BMW m54 camshaft position sensor

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jofriedl
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BMW m54 camshaft position sensor

Post by jofriedl »

Hi,

I'm in the process of building building an e30 rally car with an m54 swap. I'm running MS3X. I'm trying to keep things as simple as possible by running the ignition as COP waisted spark. I want to integrate as few of the OEM sensors as possible, mostly because I can't find the necessary literature on how to wire them. The crankshaft position sensor on the M54 is a siemens unit and has been particularly problematic. Bench tests are inconclusive in determining wether the thing is a hall sensor or a VR sensor. Also I might have fried it in the process. I ordered a crankshaft position sensor for an M44 engine a few minutes ago because they are definitely VR sensors and simply bolt in place.
After my complete and utter failure with the crankshaft position sensor, I'm wary of fiddling with the Camshaft position sensor without some kind of advice. Can anyone tell me the correct wiring and trigger angle for the intake camshaft position sensor? Thanks!
grom_e30
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Re: BMW m54 camshaft position sensor

Post by grom_e30 »

i know that bmw did use a certain type of sensor on some engines that was neither a hall or a vr sensor some king of hybrid thing, i want to say that is was the siemens unit if i remember correctly.
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
jofriedl
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Re: BMW m54 camshaft position sensor

Post by jofriedl »

Thanks for the reply!
Yes according to the documentation bellow, (see page 27) the hall sensor used for the crankshaft position sensor is a 'dynamic' hall effect. Have no clue what that means but I can tell you that it won't plug and play with megasquirt. Now I just need to figure out the wiring for the VR sensor I just ordered......

http://www.bmwclub.lv/files/Tab_3_M54_Engine_X5.pdf
DaveEFI
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Re: BMW m54 camshaft position sensor

Post by DaveEFI »

It appears to output a conventional square wave so should be possible to get MS to read it. You might have to add a pull up or pull down, though.
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jofriedl
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Re: BMW m54 camshaft position sensor

Post by jofriedl »

Well the sensor came in today and the difference is size between the stock hall and the replacement VR presents another question. They are both the same diameter but the stock sensor is a good 3/8 of an inch longer than the replacement VR. How far must the sensor's tip be from the teeth to reliably read a signal?
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Re: BMW m54 camshaft position sensor

Post by jsmcortina »

jofriedl wrote:Well the sensor came in today and the difference is size between the stock hall and the replacement VR presents another question. They are both the same diameter but the stock sensor is a good 3/8 of an inch longer than the replacement VR. How far must the sensor's tip be from the teeth to reliably read a signal?
Typically around 1mm.

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Paul_VR6
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Re: BMW m54 camshaft position sensor

Post by Paul_VR6 »

Gurov posted that he got the m54 crank sensor to trigger ms using v3 opto modded for lo to high with a 750-1k pullup to 5v. Worth a shot.
-Paul
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jofriedl
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Re: BMW m54 camshaft position sensor

Post by jofriedl »

Thanks for the replies! After realizing the parts company sent me the wrong sensor :twisted: ... I did some testing on the stock sensor, rewired it and got the engine to fire. It idles very rough and looses sync every second or so. Won't go above 1000rpm about. I know there's a multitude of reasons that this could occur, but I just can't seem to get over BMW's description of their sensor-'Dynamic Hall'. I'll try what Paul-vr6 suggests before ordering a new sensor.
DaveEFI
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Re: BMW m54 camshaft position sensor

Post by DaveEFI »

Why call anything a plain hall effect when you can add dynamic to the description? :D
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Peter Florance
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Re: BMW m54 camshaft position sensor

Post by Peter Florance »

I'm pretty sure the cam sensor is hall type
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jofriedl
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Re: BMW m54 camshaft position sensor

Post by jofriedl »

The cam sensor is definitely a standard hall type. This week I hope to figure out when the sensor fires so I can run sequential injection. I've called a few dealerships but no one seems to have that information. I'll have to pull the cover off the head and measure it myself.
jofriedl
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Re: BMW m54 camshaft position sensor

Post by jofriedl »

Great news! Paul-vr6 was right. I was able to make the stock m54 crankshaft position sensor work with MS3x by feeding 5v from pin 26 on the main board through a pull up resistor of 1K ohm to the sensor input on pin 24. After soldering the wires in place, I was very skeptical and hit the start switch half expecting to fry the board for one reason or another. I was so surprised when she ROARED to life that I instinctively hit the kill switch. (partly because a significant vacuum leak sent the RPMs up into the 3k range). Thanks for all the help guys! :yeah!:
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Re: BMW m54 camshaft position sensor

Post by Paul_VR6 »

Glad to hear that it worked!
-Paul
1992 Corrado SLC 3.6 VR6 11.38@120 - MS3 Pro Ultimate - Microsquirt I/O - Can EGT - Racepak IQ3s
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