Speed sensor, no clue whats going on.

[FredK]

If I understand this correctly, since you have a 88+ 325i the road speed signal is already wired to the e30 c101 at pin 14, right?

[Jason89i]

If I understand this correctly, since you have a 88+ 325i the road speed signal is already wired to the e30 c101 at pin 14, right?

yes.

[EtaSport]

yes, since I have an 87 it was not in the c101. I thought I took care of it when I wired in my c104, but it didnt. I might have sent that wire to the wrong place though. Oh well, it works now.

[devinwwu]

K guys i kinda glanced up into the gauges last night and saw no green plug???
I had one plug right behind the speedometer but it wasn't green...

It's an 86 325 but it had the eta 5k rpm motor. Anyone have a pic of which plug or wire i need to tap into, i would like to get this fixed tonight so the car will finally perform to its full potential.

[devinwwu]

if i'm reading this right i would have to tap into the speed sender (#10)?? or is it a different wire in this diagram.

[EtaSport]

did your car come with cruise control? thats the wire your looking for. If you have anything attached right behind the actual speedo thats probably it. Its one wire.

[devinwwu]

i didn't have cruise control,

[EtaSport]

okay.. well looks like your on the right track by taping into the speedo wire at the cluster. you should have the same affect. If you cant find the wire, ill try to look at the etm.

[devinwwu]

k guys i found the speedo wire and tapped into it but i can't seem to get the right wire in the c101. What is the code i'm looking for??? I am thinking the motronic RXD but i don't know what RXD stands for...

Or if anyone knows what the wire colors are on a 91 535i ecu pinout i could tap into it at the ecu plug

[EtaSport]

Thats the diagnostic connector, you wont find what you need there. The code for it on my car was 1d for vehicle speed signal not present. RXD and TXD are read and transmit data lines I believe. I have not verified this, but I think they search the modules looking for faults and throw up codes.

I dont know if I've got the e34 diagrams, but I will check for the wire color and location.

[devinwwu]

thanks bud i really appreciate it!! i just realized that was diagnostic... oops

[devinwwu]

alright guys i figured it out. the c101 pin for an 87 325i speed sensor signal wire is #14 and was black with a white stripe on my car. (i had to use the 325i harness for my swap in order to use the e34 m30 ecu) i tapped into the speed signal from the back of the 325e speedo which is brn/red and ran it to the black/white wire.
This had nothing to do with my fuel cut. in the process of swapping from electric throttle control on the e34 to the mechanical needed on the e30 chassis i didn't think about the throttle position sensor. When i pushed the pedal down past a certain point it would cut because the throttle was already full open. the tps would cut power as it cannot give any more air through the tb. so i just needed to adjust the screw under the gas pedal to set the WOT pedal position and make sure i couldn't exceed it.

[Bill 84 318i]

Just did some t-shooting on this, since I'm throwing a VSS code too.

On my 1990, the wire coming out of the back of the speedo is blue/yellow. I followed it through the dash over to the blue connector (CC control unit?) above the ECU. Doesn't looking like the wire physically goes anywhere else, and there was continuity between the ends. I checked for continuity between the speedo wire and every single wire at the C101 (bottom, e30 side), and I couldn't find any that seemed to work.

I'll be splicing the speedo wire into the black/white wire from pin 42 at the DME, and crossing my fingers that it's going to work.

[PiercedE30]

anyone have the e34 NV wiring diagrams they can share..........i have aparently lost/not bought the wiring cd when i got my ETK and TIS, etc. PM if you can email it or are willing to give me a link.

[Mohammed_A]

Im confused.... im also getting the road speed sensor fault, i have an 86 model e30 with s50b30, please help someone....