Recently my '91 LS400 has been experiencing a tach problem that is slightly different than those that I've read about in these forums. On start-up the needle jumps to 500rpm and just stays there regardless of what the actual engine speed is. Before this problem occurred, I was having some intermittent problems with the tach just sitting at zero for a short time after starting (twenty seconds or less). Any ideas?

Thanks.

 

Its probably because of lube in the needle mechanism getting old and sticky. Does it work better when warm? May need to relube...

 

Can you tell me how to lube the tach? Is there a port of some sort to introduce lube (I've never had this instrument panel out, let alone the tach), and what type of lube would be required?

Thanks.

 

I have never done it personally. Probably have to remove instrument cluster and somehow get to the mechanism. There is a DIY somewhere. Mine does the same thing but i don't worry about it...

 

http://www.lexls.com/tutorials/elect...ntcluster.html
http://www.lexls.com/tutorials/elect...sassembly.html

 

Old thread, I know.
Anyone else have this problem?
My '91 was acting like this the other day up in Tahoe where it was ~35 degrees. First I noticed it stuck at 0. Later it was stuck at 800. Later I noticed the stick point could change. Seemed just like a purely mechanical sticking somewhere. Due to its appearance when it got cold, I assumed it was cold related.
Now that I'm back in a warmer climate, everything is fine again.
I'm inclined to do nothing at all on this until I'm sure what's going on.

So, does anyone have similar issues, or quick repair suggestions?

 

Needle/motor assembly is going out. It will eventually fail. We can help, give us a call.

 

This Post helped immensely! I was able to see how the cluster came out of the dash. I also viewed pics on the entire cluster. And I listened to a video about sticking gauges. Unfortunately, the LS400 was not a cluster the video add company would repair. A further post by Tanin Auto Electronix and link to their website is a place I will consider to send my cluster for repair. However, and e-mail is required for them to ascertain the full cost of the repair before submitting the item to them to fix. I hope I'm not following a pipe dream.

 

I read a post that said oil needs to be applied to the dials. However, that post could not say how or where to do that on the cluster. Your little quip about the needle/motor assembly going bad makes more sense to me. Thanks for the website link. We shall be talking soon,