Hello BMW friends! Having a crank no start issue on my touring. It sat a few days then didn't want to start again.
The car:
1995 520iTouring 5speed Manual
Siemens MS40.1 ECU
M50b20Tü
I verified the starter is working.
Coilpacks are firing.
DME relay is working as intended.
Fuel pump runs about 5 seconds with ignition on. I tested the Fuel Pump Relay it is working as intended. However on pin 85 of the FPR, I get 12v when the fuel pump cuts out. It is my understanding pin 85 is grounded by the DME then the FP will run. I am unsure what to look for next.
It appeared that the Crankshaft position sensor was defektive, I replaced it with a new one from BMW. There was no change.
I tested the wires from the Crankshaft Sensor plug back to the DME plug, with all 3 being ok. I also get the 5v on pin 2 as it should be.
I tried with another DME 5wk9002 MS40.1 with the starter wires at the EWS module bridged and the green wire pin 7 on round plug cut.
A side note - With the original DME 5wk9003 MS40.1 the pin 85 FPR would ground for a split second everything else remained the same. I had been planning on deleting the EWS as it has caused me headaches in the past.
Any ideas would be appreciated!
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5wk9002 MS40.1 DME is without EWS
( can't seem to edit original post)
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Leave the EWS and DME and the crank sensor alone. You have spark: this means the DME and EWS are happy, and the crank sensor knows engine position and speed. Put everything back to stock, then test again for spark, so that we have a baseline.
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You tested to see that the fuel pump works, but you haven't check fuel pressure. Test fuel pressure. Just because the pump is making noise doesn't mean you have correct pressure.
You need 4 things to start the engine: Fuel in the correct amount, air, spark, and compression/
Last edited by bmwdirtracer; 01-09-2019 at 09:51 PM.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
All back to stock, spark verified with spark tester. Sounded like it really wanted to start, but wouldn't catch.
Fuel pump is not priming, Pin 85 on FPR is not being grounded by the DME, only for a split second at ignition on. FPR & DME Relay are new from BMW.
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I made a jumper for the FPR with a fuse and a switch. Switched on there is a high pitched squeal from under the intake manifold. I narrowed the source of the sound to the idle air control valve..it squeals loud for 2-3 seconds then makes a noise like it is adjusting itself. Could the DME be cutting the FPR off because of a malfunctioning IACV?
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Go to www.newtis.info to make sure you’ve wired the jiumper properly. Also, check for power at the fuel pump when cranking the engine.
Thanks for the response but I'm past that already.
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The original post said that the fuel pump runs for 5 seconds with ignition on. Is this correct?
When you hot-wired the fuel pump relay, did the car start?
Are you really very sure that you're checking the correct relay? BMW does move them around, year to year...AND sometimes someone's been there before, and moved the relay slots. Have you checked the wire colors at the relay plug?
If the car didn't start when you hot wired the fuel pump relay, then the problem isn't fuel.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Did you fixed it? Having same issue here
Welcome to the forum!
You do yourself a disservice by posting on this five year old thread, likely about a different car,with different behavior and details. I'd suggest that you start your own thread, and provide exact details for your car (like year, model, engine, transmission, mileage and recent work done), and then describe the problem, whether the starter turns , whether you have spark, etc.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
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