Speedo not reading!!
 

First off I'd like to say hi! I'm new to the forum and this is my first post.

I have a 92' coupe with an early black top SR20 swap. For some reason the speedo doesn't read. It lights up fine and everything, just doesn't pick up. I'm pretty sure its the VSS, but i don't know which one to use. Do i need the SR or the KA speed sensor??

Thanks!
Ben

you need the ka speed sensor because the sr20 one reads for a jdm kph speedometer. Figured I'd answer this one since its a simple answer and everyone else would just say search it or Im not spoon feeding you when it just takes as long to answer the question!!!!!!

Incorrect. KmPH and MPH doesn't matter. It's the same signal.


Match the generation to the gauge. Match auto or manual to the transmission.

I don't know if your SR20 is manual or auto. If manual, use S13 manual VSS. KA or SR doesn't matter. It's the same.

check under glove compartment and see if yellow with green stripe is wired correctly. if not maybe sensor is not plugged into lower harness

sorry for the late response! thanks guys! i'll check the wiring first, if that all checks out i'll order the KA speed sensor!

Thanks again!

Incorrect. The wire under the dash goes from the speedometer to the ECU. You need to check the 2 Vehicle speed sensor wires from the lower harness to the body harness and to the gauge cluster.

Are you lazy or do you just not know how to read? There is no difference between KA and SR sensors.

oh my mistake sorry. Why do you have to be rude about it?

thanks for the info though. I'm pretty new to the 240 game.

why am i wrong?? the guy is saying that his speedo is not reading. his car has an sr20 swap which means the plug under glove compartment has to be wired up to read coolant, rpm, speed, etc. if it was never wired during the swap, then it'll never read. i also mentioned wiring from vss to lower harness. so why was i wrong??

Stay here for at least one year and you will understand why. We discuss this issue weekly, if not daily.

The "plug under glove compartment" is the white plug next to the ECU plug. This plug has:

- thermal transmitter (for coolant gauge) from engine to this plug to dash plug and to coolant gauge

- tach signal from ECU to dash plug and to tach

- converted VSS signal FROM the speedo to the ECU.

The 2 VSS wires go from the lower harness to the BODY harness, around the body and then to the speedo. The speedo displays the speed and converts this alternating current into a digital signal and sends that converted signal to the ECU.

The wire under the dash does nothing for the speedo, and actually does not need to be hooked up to the ECU.


We discuss this at least once a week. Open an FSM or learn by searching. Either way, stop talking smack and learn.

OKAY smart kids, the vss sensor on the transmission is wired into the lower harness and actually goes into the the dash, from the DASH HARNESS FROM THE CHASSIS harness, the dash takes and converts the VSS and then outputs to the ECU, so yea a civic guy can read the fsm....

For the third time, the speedo not displaying speed has nothing to do with the VSS wire at the dash plug. You can remove this wire from the ECU and it will not affect the speedometer.

I take this as a compliment. Thank you.

i never said it would affect the speedometer if the wire in the dash was removed, your correct because the wire in the dash WHITE PLUG in side the glove box is the OUTPUT FROM THE DASH TO THE ECU, YES out from dash into ECU,

DASH HARNESS PLUG BEHIND THE DASH would be the dash plug i am refering to , so if his speedometer is not working, then YES first ensure the VSS is INSTALLED in the transmissiona and pluged into the harness, DOESNT MATTER IF ITS A US (twin cam s13) OR JDM HARNESS the body (chassis) plug is the same wiring, but i dont remember if the rev light is wired the same.. and that the LOWER TRANSMISSION harness IS INSTALLED and plugged into the chassis harnesses by the fuse box in the engine...a and if all is right speedo shoudl work, and if not you need to double check the cluster plugs BEHIND the cluster... ( redundant) and if its plugged in maybe you have a bad guage or trace the wire from the cluster plug to the engine bay!

I know it wasn't you who said it. Sorry if you misunderstood. I just wanted to be clear for the rest of the people.

Correct.

Nissan moves the reverse light switch wires around depending on year and transmission. You can't always assume that they're in the same place. It's best to find the plug on the shell and hardwire that to the lower harness.

Nissan also moves the VSS wiring around. Most likely the VSS is not even plugged into the right plug.

You can't match the lower harness by plug. You have to match by wire. Figure out what each wire does on the body and lower harness. Mate them together however you want.

If you try to match by plugs then it may plug in but most likely it won't work. Plus you'll have a few plugs that have no mate.

thanks a lot guys! heading out to storage to take a look at everything today!

I did search btw, but couldn't really find the answer i was looking for.

Thanks again!
Ben