Help installing a tachometer on a 90 gsx

[GettinPaper]

I'm wondering where to tap the green wire for an rpm signal??
Any help will be appreciated.
It's on a 90 gsx by the way.

Thanks

 

[Never Satisfied]

There is a connector under the dash on the drivers side. It is almost on the back of the fuse box. The wire is white and will show AC voltage when tested with a DVOM. Not sure why you are installing an aftermarket tach when you have one stock...

 

[GettinPaper]

There is a connector under the dash on the drivers side. It is almost on the back of the fuse box. The wire is white and will show AC voltage when tested with a DVOM. Not sure why you are installing an aftermarket tach when you have one stock...

Well the stock gauge isn't working in his car,
so were installing an aftermarket one.
So all i need to do is tap into the white wire under the dash behind the fuse box?

 

[94TalonTSI1]

If there has been an engine swap, I assume you're probably missing the square tachometer signal driver that's usually mounted to your Intake Manifold. An aftermarket tach can be tapped in from the coil pack on what I do believe is a green/white wire.

If your stock tach isn't working, I'd look into that.

 

[GettinPaper]

If there has been an engine swap, I assume you're probably missing the square tachometer signal driver that's usually mounted to your Intake Manifold. An aftermarket tach can be tapped in from the coil pack on what I do believe is a green/white wire.

If your stock tach isn't working, I'd look into that.

Well the 90's are the oddball of the dsm group.
And i don't know why the hell the gauge isn't working...
But i'm not trying to fix the stock gauge,
i'm just trying to help my friend hook up a tach so he
know's when to shift..


So, i tap into the green/white wire from the coil pack?

 

[94TalonTSI1]

I could be wrong, however I do believe that's it.

 

[GettinPaper]

I could be wrong, however I do believe that's it.

Can anyone else clarify that this is the best place to tap for a tachometer?
Thanks

I looked at this plug and all the wire's and none of them are green/white.
One's yellow/green and i'm thinking that's it?

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[dsmfa9nutter]

Easier to get the stock one working. Awfully ricer to put in an aftermarket tach when you have a stock tach.

 

[GettinPaper]

I really need help please.
Where should i tap the green rpm wire too?
I've searched and searched and still can't figure it out..
and i've searched and someone said something about the noisefilter
causing the stock tachometer not to work...

 

[Never Satisfied]

The best place to tap it is going to be under the dash at the connector as I mentioned. You have no worries of loose wiring under the hood that way.

Although, as was mentioned, it is probably the one special little piece that the 90 model had that none of the others did. If that piece is missing, you will play hell trying to get an aftermarket tach to work properly.

However, if you absolutely have to put the tach in for him and want to get it to work without worrying about the missing link, go directly to your fuel injector wires. Find the wire that is common among all 4 and you should be guaranteed to get a decent signal.

I would still recommend looking for the other part. Let me see if I can find the link to the page that has all the info on it.

Here it is. The link was actually fairly easy to find, I was looking in to getting a Colt to strip my TSi and put it all in. Here's the info though...

Tachometer Fix

 

[GettinPaper]

thanks for your help,
i'm going to try and tap it into the white wire behind
the fusebox and see what happens.

 

[NeMiZiS]

Been a while but did you get it working?
I'm about to figure out why my tach doesn't work on my 90 Tsi.
If I can't get it working in goes an aftermarket....

 

[ramsack]

Easier to get the stock one working. Awfully ricer to put in an aftermarket tach when you have a stock tach.

Especially ricer to put in a tach when you have a stock one that just isn't working.

 

[hhuricane]

There is a tach connector on the firewall that works perfect for this. It's where I get the signal for my shift light. No need to hack into the harness when there is a connector already there.

 

[NeMiZiS]

There is a tach connector on the firewall that works perfect for this. It's where I get the signal for my shift light. No need to hack into the harness when there is a connector already there.

Do you have a picture of the connector or a diagram?

 

[thomcasey]

Been a while but did you get it working?
I'm about to figure out why my tach doesn't work on my 90 Tsi.
If I can't get it working in goes an aftermarket....

Just order a 90 coil-pack. It comes with the noise filter and your tach should start working.

 

[NeMiZiS]

Oh ok that sounds easy enough.
I'm going to check mine out and see if I have the noise filter or not.
My motor supposedly came out of a 92 and I'm just trying to get it all situated.
Thanks.

 

[steve]

Just order a 90 coil-pack. It comes with the noise filter and your tach should start working.

That is the tach gate not the noise filter. It generates the signal from the switching of the coils by the power transistor somewhat like the 91+ power transistor does directly.

The noise filter attaches to the the intake manifold stay on the back side of the manifold facing the firewall. There are pictures of the filter and where it mount in the archives, just search for noise filter using my ID.

The RPM connector in the engine bay is a tap off the line from the power transistor to the coil for cylinders 1 and 4. Because it's only connected to one coil it see half the pulses.

 

[tsi1991awd]

I had the same problem...my 90's tach wasn't working at all. I had to look down at the SAFC to see the RPM's. I got a noise filter off of a Hyundai 4g63 and it worked like a charm.

For some reason, the previous owner took the noise filter off and the plug on the main harness was just dangling there. I bolted the noise filter to the back of the manifold (since the manifold stay is non-existant) and connected the plug....bingo, worked like a charm.

 

[NeMiZiS]

So I looked behind my intake manifold and found this plug with a wire ripped out.
Is this my problem or is it something else?

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[tsi1991awd]

That plug may be for the A/C if yours is removed...or something else. I know there are a couple plugs that dont go to anything on all the DSMs I have had.

The one for the noise filteer is located behind the intake manifold...it is a tiny square plug, about half the size of the one in the picture you posted. It has two pins inside...one on top of the other. The first one is horizontal and the second one is vertical. It has two small wires running to it.

If yours is actually plugged in, check for the actual noise filter itself....it will be bolted to the manifold stay (bracket) underneath your intake manifold. If you dont have the bracket, then it may just be dangling or non-existant. It is a tiny square piece....most likely brass colored with a black rubbery bottom. Has two wires coming off of it.

The noise filter needs to be grounded to work properly, so that means you will need to bolt it to the firewall or intake manifold if your stay is missing. (which i bolted it to the back of the manifold.)

 

[NeMiZiS]

The plug that is pictured I unplugged to take the picture.
It has two wires going to it and one is cut, but if that isn't effecting the tach I'll worry about it later.
I'm going to look for the noise filter when I get off work today.
If I have one, I'll make sure it is grounded good.

Thanks for the help.

 

[tsi1991awd]

I will try and get a picture of my noise filter and post it here within the next couple of days. It's really small, and if it's bolted under your intake manifold, you probably won't notice it.

 

[rimmbrme]

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wiring diagram

 

[NeMiZiS]

Thanks for the diagram.
But I was working on her last night and I was trying to figure out why it wasn't running right.
Then I noticed that the person I got it from put the spark plugs in the wrong order!
I fixed them started it up and then the tach was working!
Any one else ever heard of that?
Then it ran out of gas,or at least I hope it did.