E30 320se 1990 speed signal *URGENT*

[alangorst]

Hey everyone I'm wondering if anyone can tell me what wire from the back of my speedo should connect to my speed signal wire from ecu?

Thanks Alan

[jmc330i]

It should be a black wire from a blue plug at the back of the speedo to pin 9 of the E30 engine loom plug.

[DanThe]

Thats RPM, Vehicle speed is Pin 14 C101 and Black/White

[jmc330i]

Sorry, my bad. Word blindness after a day in the sun. Could of sworn the OP asked for engine speed

[alangorst]

The problem is that my cars revving out at 5300 revs. My speedo works but I have been told it was a wire from the back of my speedo I'd need to connect to my ecu. It's a 3208 have with a m52b28 in it if that helps any?

[Grrrmachine]

Is there any chance that your car was originally a 4-pot before you did the engine swap?

[alangorst]

I have no idea as I didn't do the conversion

[Grrrmachine]

Let's clear up some words then. By "speedo" do you mean speedometer, rev counter or the entire instrument cluster? Is your car actually revving to 5300rpm, or it's just the rev counter SAYING that? If it's the rev counter that's playing up, what rev does it show at idle?

[alangorst]

I mean speedometer. I got told I needed a brown wire with red trace from my ecu (pin 15) which I have found and it's not connected to anything. I got told this wire should connect to a wire from the back of my speedometer which would give me a speed signal and let the car rev fully. I believe the rev gauge to be correct I don't know exactly what it revs on idle but it's around 800.

[Brianmoooore]

Road speed signal to the engine ECU comes from pin 10 on the white cluster plug on a blue/yellow wire to pin 14 of the C101 engine loom socket.
When an E30 engine is fitted, the wire on the engine loom side of the C101 changes to black/white.

[alangorst]

Mine has a m52b28 in it.

[alangorst]

What's the white cluster plug? / where's it situated ?

[Brianmoooore]

Mine has a m52b28 in it.

Presumably with an E30 plug on the end of its engine loom, so it's still pin 14!

[Brianmoooore]

What's the white cluster plug? / where's it situated ?

On the back of the instrument cluster!

[DanThe]

Road speed signal to the engine ECU comes from pin 10 on the white cluster plug on a blue/yellow wire

Not all E30's are fitted with this wire, ive been exchanging pm's with the op and have pointed out everything thats mentioned in this post.
The best advice as ive already said is to check what you have in Pin 14 of the C101, and go from there....

[Brianmoooore]

Not all E30's are fitted with this wire, ive been exchanging pm's with the op and have pointed out everything thats mentioned in this post.

The primitive engine Ecus fitted to early E30s would have no use for this signal, so it's logical that the above is true.
If the wire's missing at the cluster, then it will need to be added, and possibly the cluster changed as well, if it turns out the signal isn't present at pin B10 anyway.

[Grrrmachine]

That shouldn't be the case with a 1990 320i though, surely?

[Brianmoooore]

That shouldn't be the case with a 1990 320i though, surely?

Correct. Certainly should all be there on this car.

[alangorst]

Right sorry for being daft but if it comes from pin10 on the white cluster plug can I just take it straight from there onto ecu wire? (Novis I know)

[Brianmoooore]

It would work if you bodged it like that, but what's the point? Unless someone's been doing some very strange things to your car's wiring, there will be a blue/yellow wire in the body side of your C101 20 pin engine loom connector, connected to pin 14, carrying the required signal, and on your modified M52 loom the required wire to connect it to shouldn't be far away on the plug side of the C101.

[alangorst]

That's the thing haha I don't really know what's going on with wiring. Everything seems to work bar this. Ill have a look and try and find this wire. I have found the one from ecu that I need to connect to it atleast. Thanks very much for the help gents