Classic no tach, econometer. But with a twist.

[Zingabe30]

Classic no tach, econometer. All other gauges and my obc work fine.

It's an 86. Believe it was a 325e originally. Was swapped to a super eta at some point but long ago.

Car runs drives. Performs flawlessly. Except I have to look at a big ugly sunpro tach since my factory doesn't work.

Si board and batteries are good. Confirmed everything's working in another car including tach

I think I've narrowed this down to needing to splice c101 pin 9 to black wire on c104. Here's the problem. I've Hooked the black wire from c104 to pin 9 with no change.

Help. I would love for my dash to function as it should.

I've spent countless hours searching and trying everything commonly suggested on the forums to no avail.

Any ideas? Thanks.

[downforce22]

Try this. http://www.strictlyeta.net/technical/328i_8.html

M20 E to I 2.8 Liter Engine Conversion
Fred Kim

VII. Tachometer Wiring
The very first split out of the wiring harness from the ECU is the C104 connector, which is supposed to run to the instrument cluster. Because the 325e and 325i connectors are different, you'll have to do some splicing or bridging. I wanted to bridge the wires since splicing can be messy and can cause some problems later on for someone else.

If you disconnect the harness from the ECU, you will see 55 pins with the sequence running from right to left, as follows:



Pins 1, 20, and 38 are adjacent to the wires and pins 19, 37, and 55 are on the free side of the connector face.

The two wires that must be bridged from the instrument cluster harness are #6 and #32: Pin #6 is the engine speed output and gives the instrument cluster the signal for the tachometer, while pin #32 is the fuel consumption output and gives the cluster the signal for the econogauge. If you have an OBC with the CODE feature active (and you still want to have it functional), then you'll also have to bridge the wire from pin #38, which is the input signal that enables the driveaway protection. So you'll have to bridge:

- black wire from instrument cluster harness to black wire on engine harness (runs to pin #6)

- yellow/white wire from instrument cluster harness to white/black wire on engiine harness (runs to pin #32).




Once you do that, voila! Everything should work nicely. The OBC, which receives its signal from the instrument cluster, will also function normally afterwards.

Thanks again to Mitch for all the help!

[Zingabe30]

Is that not what I've done by bridging the black wire on c104 to pin 9 on c101. And yellow wire to pin 8 on c101.

Or are the wires you refer to in the instrument cluster not the same as what runs through c101.

[Zingabe30]

And thanks for quick reply

[Zingabe30]

Should the black and white/yellow wire in c104 have power. Both show nothing. But green does.

[downforce22]

You said you connected it to pin 9 and the writeup says pin 19. I connected mine to the wrong white/black wire first and it didn't work

[Zingabe30]

I'll look for another white/black wire today. In another write up it said to bridge it to pin 9 in the c101 round connector in engine bay by fuse box. .

But regardless of that. Shouldn't there be some power in the black or yellow wire of c104. No matter if I connext it right, if there's no power I won't be able to tell if it's working or not.

Where does c104 get its power from?

[Zingabe30]

Still no luck. I'm at a loss. I have no power at c104. Fuel. Temp. Gas and speedo all work. Obc works great, always has. The only things that don't work are tach and econo gauge. All fuses are good.

To reiterate black and yellow wire at c104 have no 12v power at any time. But the green wire does.

Please help. This huge sunpro tach that's screwed into my perfect Uncracked dash is killing me.

[fenwick]

I have same problem! Bump!!!