recently did a stroker and rpm/mpg gauges don't work now

[DetailAddict]

so i recently did a stroker with my 87 325e (10/86 production if that matters). everything running great, but my rpm and mpg gauges don't work. at the same time (probably a bad idea) i did a 13 button OBC swap as well. my old and new gauge cluster had rpm/mpg working before and i just swapped them back to double check and neither is working.

i do have some wires hanging... any ideas on what's going on?

Leo

[Gregs///M]

I would first inspect the ETM manual to check your wiring. The ECM sends engine speed to the cluster via the black wire on the blue connector (cluster side.)

Be sure this is receiving pulsating signal by testing with multi meter set to AC volts. Should show 1.5-6 volts with engine running.

OBC shares many wires from the cluster through the yellow connector.

[jlevie]

My guess is that C104 (the three wire connector near the DME connector) isn't present on your engine harness or it isn't hooked up. The tachometer and MPG signals from the DME to the car are via that connector. It was present on harnesses built before 8/87.

[DetailAddict]

Do you mean the three pin connector in the picture I attached?

My guess is that C104 (the three wire connector near the DME connector) isn't present on your engine harness or it isn't hooked up. The tachometer and MPG signals from the DME to the car are via that connector. It was present on harnesses built before 8/87.

[DetailAddict]

thanks to you both and I was able to put the two and two together. the 3-wire connector in the glove box is connected to the black wire in the blue connector to the cluster.

So the question now is which wire do I tap in the ECU harness side?

Leo

[DetailAddict]

okay, so pin 6 seems to be the one... but what's the color(s) of the wire!? i can't take the darn connector apart to trace... :( In Bently 6:48 has no mention of wiring color either... :(

[DetailAddict]

alright! according to this link it's BK! However, there seems to be 3 black wires... :(

Unless someone has a better idea, I think I would have to splice all three and to a continuity test to see which is pin 6...

http://84.45.115.78/e30zonewiki/index.php/ECU_Pinouts

Leo

[DetailAddict]

by logical deduction, i was able to locate the wire in one shot! however, after i put everything back together that's when i realize the mpg/econometer still not working.

according to the site it should be working as long as speedometer and tachometer are working. And it's saying i may have a bad cluster... :(

any clue? i know it was working before...

(I do see a signal in the ecu harness for the econometer, am i suppose to tap into that one as well?)

Leo

[DetailAddict]

think i found it...

http://www.armchair.mb.ca/~dave/BMW/e30/

6210-3 - WT/BK (matches the previous link) from the ECU harness to YL/WT on C1 (blue connector) on the cluster.

If I remember correctly, there is a YL/WT wire in that 3-wire connector where I connect to for the Tachometer. Now I wonder what that 3rd wire is for...

Leo

[downforce22]

I have the same problem. According to strictly eta you need to bridge the black wire for the tach to work and supposedly the same needs to happen for the econometer with the yellow white. I bridged it but it has not been working for me yet.

[DetailAddict]

just did it over lunch time and it's working perfectly right now! :)

Leo

I have the same problem. According to strictly eta you need to bridge the black wire for the tach to work and supposedly the same needs to happen for the econometer with the yellow white. I bridged it but it has not been working for me yet.

Did you do a continuity test from the C1 connector (blue connector from cluster) to the plug in the glove box area? then from the plug to the ecu harness (female end)? I did all that to make sure all the wiring is good. once i plug the harness back into the ecu, battery reconnect, and I was good to go!

Leo