can't get my tach to work!!

[bahlorm]

Hey everyone new member here. I have a 1990 240sx that was pre-built with an sr20det. I bought it from a friend of mine who bought it from the builder. My friend said that he was driving down the road and his whole gauge cluster went out at the same time. He bought a new cluster which didn't fix the problem. I just went ahead and ordered new gauges and I'm trying to wire them with no luck. I was told the red and yellow wire going to the ecu is the tach signal but there's no signal coming from it that my aftermarket or even old tach registered. I also tried a white wire that I was told is the cas wire which also has no signal. All my fuses are good. I'm at a loss on what to do.

[demi.colwell]

Bumping.. Still getting no where with this.

[bahlorm]

Little bit of an update with this. I got my water temperature gauge wired up and working properly.. Tach still has no reading at all, wired directly to the yellow/red coming out of the ecu.

[brndck]

you just grabbed a random yellow/red wire? did you bother looking at an ecu pin-out to make sure its correct? what tach are you using? some aftermarket tachometers require using a pull-up resistor, or a tach adapter like the one autometer makes.
http://autometer.com/img/products/9117_d.jpg

[demi.colwell]

No I used a pin out and used the tach signal wire. I believe number 3 pin. I am using this cheap 4 in 1 tach. Got the water temp to work on the gauge. My stock gauges also didn't work. Since I autocross this not having any gauges at all was worrying me a bit.

[brndck]

No I used a pin out and used the tach signal wire. I believe number 3 pin. I am using this cheap 4 in 1 tach. Got the water temp to work on the gauge. My stock gauges also didn't work. Since I autocross this not having any gauges at all was worrying me a bit.

Soooooooo maybe look into figuring out why the stock ones don't work instead of using aftermarket ones as a bandaid?

[jr_ss]

Yeah, god forbid you do some investigative work to repair broken shit.

These don't work, I'll just buy another gauge...

[demi.colwell]

Because if it was possibly a cluster problem then some new gauges would of solved my issue. Plus if it was anything to due with the wiring under the dash I can eliminate that by trying to connect it straight from the ecu. I'm not an electrician and I'm far from a mechanic. Which is why I come on here for assistance on what could be going on.

[jr_ss]

There I obviously an issue some where. You have to trace the cluster wires anyway, so why not see it there is something screwed up in the original wiring.

[Trap Star]

Sure you got the right wire? There's two red and yellow wires right next to each other.

One is Red with a Yellow stripe.
One is Yellow with a Red stripe. This is the tach signal wire.

It would be pretty easy to mix them up.

[lucas240sx]

Ok I'm going to bump this old thread so I don't have to start another one
I've been searching on the for hours now

I have a 89 s13 with sr swap
When I put in a working tach....it will work for about 15min- 20 min then just stops working
Why?

I know the yellow/red wire is for tach.....I tried to trace the wire from dash plug/ecu pin through the engine harness (spare harness that's been cut up), looks like it goes towards the plugs by the stock battery location?

I've read ppl just connect a wire from the tach to the ecu.....which sound no different from the factory route?
Or connecting to the cas 180° white wire

I hope someone can help me with this

[bahlorm]

Connecting it to the white cas sensor didn't work for me. I had to run a wire to the ecu.

[lucas240sx]

I don't understand why that would work when a wire is already going from the ecu all the way to the plug on the back of the cluster

Are you putting a wire from the screw on the cluster to the ecu?

[bahlorm]

I have an aftermarket tach. My whole cluster wasn't working. But if your tach was working then just stops randomly I would assume something would be involved in a loose wire.

[lucas240sx]

The whole cluster works
Once I did see smoke coming from behind the cluster and tach stoped working

Tried another cluster....tach worked
While I was adjusting the cas, I went to check the tach and again it stopped working

They never work again Untill I put a new one in

[lucas240sx]

Does anybody have any input in this matter?

[lucas240sx]

Bump anyone