sr20det speedometer not working (noob)

[Dima1127]

hey guys im new to this so please dont bash, or do i dont care you will just be ignored.

on to the problem at hand i bought a 240 with a swapped sr20det (first 240) and the speedometer isnt working its a 89 and used to have a sohc in it, the previous owner said that with a sohc cluster the speedo worked but the odometer didnt so he swapped a dohc cluster in and everything but the speedo works, could it be my lower harness just needs to be swapped if so please tell me to what harness i need to swap it to.
any input is appreciated

-Thanks, Dima

[240sxHernandez]

1st thing I would do is look at some wiring schematics. If everything works but the speedo, I would definitely keep an eye on the speed sensor it self and its circuit/wiring.

[Dima1127]

Well the speed sensor works since the speedo works on a sohc cluster, iv been doing some research but didnt get all that in depth cuz it was last night and I think it said that on a sohc and dohc harness the Ecu vss pins are different numbers

[KiLLeR2001]

Swap the speedo from the SOHC to the DOHC cluster. Problem solved, that's what I did when my DOHC speedo started going bad. If you have an SR20DET you have to use the DOHC tachometer.

[Dima1127]

killer im a bit confused right now, i have a dohc clsuter in there and the tachometer works but the speedometer it self doesnt. could you please elaborate on what you mean?

[Mikester]

killer im a bit confused right now, i have a dohc clsuter in there and the tachometer works but the speedometer it self doesnt. could you please elaborate on what you mean?

WHat he means is that it's awesome that you have a DOHC cluster because you need it for the tachometer to work properly...

Then he went on to say that you need to physically remove the speedo from the DOHC cluster, and replace it with the one that was in the SOHC cluster.

Now that's assuming the previous owner wasn't bullshitting you. If you've never physically SEEN the speedo working, don't assume it ever did.

My thought is that the speed sensor isn't properly wired in the system. If I were you, I'd pay the 90-100 bucks for a fresh, plug & play lower harness from www.wiringspecialties.com (http://www.wiringspecialties.com) and call it a day. The lower harness from there supports everything from auto/manual swaps to SOHC & DOHC... Quite nice.

[Dima1127]

mike thats actually what im in the process of doing right now,
but i think im just going to get a lower harness, less hassle and new wiring always looks so nice and is reliable, question is im not sure what harness ill need?