wont rev past 4k!!

[JayGotti]

yea so my buddy has a e34 m50 single vanos and it doesnt past 4k under load. and revs to redline in neutral. ive read that it could be the cps but he replaced it and tht wasnt the problem. he also has a little leak on the manifold on the second piston area, could that be the cause of not revving past 4k under load?

[evandael]

did he wire up the VSS?

[JayGotti]

did he wire up the VSS?

what is vvs?

[JayGotti]

what is vvs?

you think the speed sensor could cause this?

[evandael]

VSS is the vehicle speed signal. the M50's DME needs to see a road speed before it will allow it to rev past a certain RPM.

i forget the c101 and x20 pin #'s but IIRC, this is a common cause for his issue.

[future rs]

Sounds like he is R3v limited...

[AlpineM325]

Sounds like he is R3v limited...

Haha that it seems.

[JayGotti]

VSS is the vehicle speed signal. the M50's DME needs to see a road speed before it will allow it to rev past a certain RPM.

i forget the c101 and x20 pin #'s but IIRC, this is a common cause for his issue.

i have a 413 dme and if the vss doesnt work will the speedo work?

[e30rapidic]

vehicle speed sensor

ecu needs a signal from the back of the cluster. Lots of info on here regarding it

[JayGotti]

vehicle speed sensor

ecu needs a signal from the back of the cluster. Lots of info on here regarding it

i was in his car trying to help him trouble shoot it and it basically acts like a 2step in gear. sometimes it passes 4k in first gear to like 5.5k, and sometimes in neutral it goes to redline and sometimes it does the 2step at 6 or 7k.

[JayGotti]

the signals from the c104 connector goes to the harness, are those 2 wires the vss? both tach and speedo work

[graphikg]

Try disconnecting the vanos from the harness and driving it under load. If that allows the car to go past 4k, then it is Vanos and timing perhaps.

[JayGotti]

found the problem it was the vss thanks guys!!

[MaxBell]

Can you please post what you did to hook up the VSS? I heard it being said in various places and no one ever gives a SPECIFIC wiring tutorial.

What wire (color, location) did you start at? Which wire (color, location) did you connect to?

EDIT: Ok I got serious and pulled the wiring diagrams and things for my early model with a 1995 M50 in it.

Here you all go: http://www.r3vlimited.com/board/show...23#post3459423

[evandael]

what joy, a happy ending.