e34 m57 swap - rpm gauge

[sklenus]

Hi guys,
brand new in this community, just made a swap to my 88´ 524td, put a m57 3.0 diesel engine and also changed the LOW diesel car wiring to HIGH gas wiring with a check control, everything seems working fine, just can´t make a rpm gauge run

do u have any ideas how the TxD and RxD bus signal from m50 or other petrol engines DME looks like

i am able to take square diagram signal from camshaft hall sensor but don´t know if it would work with cluster RPM
was thinking when the speedo just use the pulses from hall sensor in the differential and the cluster makes it run on gauge, so maybe RPM works similar, don´t know if the signal from crankshaft hall sensor is just looped through the DME, or the DME is changing the signal somehow

will be grateful for any ideas

[jc43089]

Not sure about how to get that to work, but awesome swap!! We were never lucky enough to get diesels over here.

[mottati]

would love to see some pics.

[demetk]

Is there a coil? If so the black wire is usually the rpm signal wire to the cluster.

[mottati]

Is there a coil? If so the black wire is usually the rpm signal wire to the cluster.

diesels don't have a coil.

[demetk]

LOL, shows you how much I know about diesels. The DME - it does have one of those? - has no rpm output signal?

[Binjammin]

OP, I dont know much about diesels, but I would guess that the original sensor was hall effect and the new one is vr. Have you tried swapping the old sensor in if it fits? what year is the m57 out of?

[sklenus]

will post pictures later, when will sort them out

the car is former 88´ 524td, now swaped with 91´ 525i m50 car wiring and m57 engine came from 00´ e46
the original hall effect sensor on m50 engine is mounted on the crankshaft flywheel, making square signal 0V or 5V and there are 3 teeth missing on the flywheel to let the DME of m50 engine that one round is finished

the m57 uses DDE (digital diesel electronic) 4.0, it is comunicating with cluster by CAN signal, which is much more complicated I guess, than Txd and Rxd signal coming out od e34 DME to cluster,

as I wrote I can take square signal from camshaft hall sensor and use it raw, or maybe change it a bit (while camshaft has doubled rpm than crankshaft) that is why I would like to know the e34 DME/cluster signal, if it is square, frequency etc

actually i found black wire coming from DDE, the wiring diagram says, it is RPM output, but it is blind end in the OBD II diagnostic connector, I tryed plug it to the cluster pin, but the gauge wasn´t showing anything

I guess the best way is to measure the frequency on operating e34 car, and then try to change the signal or somehow manage it to work

[sklenus]

ok guys, seems I have found a solution, found this thread about RPM signal in later cars,
http://www.e90post.com/forums/showth...=339893&page=2 ,
I assume all the OBD II RPM signals for 6 cylinder engines has the same diagram, but still need to try it with scope on my e39 530d car, it is I believe pin 9 with black wire

but I did some measurement with my friend with scope on m20b25 e34 with the same result of signal diagram https://www.dropbox.com/sh/ayoialcm3ndl4ee/G5HaS9sRiY
the pictures are signal frequency for iddle, 1000rpm, aound 1500-1600rpm and 2000rpm on e34 525i m20

in case the pictures wont work in the future: seems all 6 cylinder engines uses the same RPM signal, around 40Hz at the iddle and then moving up, something around 3 pulses per revolution, as was stated in e90 post, also the pulse in e34 goes from 0V to 14V in pulse, depends on your alternanator, need to measure e39 and later, if they also move like this, or goes from 5V to 14V

will post the result of an e39 scoping soon

[sklenus]

here are som pics of the works, not done yet, but soon

http://sklenus.rajce.idnes.cz/88_BMW_e34_530d

[Smokey Bear]

http://www.rallyraid.co.uk/shop/prod...p?prod=EL_1060

Might be of some help I was planning on buying this.

[GeorgiosM5]

Hello All,
Can someone tell me how can i start the m57n engine on my e34 m5 please? What can i do with the wiring please?
Thank you in advance.. xtremebm2@hotmail.com

[5mall5nail5]

Hi guys,
brand new in this community, just made a swap to my 88´ 524td, put a m57 3.0 diesel engine and also changed the LOW diesel car wiring to HIGH gas wiring with a check control, everything seems working fine, just can´t make a rpm gauge run

do u have any ideas how the TxD and RxD bus signal from m50 or other petrol engines DME looks like

i am able to take square diagram signal from camshaft hall sensor but don´t know if it would work with cluster RPM
was thinking when the speedo just use the pulses from hall sensor in the differential and the cluster makes it run on gauge, so maybe RPM works similar, don´t know if the signal from crankshaft hall sensor is just looped through the DME, or the DME is changing the signal somehow

will be grateful for any ideas

On a 525 its a solid black wire on the DME pin 20 I believe. That's the gauge cluster RPM output from the ECU. Maybe its pin 84 i dunno those two numbers stand out in my mind. Its solid black and works by pulsed ground.

- - - Updated - - -

LOL, shows you how much I know about diesels. The DME - it does have one of those? - has no rpm output signal?

No E34 is driven off the coil, thats very very old school style



Ah crap, old bump