Crankshaft Speed Sensor need help

[joedir1]

Does anyone know if a faulty crankshaft speed sensor on my 1994 540i can cause the DME to not talk to the main motr and fuel relays causing no fuel to pump and the car not to start? thanks.

[E34-520iSE]

That's correct - No crank sensor signal means the engine won't start.

HTH,

Shaun M

[joedir1]

does the same goes for the camshaft speed sensor?
I know for sure the car will not start if the oil level sensor does not work.
thanks

[E34-520iSE]

Can you tell us exactly what's happening here? Are you suspecting that your cam sensor and oil sensor are duff too? I don't know about V8's but my M20 will start no matter what the oil pressure sensor says

[joedir1]

Well here it goes...car stalls one night. Tow to dealer. They notice a wire is burned up and recommed new wire harness...$ 2500 installed. Only paid $ 2000 for car. Got it home and replaced the one wire that went to the oil level sensor. Car starts right up. Dealer did say at time that either camshaft or crankshaft sensor showed a fault, but at that time car did start so we just kept driving. 2 months later car stalls and barley makes it home. So since not so confident in dealer, we start to check it out. Replace some relays, and oil level sensor since it was burned up. Car still will not start, even though I know fuel pump works as I by passsed relay. Put in new main relay also and still no start. THough about it more today and remember the fault the dealer mentioned. Since we put in a new camshaft sensor, the only one left is the crankshaft sensor. THANKS alot. my kid is really bummed out with out his ride...and I cant give up on it. Its a really cool car.

[Ross]

A bad crank position sensor will cause a no start because of no spark. Sometimes they can be brought back to life briefly with a well placed blow to the sensor.
If your no start is because of no spark the CPS could be the trouble.

[Bill R.]

know that the pump works because you took the hose off and bypassed the relay and gas came out... did you hook up a gauge to verify how much pressure was there?





Well here it goes...car stalls one night. Tow to dealer. They notice a wire is burned up and recommed new wire harness...$ 2500 installed. Only paid $ 2000 for car. Got it home and replaced the one wire that went to the oil level sensor. Car starts right up. Dealer did say at time that either camshaft or crankshaft sensor showed a fault, but at that time car did start so we just kept driving. 2 months later car stalls and barley makes it home. So since not so confident in dealer, we start to check it out. Replace some relays, and oil level sensor since it was burned up. Car still will not start, even though I know fuel pump works as I by passsed relay. Put in new main relay also and still no start. THough about it more today and remember the fault the dealer mentioned. Since we put in a new camshaft sensor, the only one left is the crankshaft sensor. THANKS alot. my kid is really bummed out with out his ride...and I cant give up on it. Its a really cool car.

[joedir1]

I did not check the presure. The bypass tool that I made with a toggle switch and fuse ran the pump from the stop where that fuel pump relay goes.
I was just happy to see fuel come out of pump. When I put the relay back in the holder, no power at pump plug. This is why I replaced the DME main relay and still no power at plug. thanks for the replys...I appreciate the help....and my kids hockey team just played and tied the # 3 team in state....so all he needs now is his old Bimmer running.

[whiskychaser]

I was just happy to see fuel come out of pump. When I put the relay back in the holder, no power at pump plug. This is why I replaced the DME main relay and still no power at plug.
Maybe I missed something, but you only get power to the pump when the engine is running or being cranked

[joedir1]

I only have been able to get power to the pump when I use the bypass tool with toggle switch. Click switch on and I hear E-box fan, and pump sends out fuel. ( I saw it as I unhooked fuel line from pump) So as Shaun M said above, no crank signal, no message to DME to power up? I have replace a few sensors now and am willing to replace this one too, just trying to be more sure. Appreciate the commets....thanks ahed of time to all.

[E34-520iSE]

Does your car have the 'stomp test' cluster? That might throw up some diagnostic error codes for you. Just search on here for 'stomp test' and all will be revealed.

