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.

 

[Kalub]

What is the best way to get axcess to the intake manifold stay that the noise filter is mounted to? Can you axcess it from the bottom of the car?

 

[1990AWD]

What is the best way to get axcess to the intake manifold stay that the noise filter is mounted to? Can you axcess it from the bottom of the car?

no I don't think so. I think the only way you could get at it is reaching from on top or removing the intake manifold

 

[Kalub]

Ok so today it was a little nice outside and I decided to look around in the car some more. I jammed my arm up under the intake manifold stay and clearly felt the noise filter, so I decided I would move my throttle cables and attempt to remove the fuel rail and get to the coils.

No Bueno. My lame Walmart toolkit didn't have a 12


So while I was looking around down under the fuel rail I noticed a puddle of oil. Curiously I looked at my dipstick and noticed black electrical tape on it. So I called the previous owner and he said it had shot the dipstick under boost and sprayed oil everywhere in the bay. He took it to a car wash and pressure washed the bay. He said that's when the tach stopped working. So I jammed my arm back up under there to feel the noise filter again and sure enough it is all oily, not to mention the puddle of oil and oil all over my coil pack.


Just curious, but could pressure washing the engine like that ruin the noise filter or tacho-interface? Until I get a 12mm end wrench or socket I'm on halt to removing my fuel rail to check the coils. Is there a methodic approach to this madness? I'd really like to hook a multimeter to the ecu pin that controls the tach and see what is being displayed there. Anyone know what I should find?

Either way, if the tacho interface is toast due to it getting wet, what should I do? Are they easy to come by? Or what.

Here, I got the fuel rail off, and here are some pics of the puddles that I cleaned up and the tacho interfae. It's pretty nasty under there.

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[1990AWD]

well its a good thing you found the noise filter and its there. did you make sure it was plugged in? I would still take out the coil pack and clean everything you can. I have no idea if the tacho interface is easy to replace/find but you could always find a coil pack of a wrecked dsm easily

 

[Kalub]

When I had the fuel rail out I couldn't see a way to get the coils out without completely removing the I-mani. And as far as I could tell I found the plug on the end of the pigtail harness (Two wires, a white and black pair) and followed it back to what felt like a small rectangle peice of metal screwed to something. I can't really tell if it is functioning properly though.


So I'll take the fuel rail off another day and try again. Till then I need to figure out how to test these devices electronically to see if they are working. Say I was to hook a meter up to the tach-interface, which wire would I use and what would I expect to see? And then I can test the noise filter, and then the ECU pin. Then I can determine where the fault is.


Anyways, let's keep this thread going, so far it seems to be a pretty good place for collective information on the subject. (Least the most collected thread I've seen with the most details)


And any more insight/advice to some of the questions present in the thread are very much appreciated.

 

[RedEyeBanDiT]

Does anyone know if a 1990 cluster will work in a 93' and if not what are the differences in the clusters ?

 

[tsi1991awd]

Glad I came across this thread because one, I have a 1990. And two, my tach doesn't work either. I have to look down at my SAFC to see what my RPM is.

Mitsu STILL makes the part, it is part number MB542494. This can be cross referenced even in the 2g. It is used for the antenna as well, so I may just take a peek in the back of the car since I never use the radio, and see if there is one back there. If so, it's worth a shot.

 

[adollarwodbnice]

So this same exact part that controls something on the antenna too???

 

[Kalub]

Wow forgot about this, anyways I took the car to Satan. They repaired a white wire if I recall correctly coming off of the crank sensor? Ill get pics if you folks want them.

 

[tsi1991awd]

So this same exact part that controls something on the antenna too???

It is a noise filter, reduces RFI....there is one somewhere in the antenna wiring for the car.

 

[G-zuz]

Does anyone know if a 1990 cluster will work in a 93' and if not what are the differences in the clusters ?

I have a similar problem as this guy only mine is a 1990 TSI AWD with a 1993-1994 computer (6/93-5/94 - MD304484 E2T60879 EB21) and have heard that a 1990 tachometer won't work with differing years or specific ones. Does the 1990 cluster work or does it have to be a 1993-94 cluster to work with this ECU?

 

[obsidian]

http://www.dsmtuners.com/forums/articles-electrical-wiring/414636-how-fix-1990-dsm-tach.html

You're all welcome.

90's use 90 ecus and 90 gauge clusters.

if you mix a 90 part with ANY other part, it won't work.

A 90 turbo gauge cluster goes up by 5's. 5, 15, 25, 35, 45, 55....

91-94 went up by 10's 10, 20, 30, 40, 50

 

[Eclipse2630]

my buddy had this problem and it was that plug in the picture. worked perfect afterwards

 

[sk8freak8989]

I also have that connector jumped like that. I have heard some people say it can damage things, but i have had mine like that for more than a year and it is still woring fine.

 

[obsidian]

You're actually the guy who got me to just try the damn thing and then post up the how to.

 

[G-zuz]

http://www.dsmtuners.com/forums/articles-electrical-wiring/414636-how-fix-1990-dsm-tach.html

You're all welcome.

90's use 90 ecus and 90 gauge clusters.

if you mix a 90 part with ANY other part, it won't work.

A 90 turbo gauge cluster goes up by 5's. 5, 15, 25, 35, 45, 55....

91-94 went up by 10's 10, 20, 30, 40, 50

Thanks alot, man.