Tach Connector Pin Out

[JoeyBones]

ok guys, my tach isn't working and i've taken everything appart. The si lights work so the batteries seem ok...all solder points on the si board and on the back of the tach look good.

I'm now trying to see if i'm getting signal from the dme and have no idea which pins to check in that blue connector. Does anyone have a diagram? I downloaded the electrical troubleshooting guide and the pages i need seem to be missing.

btw its a 91 318is...

[JoeyBones]

nobody?

[JoeyBones]

PLLLLEEAASSEEE... haha or point me in the direction?

[b*saint]

Ah its easy. Just find the dealer service manual.

[Jean]

I had it somewhere, still looking...

[JoeyBones]

I'm trying to download what I think is the dealer manual...the electrical trouble shooting manual I had didnt have the pages needed....just my luck.

[StereoInstaller1]

Look at different years, as not much changed on the car...so like the '87i has a ton more info than the '90 or '91

[JoeyBones]

jeeze nothing there either...ok i'm going to download something older...

[george graves]

Here ya go This is from an 87 - I didn't check all the years to see if there were radical changes.

[JoeyBones]

ok now we're getting somewhere... just trying to figure out how this translates to the plug... excuse my ignorance...I'm a mechanical engineer, I avoided electrical stuff for a reason!

am i reading right... c1 pin 7?

[george graves]

Yep. It's a black wire - BUT - it's shielded most of the time - so it might be a gray color. At least on my car, the shielded wire is usually gray. I assumed you already knew what plug as c1?

[JoeyBones]

yea the blue one correct?

[george graves]

Lol - I'd have to hunt through the diagrams. Do you need me to? Or are there enough wire color there you can do process of elimination?

[JoeyBones]

haha i was saying C1 is the blue connector on back of cluster. I'm just going to use a meter and see if i have a signal coming from there at all. If not, check continuity from there to DME. If no continuity, then wire is screwed...if there is continuity, possible bad DME, or bad CPS? I actually don't know how or what sensor the DME get's the engine speed, but assume CPS.

just trying to trace it out before i go buying and replacing stuff.

[StereoInstaller1]

The tach wire is black and is not shielded at the IP: after it comes out of the DME it does not need shielding.

My dead tach was all about the cold/dead solder joints. My clumsy hackery with the solder stick fixed it right up!