Hey guys, my first post after purchasing my first British car.

Basically, the tachometer doesn't work all the time. If I unplug the battery, it will reset to 0, and work fine for about 50-100 miles before it starts to indicate randomly, or not move at all. For example if i'm idling, it will 'idle' at 3200 rpm, and work fine as if it's calibrated that idle is 3200 rpm, then a few miles later decide to 'idle' at 6,000 rpm and if i rev it up, it goes off the scale. All other gauges work perfectly and accurately, including trouble lights.

Car is 2003 2.5 manual base model; no computer, just miles driven and trip meter.

 

I really have no idea what's going on here and I don't think anyone has seen anything like this before. It might be wiring, or it might be your physical gauge cluster (my bet.) I say the gauge cluster because if it at some point resets to what it should be, that's probably mechanical and not electrical. Disconnecting the battery simply pulls the shaft of the tach back to the original point, but I think that the screw on the tach needle is not fully attached to the tach shaft. I would buy an extra cluster from a junkyard (pretty cheap) and test it out. You will have to remove the dash which isn't too hard. If you want to do this and need a second set of eyes, just post pictures as you go and I will help you out!

 

I agree with disguay in that it is most likely a mechanical problem related to the gauge cluster. I hope you figure it out and keep us updated on your progress!

 

Surfer, you are having a failure of your instrument cluster. Unfortunately, the fix is having to get a new instrument cluster. There is the option of sending the instrument cluster out to a repair place and they will replace the chips/components necessary to make it work again. But, while the cluster is out, the car will not be driveable.

 

Hey CalI, this is Roc here in dirty Jersey East Coast I was reading your post so I had a bit of an issue with my RPM tachometer it would drop to zero it would move slowly it would freeze i would knock on it and it would work fine for about 2 minutes so I decided before buying a new one that I would take the tachometer out and see if there was a way that I could get to the PIN and on a 2006 Jag xj8l which is what I got I was able to do some you take off the woodwork you unscrew the four screws for the plastic cover then you unscrew the other four screws for the for the cluster box you pull it out very gently and then you should see for Clips on the back that you just lift up with your fingers and the glass cover should pop off. now what I did was I did a little scientific experiment and put a little WD-40 in the space between the pin and the backboard where the where It could go in a little bit in the hole.and I did that and I put everything back together. I suppose there could be dust in there after 13 years you know I'll dust gets in everywhere even though it's covered you even clean the whole tachometer and the glass cover so then I started the car and it's been good for about 50 miles now by now it would have already been getting stuck down or dropping to zero and not working at all so I conquered the issue I'm pretty much under the impression of because it would have already been down to zero as I said getting stuck the other gauges are fine so you could try that out get back to me let me know how you made out if you didn't already changed the whole tachometer.. Roc 212 390 8704 # if u wanna call I do as much work on my car's I have an old one as well as possible because I don't want to spend money that's unnecessary I'd rather learn and fix things myself as long as it doesn't have to do with the engine in too far involved I will also do work on that as well like pressure sensor the mass air flow sensor gas pressure sensor things of that nature I'll take care of myself

 

Good luck. The original poster hasn't logged on here in 7 years and I would think by now, if he even still has the car, he would have addressed the issue. Plus, this is the X-Type forum. You have an XJ. Not sure how much of the information would translate to a X-Type.

 

Ay no prob didn't check out the post a I was just reading what was written although at least other people can get the information and could possibly be helpful to you others if in a similar situation thank you for your response