Tachometer Isn't working

[Kalub]

Hello


My tachometer in my 90 TsiAWD is not working, is there any way to trouble shoot it?

Can I hook up a multimeter to the plug the guage plugs into and see if it's working right and then work my way back to the coil/noise cylinder thing?

Oh, and I did try a new guage cluster, there are some differences between mine and the new one.

Mine's speedo counts like this: 5/15/25/35, the new one counts like this: 10/20/30/40
Mine doesn't have an Anti-lock light and this new one does. After talking to the guy I bought it from he said it came out of his 90 Awd Tsi and it should work. So here I am.


Any help is appreciated.

 

[1990AWD]

I'm not sure on how to fix it but its located on top of the transmission. When you find out, tell me b/c mine doesn't work on my '90 TSi FWD and I don't want to start ripping things apart without knowing anything about it

 

[Hcaruso4]

make sure all the connections are solid especially grounds

 

[4G63_Attack]

Have you change your ECU ??

 

[Kalub]

No, the car is bone stock, and I guess the sender is actually on the coil pack, and then it runs to a noise transistor on the intake manifold, then to the tach/ecu.

 

[awd4g63turbo]

Check the noise filter. It is located on the back of the intake manifold and looks like a metal rectangle with a couple wires running to it. If it is not plugged in your tach will not work. If its not that take out your coil pack. There will be a black plastic peice with 3 wires running to it. It is called the "tacho interface" if all the wires dont have a good connection the tach will not work either. Ask me how I know all this,
Also all the 90 speedometers had 5,15,25,35, all the 91-94 had 10,20,30,40 so that is what I would start changing first.

 

[stevestevesteve]

just take it to an electronics shop. my buddy took his DSM to a car stereo shop becuase his tach wasnt working and they fixed it for 25$ it was a faulty wiring problem

 

[Detective Coating]

I agree with awd4G63turbo. I can almost guarantee that it is your noise filter. It is a very common problems on 1990's.

 

[Kalub]

Not to be a problem maker, but can any of you guys take a quick picture of what I'm looking for, or locate it here


That would make my day. Still, can I just hook a multi meter to a few of the pins on the plug the guage plugs into and see what's up?

 

[Detective Coating]

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[Kalub]

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Is this the noise filter? Any way to check if it's kosher?


edit: didn't see the post above mine, let me go see if I have that somewhere.

 

[Detective Coating]

What you have pictured is your ISC, other side of the IM

 

[Kalub]

I can only find one plug that is tiny like that, that has white and black wires coming from it. It's tucked way under there and I ca't see where is goes, or what it is hooked to.

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Can't I just hook a multimeter up to the plug the guage acutally plugs into (the square one behind the clutser) and test if anything is happening back there? I'd like to test the connections/electronics before I go tearing around. (I'd be a cranky mofo if I got that plug in this last pic all pulled out and it was fine)

 

[1990AWD]

No, the car is bone stock, and I guess the sender is actually on the coil pack, and then it runs to a noise transistor on the intake manifold, then to the tach/ecu.

sweet deal I'll have to check that on mine tomorrow

 

[Kalub]

Good luck man, take pics if you can find anything because I'm still running dark. I can't find anything

 

[1990AWD]

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I think I found the conecction for what you have pictured but its not hooked up to anything. I found it behind the IM wrapped up with a bunch of other wires. I found another conncetion that looks like its the same but its plugged in with something else by the brake/clutch resivoirs. I also found a couple other plug/connection things that aren't plugged into anything. Does the fact my engine is from a '93 and the car is a '90 that there are so many loose connections? I'll try to steal my sister's camera and take pics later today.

 

[Kalub]

Could be, the 90 dsm is electrically a different animal than the rest of the 1g's (91-94). And it's been kinda a problem because of that.


If only someone knew which pins on the gauge plug I could tap into and see if the electrical values were changing when the motor rev'd etc. I don't think it's anything but the gauge cluster itself because sometimes the needle likes to come alive for split seconds.

However, I tried a cluster from a 91 awd and it didn't work. Who knows.

 

[1990AWD]

Kalub, I went and looked for it on my other '90 Talon that I have the head and intake manifold and all that junk off of and the noise filter is bolted to the underside of the intake manifold stay. its connects into a plug that is part of the bunch of wires that run along the fuel rail and then behind the intake manifold. I'll get pics of it tonight when my sister comes home with her camera.

Another thing, on my other Talon which has a motor from a '93, I looked for it and found out that the intake manifold stay in non-existant (I bought the car when I was a total noob and had no idea what to look for under the hood of a dsm haha). Because the stay isn't there I have no idea where a noise filter is for it. Does anyone know about this on a 7 bolt? The tach still works if the engine is wet but then stops working.

 

[Kalub]

Hey thanks man, and that's funny that the tach works when the motor is wet. Mine tried to work when I drive. It just occasionally, and randomly jumps to 2k then fails again. So I thought it was the cluster, but who knows. I'm just gonna hook a meter up to it when I get the chance and see what I can find, or blow up.


I'll be waitin' anxiously for those pics. Thanks again

 

[Talon2139]

Hmm. I had the same kind of problem, but it was because someone had swapped the engine harness from a 1gb into my '90 tsi. We eventually just swapped the body harness and gauge cluster over as well, and that solved the problem. We had to swap out the gauge cluster with a couple of different ones, but eventually found the correct combination, or right mix of actually functioning pieces. Thank God for spare parts!! I thought there was a spot to test the base timing that also had something to do with the tachometer signal tho.

 

[Talon2139]

Okay, heres a couple of engine bay pics, hope these help. The arrow on the left is pointing at a plug, where i think u can supposedly hook up an external tach? and the plug on the right is where you set your base timing.

 

[Kalub]

1990AWD did you get the pictures?

 

[1990AWD]

1990AWD did you get the pictures?

I will as soon as I can get them on the computer. stupid camera...

 

[1990AWD]

Kalub, do you know how to get photos that are larger than 700 pixels onto here?? If I crop my pics down to under 700 pixels, you can't see anything worth a damn

 

[Kalub]

I use imageshack because they resize it for you if you tell them to