TACH Problems

[00 Agent]

I'm having problems with my tach. Sometimes it works, sometimes it's stuck at 0, most of the time it just wiggs out and jumps around. My S-AFC still shows the correct RPMs. What could be the problem?

 

[honduraneclipse]

under your intake manifold there is a braket with vaccuum hoses attached to it ... look at wire/plug on top of it to see if it came loose or its just dirty

 

[LightningGSX]

If your AFC still shows correct RPM, its probably in the cluster.Take out the cluster and on the back ,make sure the connection screws are tight.

 

[00 Agent]

Check and check...tach still doesn't work. I guess it's safe to assume I need a new cluster.

 

[mikestalon96]

i purchased a new cluster to fix the same problem and it didnt work...somewhere below or near your manifold there is a plug... Make sure the connection is tight and or clean... i suggest looking in a chilton first before you go pulling random plugs to find the correct one.


...I am also willing to sell a cluster...its used but working and in good condition with 128000 on the speedometer

 

[00 Agent]

I checked the plug and it seems fine. What's a good thing to use to clean it?

I'm probably going to end up buying an external tach.

 

[Oliver]

Do you have an Aftermarket Gauge face?
If you do, the problem could be the needle getting stuck on it...

Mine used to get stuck on zero and it took just a lil tap on the panel and it would work fine again.... but I've already fixed this!

Sounds lame but if you do have an aftermarket gauge face, it's an alternative

 

[LightningGSX]

You can just replace the tach and not the whole cluster.Shouldn't be that hard to find, if you can't find one, I have two spare clusters.

 

[honduraneclipse]

i forgot to mention that the only reason the tach on the SAFC is working because it is tapping the signal straight from the ecu inside the car... the engine bay one is the factory tap

 

[laserblue]

Info...
1990s use a different tach 'buffer' than '91s on so be sure to get the right one for your year.
Here's a pix that might[?] help. [note the red circle]
http://www.dsmtuners.com/forums/showthread.php?postid=453875#post453875

 

[00 Agent]

Thanks for all the help guys, I just went ahead and ordered a 4" tach with a shift light. Been planning to do that anyway.

(and if you think that's rice you can kiss my ass)

 

[Oliver]

I just hope the same thing doesn't happen with the new tach

 

[00 Agent]

Originally posted by Oliver
I just hope the same thing doesn't happen with the new tach

It does. It's tapped to ECU pin 109 I believe (tach signal). I have verified that the noise filter is not the problem. What else can I check?

 

[00 Agent]

Come on, someone has to know what I can check. I'm at my wit's end here. If I had hair I would be pulling it out.

 

[honduraneclipse]

try to switch with a ecu that is working with the tach and then go from there

 

[00 Agent]

Well just to let everyone know I replaced my coil pack and the TACH(s) WORK!