[whiskychaser]

I only have been able to get power to the pump when I use the bypass tool with toggle switch. Click switch on and I hear E-box fan, and pump sends out fuel. ( I saw it as I unhooked fuel line from pump) So as Shaun M said above, no crank signal, no message to DME to power up? I have replace a few sensors now and am willing to replace this one too, just trying to be more sure. Appreciate the commets....thanks ahed of time to all.Of course you can leave the fuel pump relay jumper in and see if it starts. The relay needs to receive a switching voltage so if you are not getting that when cranking I'd certainly be looking at the CPS as has already been stated. Particularly as I dont recall you saying you were getting a spark

[joedir1]

I am not sure if my car has the stomp test cluster, but I am charging battery right now so I can try it later tonight. I will have to read up on how to check for spark. If it is pulling out a plug and setting it on ground and turing over the car, I think we can handle that. I also found the 1994 E34 electrical trouble shooting manual and will start to sift thru the pages to figure out what no power to fuel pump relay. I was thinking about trying to start the car with the toggle, but did not want to damage anything. thanks for the comments from both of you......I really appreciate it.

[632 Regal]

you say you need to charge the battery... the car will not start with a low battery even though it may crank. Battery should be fully charged first. If the fuel pump is working it should hold pressure and start but only run a short time. As stated above use the jumper for the pump to see if it starts.

No deal in laying the plug on its side to check spark on these babys, need to pull a coil pack and ground it then lay the plug on something...bit of a chore.

[joedir1]

thanks. I am going to try to start from bypass tool after the I fully charge the battery.
I also found stomp test instructions and will try that to see if the crankshaft positon sensor fault shows up. really appreciate the comments. cant give up on it...very scared to tow it to the dealer.

[joedir1]

tried stomp test twice and no luck. not sure if car not equippped or I did not do test correctly. any ideas? do have a fault tool, but wish I did. about how much should one cost?

[632 Regal]

stomp test is a pain sometimes. First time I could never get it to work, took a few days off and tried again and got it the 3rd try. Have to be real fast and make sure it goes to the floor every time. 2 times and gave up? sheesh dont be a quitter! LOL


tried stomp test twice and no luck. not sure if car not equippped or I did not do test correctly. any ideas? do have a fault tool, but wish I did. about how much should one cost?

[joedir1]

Ok thanks for the boost...may be a silly question, but my directions from the bmw4life site say that " fault codes can be read by turning the ignition key on"...and according to my wiring diagrams this is the first position (1) is the accessory position and the (2) is the run position. Which would you recommend to try this test? Also, silly again, but I can not confirm if the check engine light on this vehicle is the oil can with a drop of oiling coming out of it. thanks again in advance everyone.

[632 Regal]

2nd light from the left next to battery says check engine, key must be in position 2 "run" must stomp 5 times to the floor in like a microsecond it seems. Just checked it and took me 3 tries to get it to blink whats 1213? new to me lol.

edit: 1213 is O2 #2 ill reboot the computer and not let the thing idle til it gets warm or I change the intake gaskets again

Good luck

[joedir1]

ok thanks...I will look more closely at the dash to find it. yea fault 1213: O2 sensor 2 lean/rich c/s...

[joedir1]

well the reason I can not see the battery or check engine light is because they do not light up. I will check Bently book to see if there are bulbs in there that can be replaced or ?
Side Note; not sure what it is called, and was told by dealer that it is only available when you buy the whole wire harness. It is black plastic piece with a metal center and 240 ohms marked on the outside. It is connected on a brown wire, assume a ground. Any idea what this is and if it being broken can be causing some problems? Since we bought this a year ago, I dont recall the batt and engine lights working, but the dealer did say that this piece may mess up the dme. It has been running great up until this recent shutdown. thanks,Joe

[joedir1]

:D Replaced crankshaft speed sensor and the car started right up. THanks to all who weighed in on this one. I really appreciate it. Other things to work on, but at least it is back on the road.

[632 Regal]

Buy a set of new bulbs and replace all, it has 3x 3watt guage illumination 6 x 1.5 watt bulbs for LCD illumination
13 x 1.2 watt bulbs idiot lights. The 3 watt bulbs are discontinued with the new part # 07119905358 I had a couple bulbs left over maybe from different dash clusters.

Have no clue about the 240 ohm thing your speaking of but the bulbs burn out over time.

[angusbn]

Is this the crankshaft speed sensor (aka pulse generator) - item #3 for a 89 535i (m30)?

[E34-520iSE]

Looks like one to me