540i cranks one revolution and stops. Will not start

Measure the depth from the bell housing mounting surface to the tooth face with the depth gauge. Then measure the distance between the sensor mounting surface and the end of the sensor. Subtract the two.

I understand that, I need a depth gauge that can rest on both sides of the sensor hole. Ill try and borrow one Tom. If the distance is to far what the hell do I do about that?? FYI to anyone who is following this NEVER BUY A JB RACE FLYWHEEL. Only use oem or uuc v12 setup.

After measuring carefully like 100 times it seems that I have a gap of 1.04mm with the shim. The shim is only .32 mm so that brings me down to .72. What do you think I should do? Grind down the sensor?

thank god I have a Toyota for my second vehicle...

It's bul****. The sensor is in within the spec without the shim. I just tried to start it and have the same symptoms...

is it possible that the flywheel is indexed incorrectly?

I sure can't help anymore, BUT, did the car start normally before the flywheel and clutch replacement? If so, the work and/or parts have something to do with it.

If the DME does not get the correct signal from the crank sensor, the car will not start. There are some smart scan tools out there that can monitor the crank sensor signal. It would be prudent to check that before pulling the trans.

Originally Posted by neonphire8604

1998 540i M62 non vanos engine

I just finished replacing the clutch and now the car wont start. It will crank for what sounds about 1 revolution and cut out and continue.When it cuts out the steering wheel will go up and down as if the ignition switch is shut off and on. The thing that puzzles me the most is that it will crank normally if I unplug the crank sensor.

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Hi,

the cranking will stop if the speed of the engine is too low during cranking. The engine speed is measured by the crank sensor therefore when you disconnect this sensor, the "cranking speed monitoring" function will shut off and let you crank as long as you want.

Now the question is why is the cranking too slow?
Either the resistance of the engine / crank shaft is too high (unlikely) or
this is an electrical issue. High resistance (= bad contact) in the main path from the battery to the starter. Or the starter itself. Did you remove starter cables during clutch job? Are these tightened correctly?

Thank you for your response. I did not unhook the starter cables, I simply unbolted it and pushed it back. According to the wring diagram the only thing that can interrupt the starting circuit is an Anti-theft device so what you are saying does not make a whole lot of sense to me...

The anti theft device (EWS) communicates with the engine control module for many reasons before and during cranking. Some conditions have to be met in order to start up the car. The start signal for the starter motor is driven by the EWS but this doesn't mean that EWS is the only decision maker there.

Ok, I understand what you are saying. I have been trying to watch for rpm on my scan tool while cranking but it loses communication a couple seconds in. should I be checking for network issues like module powers/grounds and can lines?

Originally Posted by neonphire8604

Ok, I understand what you are saying. I have been trying to watch for rpm on my scan tool while cranking but it loses communication a couple seconds in. should I be checking for network issues like module powers/grounds and can lines?

You might wanna check the ground for the engine control module (on the engine side under the right cabin air filter - visible) but I don't think this is the issue. Loosing communication during cranking is not a surprise, that happens because the supply voltage drops for a while.

I would check the battery first even if you think it's fine. Then cables, connections, tightening nuts.
Get another car with strong battery and jump start your car on the top of the engine. Also the negative cable has to be connected to the engine block.

i just rechecked all of the connections in the trunk, to the alternator, the starter and the ground that goes to the passenger side motor mount and they are all fine. I have a 900cranking amp battery pack connected to the engine hook up's and a brand new battery in the car and it cranks plenty fast until it cuts out. If you truly believe it is a starting system problem, the car should pop start right?

Originally Posted by edjack

I sure can't help anymore, BUT, did the car start normally before the flywheel and clutch replacement? If so, the work and/or parts have something to do with it.

If the DME does not get the correct signal from the crank sensor, the car will not start. There are some smart scan tools out there that can monitor the crank sensor signal. It would be prudent to check that before pulling the trans.

sorry, I didn't see your post. I drove the car right into the garage so it started and ran just fine before this whole ordeal. This thing is just a nightmare.

I really do not think that I have any issues with my starting system. Is this an acrurate diagram for my car? It was built on 11/97. it seems to be missing the cruise control module because I assume the DME handles it on the throttle by wire models.

Listen to this start up how much faster the healthy cranking happens:



this is why I think the issue might be related to the starter system.

On your video do you keep the key in the start position constantly? Is the crankshaft sensor connected at that moment?

There is no mechanical blockage around the replaced parts right? Nothing that would make turning the crankshaft harder?

Connect the engine block to the chassis with a thick cable to make sure the grounding of the engine is o.k.

It was cranking fast like that the first time I cranked it with the brand new battery.I had ran my new battery down to like 11.5 volts, then I put my fully charged jump pack on it before shooting. I was holding the key steady. The crank sensor was hooked up which is why you can here it cough once and a wile and I heard my spark tester ark too. All of my voltages are within a 10th from the battery to the alternator lead on top of the motor to the starter. The cables are 100% free of any corrosion and are all tight. Unless the engine block itself is a bad ground I do not see how I have an issue here.

I spun the motor over by hand several times when I was examining the tone wheel on the flywheel, There was no abnormal resistance.

I will unbolt a bell-housing bolt and stuff a 4 gauge wire behind it and bolt it to the chassis ground location once my jump pack charges. Im kinda screwed though because my battery is now down to 9 volts and I have no charger here...

After speaking with a BMW technician we have come to the conclusion that I probibly did not position the flywheel correctly onto the crankshaft. Since it is an aluminum unit the doll pin probibly was crushed into the mounting face. He said he has seen people do this before. Apparently I'm not the only dumbass on the planet. I will let you all know my findings when I take the trans out again on Tuesday.

ouch...

good luck with removing it again

4th time doing it hahaha. Ill prolly have it out in 1 hour.

It's official! Dumbass of the year award goes to me for putting the flywheel on in the wrong spot. Oops haha.

Stuff happens.

Thanks everyone for your help, I really appreciate it. The car runs great now! Coincidentally none of my previous electrical issues have been acting up.