Ever since I replaced the engine..

[Flash635]

...in my 1986 635, the fuel usage meter hasn't read correctly and the mpg and distance to empty on the OBC are extremely optimistic.
It's also effecting the trans controller.

Obviously there's an incorrect fuel use signal coming in but the engine is running properly.

Nothing in the wiring was changed, just engine out - engine in.


Edit>> It's not effecting the trans controller, that was a broken earth wire near the fuse box.

[Flash635]

The fuel use thing isn't effecting the trans controller like the code said, it was an earth wire near the fuse box.

[JRanmann]

the fuel usage meter....if the (otherwise known as one's) gas gauge is reading optimistically too, then it's likely an intermittant grounding in the return wiring harness, from the tank sending unit up to the cluster's fuel level input.

I am checking the LHD ETM for your year but it's being slow and cumbersome retrieveing the data and it seems now I also need a password. I Will post again if I can trace that wire for you back to front but again you have a RHD vehicle mate, so you best do that yourself or i might just might 'steer' you in the wrong direction!

Cheers~

Ran

[Flash635]

Thanks Ran. My ETM is for LHD as well, I don't think they do a RHD one.

I'll check the tank sending unit, I was in there a few weeks ago tracking a gas smell and might have done something.

Before the engine change the gauge wasn't always working the way it should.

Hang on, you're talking about the gas gauge, I'm talking about the mean specific fuel usage meter that's under the tacho.