hatch 240 cluster vs coupe cluster? (speedo doesn't work w/ analog and digital)

[892jz240]

what is the difference between the hatch 240 cluster and the coupe cluster? I have a problem with my speedometer. i tried both the analog and the digital clusters and on both the speedos don't work. everything else works fine. i took a look at the harness and notice that the analog has a lot of wires missing compared to the digital but has one wire that the digital doesn't have at one of the pins in the connector that plugs into main harness. it is pink but i don't remember the tracer (stripe) color. Does the male connector in the main harness contain all the pins for both style clusters? If so, then what could be the problem with my speedo being inop? i changed my speed sensor, ecu, and cluster, and nothing fixed it. any ideas?

[180fan]

not much is different but you do need the harness that runs behind the dash to the cluster.

[892jz240]

Okay. i put a digital cluster together out of two. Now the speed shows zero when you turn the key to the on position. When you start the car, it displays 13MPH. Any idea what that could be?

[180fan]

wrong signal going to the cluster. did you get that harness that runs behind the dash along with it and verify the different wires running to the cluster?

[892jz240]

hmm. interesting. gotta try that. I used a cluster from a dohc and one from a sohc to make the speedo work. I have the harness for both. gonna try swapping see what it does.

[892jz240]

OK. Swapped the harness. There is no difference. thing is when i rev the engine up a bit the speed goes up to like 26mph. weird huh? could it be that i am using a sohc tach on a dohc cluster?

[892jz240]

Update to issue. The cluster displays correct speed while driving. Only displays incorrect speed at idle. I was driving around for some time and it stopped doing it. it started back up in the moring displaying 7 mph at idle car not moving. when you rev engine, signal changes. could it be a ground issue. I don't know but i think it is something related with engine rpm ground which is probably going backwards through the speedo to get ground. funny thing is it doesn't do it while driving. only when you are standing still.