Ok, what the hell is wrong with my car?

[pineapplegti]

sounds like the wiring harness swap would be my next plan of action . it seems like u have covered everything else..

[MR 325]

Well I finally got a key made for the car so that's a plus.

Guess what, still runs the same, lol.

I guess I will go ahead and swap in another harness unless anybody has any other ideas.

[MR 325]

Before I do this... Will an 87 325is harness work on my 89 motor? i'm thinking yes but just double checking if there are any small differences I don't know about.

[Mike325]

I have heard that the harnesses will work. But still double check.

[riverdale21]

Before I do this... Will an 87 325is harness work on my 89 motor? i'm thinking yes but just double checking if there are any small differences I don't know about.

That harness will work in your car. You may have issues with your tach and econ gauge though. If you go through with the engine wiring swap and these items stop working PM me or dashboardmonkey for a tach and econ fix.

I just finished up with a swap that is the opposite of yours. I put an 89 motor and harness into an 87. Tach and econ gauge weren't working even after trying different clusters and swapping SI boards. Turns out on the 87 chassis instruments have a separate connector plug called C103 in the wiring diagrams that drives the tachometer and economy gauge. For the 87 chassis with the 89 wiring harness I had to run two wires from the C101 to the C103 in the glove box.

Edit: just saw this post was 3 years old. Sweet.

[Axxe]

Did you ever solve your problem? My car has been parked for two years but it still does the same thing when I take it for a boot around the block.

[MR 325]

Did you ever solve your problem? My car has been parked for two years but it still does the same thing when I take it for a boot around the block.

Yes sir, been driving the car for a little over 2.5 years and 20,000 miles since this thread. :)

The fix was swapping my 89 engine harness for one from an 87 325iS.