starter so I can test both while I'm in there.

[JitteryJoe]

I believe there is a switch at the gear selector that signals when in park. Could that switch be bad or somehow disconnected? I'm not that familiar with the automatic but I see a switch on the shift assembly called a "neutral safety switch". Does it perform the same lockout as the clutch switch on the manual? Someone here should know.

[RBNetEngr]

Neutral safety switch and clutch lockout switch essentially do the same thing. Clutch lockout switch will not let the engine crank unless the clutch pedal is depressed; neutral safety switch will not let the engine crank unless the gear selector is in Park or Neutral.

But the OP said the symptom is CRANK but no start. So the neutral safety switch would not be the cause of his issue with Crank but No Start.

Have you checked and verified Fuel and Ignition? First verify that you have both of those.

Do you have a OBDII scanner to read any codes or test sensors?


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