captcashew

All-
I hate to post this since I've done some searching and everyone posts this. But I've been having trouble with my tachometer and speedometer lately and my fix came up empty. The short story:

Last year or two, my speedo has been intermittent. Slowly being more off than on until this past fall it was mostly off. Not a huge deal until I was on a PCA drive and realized I really rely on knowing how fast I'm going if I'm pushing things at all. So, I figured I pop the instrument pod out, clean some contacts and be good. I've done it about 4 years ago and followed the write up on Dwayne's Garage, so I figured no sweat.

Also, in the last year, the tach stopped working too. Nothing intermittent about it. Just stopped. But I figured it was something similar and when I took out the pod, it would fix that too.

Well, I just got done putting everything back in. I even took off the PCB on the back of the instrument cluster and cleaned everything. But honestly, things looked pretty good. I didn't do any of the soldering like Dwayne did for his speedo because it all looked good. But when I popped it all back in and started it up, no tach. I couldn't really take it for a drive or even move it to check the speedo, but since the tach fix didn't take, I thought I would post here before I button everything up all the way. Most of the pod is still taken apart, I just connected it all up.

Does anyone have any suggestions? Are there certain fuses or relays that could be the issue? Could it be a ground that needs cleaning? I did clean the grounds not that long ago and probably pretty shortly before the initial issues with the speedo, so I wouldn't think that. Is there some way that I could bench test it to see if the issue is with the cluster? Any help is appreciated, as always.

Thanks

-Bill

soontobered84

From the tiny picture on your avatar, I'm just guessing that your car is an 87 or 88 S4?

We would like to help you or at least help guide you in the right direction, but without knowing the year, it would be hard to nail down a specific cause or solution because different years have different issues.

In addition, please tell us what you mean when you say you cleaned everything. What was used to clean it?

Are you sure you attached the wire harnesses in the back of the pod the exact way they came off?

captcashew

Dang, I know I replied to this a couple weeks ago, but looks like my reply didn't show. Yes, it is a 1987 S4 Auto.

For cleaning, I basically cleaned every metal surface with electronics cleaner. Nothing really looked that corroded. I pulled the PCB off the main plastic housing and got the back too. I did the metal rods that were pulled out from what I think was the speedo and cleaned those too. Everything went back together fine, nothing pinched or anything like that. I also used stabilant 22 after everything was clean and dry. I cleaned the connections that were in the car too, although that was just with q-tips, so they weren't scrubbed quit as well.

I double checked and I'm pretty sure the 4 connections in the car went to the right slots on the board. I figured those wouldn't be interchangeable though. But since the issue started long after the last time I was in the pod, I didn't check that closely when the other things were working fine. But I cna double check.

Any help is appreciated.

Thanks

-Bill

Wisconsin Joe

Well, first off, the rivets on the board can look fine and still not be getting good contact. Did you put a meter on them to see if you were getting continuity?

Second, if both the speedo & tach are dead, then it's likely a connection in the pod. They get their signals from different places.

Last, although it's a bit sketchy, you can drive the car a bit with the pod out.
I did my speedo (soldered the rivets) and put everything back together, only to find that the "fix" hadn't worked.

So when I "refixed" it I made sure I had continuity through the rivets with a meter, then put the cluster in (no pod) and moved the car up and down my driveway to see if the speedo would twitch. It did, so then I put everything back together.

captcashew

Yeah, I guess the main thing I really didn't do when following the Dwayne's Garage article is working on the rivets. Looks like I'll have to monkey with that to make sure. Oh, well. It's strange that the speedo is very intermittent. It seems to work more often the warmer it is outside. The tach is just nothing.

I was hoping to tackle it during the winter when I wouldn't be driving it as much, but maybe I will have to wait until I can drive it around while working on it.

Wisconsin Joe

Intermittent speedo, works better when it's warm is exactly what mine did.

After the first attempt failed, I put a meter on the rivets to the pins (I think). No continuity, but I could get 'flashes' wiggling it around.
After resoldering it, I had good continuity, even when wiggling it.

captcashew

OK, well I guess it is time for me to resolder the rivets. Thanks. Sounds like that is the step to take.

Does anyone have any ideas on the tach?

captcashew

Thought I would bump this up to see if anyone has any suggestions on a non functioning tachometer. I've cleaned all connections on the instrument cluster, pcb and the connections inside the car.

Oilystair

I know this thread is getting on a bit but did you actually sort out this problem in the end and if so what was it ? I’ve just attempted to fix the rivets on my one and got a bit carried away, tried to ‘mend’ some of the stuff that wasn’t actually broken and messed up the PCB foil with the liquid metal wire glue, it was going great but didn’t know where to stop. Big lesson learned there and am having to most likely look at a new PCB fool when I can actually find one. Just wondering if you solved your problem.