1987 325 will not rev over 4k VSS Questions

[mph10909]

Alright lets start it off with

I have a 1987 325 pre facelift, that i have completed an m50 swap on.

My current ongoing problem is no being able to accelerate my car over 4,000 RPM's. I have read this is due to my VSS not being correctly hooked up to the DME.

The problem I am having is that it states to hook pin 14 on the body harness to pin 14 on the engine harness (no big deal) the only problem I am having is my vehicle does not have a pin 14 on the body harness.

Also it does not have the green connector i would be able to tap into on the gauge cluster.

I have read that it will possibly be relocated to a C103 connector inside of my glove box which is a three pin connector.

The this is I have read that those three wires control

*Tach
*Fuel Economy
* and this one I am not sure of but states the powering of my old DME.

So my question is whats right wrong and what should I do?

Should I find A cluster that has the green electronics board attached,
should I find just the board and plug it into my cluster and wire it to the engine harness ( where can i even find one)
Or is it the three pin connector, and which wire is it (there is a black that I know is for Tach a green one or a yellow one)?

Thanks for your guys time hopefully I can get this thing accelerating past 4K.

Also everything is new all gaskets, plugs, pumps, cam sensors, cranks sensors knock sensors, vacuum lines ect so all that nonsense has been cancel out from my problems list.

Mike,

[EclipseMTL]

Bumping for answe. Having same problem in an 86 es.

[evandael]

http://www.wedophones.com/Manuals/BMW/1987%20BMW%203%20Series%20Electrical%20Troubleshooting%20Manual.pdf

the glovebox connector you speak of is the c104. pin 1 (black) is for RPM, pin 3 (white/yellow) is for MPG's. the VSS.. good question. i had previously assumed that you could tap into pin 26 (brown/red) on c3 (yellow connector on back of cluster), which sends the speed signal to the OBC. now i'm not so sure.

[mph10909]

Thank you for that response that is something I have not heard about while reading up on stuff I'll dig into it and see what I can find.

If anyone one else has some inform that would be appreciated.

[mph10909]

I just wanted to say thank you on that information. I tapped into the brown red wire from the OBC computer and attached it to pin 14 on the engine harness and so far so good lower idle and no more 4k rev limit.

[frankie591]

Yup plenty of places to splice into that signal. I tapped into it at pin 26 of the yellow plug on the back of the cluster and ran the wire through the firewall at the fuse box.

[evandael]

I just wanted to say thank you on that information. I tapped into the brown red wire from the OBC computer and attached it to pin 14 on the engine harness and so far so good lower idle and no more 4k rev limit.

great! you're welcome. i suppose i'll be doing the same when i wire mine up.

[JayGotti]

Yup plenty of places to splice into that signal. I tapped into it at pin 26 of the yellow plug on the back of the cluster and ran the wire through the firewall at the fuse box.

so if i tap in to the obc wire where do i run that to? i also dont have pin 14 (87 325)

[frankie591]

so if i tap in to the obc wire where do i run that to? i also dont have pin 14 (87 325)

pin14 on engine harness

[JayGotti]

pin14 on engine harness

on the e34 side right? do you know the color of the wire btw?

[frankie591]

nope. etm's should have it, or if you cut the x20 plug off you should be able to look at that and match up what wire goes to pin 14