RPM tach is going crazy
 

gotta a question about a lil problem with my car and the tach for the rpms---
at about 3000 and on the needle for the rpms start going up and down not at all with how the rpms really are

and if im like buckin downt he road the rpms are all over the place so if anyone can give me a lil info on what to check when i get back home since im in chile right now haha

RE: RPM tach is going crazy
 

Year and model? V6 maybe?

RE: RPM tach is going crazy
 

get a new guage cluster, most likely your tach went bad...f

RE: RPM tach is going crazy
 

First, are the car's RPMs actually jumping around or does the car drive (and most importantly shift) normally when this occurs? If it does then there's a possibility it could be your shift solenoids. I had some go bad on a Camry one time and the tranny was actually jumping around and not shifting correctly. The reason I ask this is because you used the phrase "buckin down the road", which would accurately describe what that Camry did when the solenoids went bad.

If the RPM gauge appears to be "doing its own thing" and the car drives normally, then it very well could be the gauge cluster. But, it could also be a bad connection at the battery terminal (due to corrosion), a bad battery, or a failing alternator. The gauges in my '96 Accord went completely crazy when my alternator went bad. The tach jumped around and so did the speedometer... until finally they both just dropped to zero. The ABS light and battery light also came on too, so take a close look at your other gauges when this happens and see if anything else looks fishy... if it does the electrical problem could lie elsewhere (than the cluster).

RE: RPM tach is going crazy
 

My brother's Legend does that.....his is the gauge cluster. There were several of his model built with a defective gauge cluster. It will work fine at times, then just go crazy. Usually just the tachometer, although on occasion the brake lamp indicator and oil lite will come on. His speedo is mechnical, so it works fine all the time.

Strange as it may seem, he can temporarily make his work by striking the dash right above the cluster. Everything usually goes back to normal for a while. You might try this, just don't break your car in the process.

RE: RPM tach is going crazy
 

pop the hood and look at the front right hand side of the vehicle next to the firewall. There will be a little blue connector with two wires going to it. This is the manual connector for a tachometer. Get a manual tach and plug it in there, if it jumps around I'd start looking at sensors, if it runs normally then I'd say cluster. That's about the cheapest option for diagnoses... just buy a manual tach from an auto store then take it back and say it doesn't fit your connector type... or borrow one from them or rent one from a mechanic....

RE: RPM tach is going crazy
 

The tach on my 1997 Honda Accord EX V6/160,000 miles would not work at all or would jump around. Car ran fine. Read on this forum or possibly another that on V6's the tach gets it's signal from the ignition coil, on 4 cylinder models from the ECM. I replaced the ignition coil on my V6 and the tach works fine now. What I had read was that the coil can begin breaking down just enough to effect the signal to the tach but not cause a problem with ignition, at least in the beginning. I'm sure eventually the coil would get so bad the car's performance would be affected.