Weird tach problem 180sx tach in a 240sx sohc gauge cluster

[Eli]

so i swapped my 1990 tach out and put the 1992 180sx tach in.

I started the car up to test to see if it is ok.

here is the problem, When i turn the key to accessory mode, the tach automatically jumps to around 1000 rpms, Then when i start it, it reads 2500 rpm for the idle.

what can be wrong?

can i not use the 180sx tach in my 240sxz gauge cluster??

another intersting thing is I plugged up the whole 180sx gauge cluster and when I turned it to accessory mode the speedometer also jumped to like 10kmh and the tach jumperd to 1000 rpms

what could this be?

is the gauge cluster bad or is there some way to recaliberate the gauges?

[180fan]

are you using the rpm sensor from the sr or from the ka? If you're using the rpm sensor from the sr with a sr tach, that should be fine. If you're using some other combo, it's not going to work, or will give strange readings.

[Supafly]

assuming your old motor was a SOHC, you can't use that tach with the SOHC tach signal. the DOHC and SOHC motors have different tach signals and would cause the wierd readings you're getting.

[f150intally]

Are you running the KA or SR motor? I'm assuming SR since this is in the SR forum.

- Jay

[Eli]

Hey guys Just wanted to let you know that i am running a sr20. So what you are saying is that although I have a sr tach, well the whole gaugecluster for that matter, that it still will not work If the rpm sensor was used instead of an sr's? so where is this rpm sensor and how can I tell the different between a sr one and a sohc KA one. THanks

[quiksilvia]

if u have a sr in the car then the transmission is gonna be from a sr unless u swapped it out. with the sr transmission and the sr guages it should work fine. but u said that u were using a 180sx gauge cluster, maybe if ur running a redtop with a silvia ecu the tach from a 180 wont read right. make sense?

[f150intally]

I have an 89 s13 chassis (sohc) with the Blacktop sr20det and a tach out of an SR20det equipped japanese car (not sure whether silvia or 180sx) and mine works just fine.

[SpeedRacer1]

Dont listen to what anybody else just wrote. (except for F150)

The Speed sensor has nothing to do with the tachometer. The tach signal comes from the ECU and has no direct sensor that I can find.

Quik, Silvia cluster = 180SX cluster, they are the exact same parts.Silvia ECU = 180SX ECU They are the exact same parts.

The only differences on an S13 Silvia or 180SX is the ECU for 1989-1990, 1994-1996, 1997-1998.

Tachometer differences, 1989-1990 CA18DE(T) tachs should work on an SR. 1997-1998 S13 180SX Tachometers will not work on USDM S13's with rewiring the connectors. So if you are trying to use this cluster you need to rewire...

[quiksilvia]

i was talking about his kmh prob sr1, just thinking aloud...

[vlow1210]

i have an s14 sr20det in a 89 240sx. will any s13 jdm 180sx/silvia cluster work? (except 97-98 180sx cluster)