Thread: P10 jumpy Tachometer

I am working on a P10 that has an intermittent issue with the tach bouncing and jumping erradically.
Anyone has any insight on this?
With the key on not running it does this and also while running??
Totally random.It will be fine for awhile,then goes berserk all of the sudden.

crazy-tach... pretty sure we've all had it (p10 owners that is). I have always just replaced my clusters to rectify the situation, I think it is in the gauge itself. If you take a look around on Gnet, I think there may be a thread about the actual cause.

Fairly common late 80's early 90's Nissan problem. The wife's old '89 240sx suffered the same problem, had to replace the cluster twice as the first junkyard cluster had the same issue.

i dont know if the p10 uses the same tach as b13, but ive taken my cluster apart and have replaced the tach drive motor before from a b14. simple swap of the motor and needle. 3 screws once you get the cluster out and apart.

Ya my B14 does this same thing. Once I hit ~3100 RPM, it goes wonky and is inaccurate above that number.

hmmm oddly enough mine is pretty accurate. did you guys compare to what the ecu is saying, an external tach, then adjust the tach itself? iirc there is a trim screw to do this with. the screw wont fix the buggyness, but will fix the inaccuracy.

i posted a fix on g20.net.. that works for the maxima guys...

i havent tried it YET on my p10, since im still so far away from completing the car

I used the sAFC II that is wired into the harness for the RPM value reference. It was pretty close until the needle went jumpy. Under 3100 RPM, accurate. Over ~3800 RPM, inaccurate. In between those values, the needle goes wonky.

link? I know about the maximas having that issue,but was unaware of the p10

Fix = Monster tach and some decking screws.