Tachometer Problem

[rotaryconnection]

I purchased an 81 RX7 six years ago from the original owner. He had been very good about upkeep and included a shop manual and a most/all of the invoices related to the repairs and adjustments that had been done over the years, usually by Mazda dealerships. New seals had even been installed in the engine. Overall the car looks and runs great and I couldn't be happier.

Recently, however, the tachometer has started to malfunction. Sometimes it works and other times it doesn't. Would the problem most likely be in the tachometer itself or in another related part found elsewhere on the car? The shop manual indicates that the instrument cluster or "combination meter assembly" can be removed from the dash. If the problem most likely resides within the tachometer would the best solution be to replace the entire assembly assuming that one can be found?

[lawnronger]

just had a problem like yours on my 83 gsl. the trailing ignitor was bad on the dist. car will run without the trailing ignitor but the tach won't. they're on the outside of the dist. they're j-109's. the trailing is the one closest to the alternator( the harder one to reach) i got a used one on ebay for $30.00. i'm no mech it's a easy fix- remove the two screws put the electric grease on the replacement plug the wires back on you're done.

[rotaryconnection]

Thanks. Your suggestion was very close but the problem turned out to be a (sometimes) slipping alternator belt. Unfortunately, the slipping belt also polished the alternator pulley which worsened things. Apparently, that doesn't take long at five or six thousand RPMs. I learned the hard way to regularly check the belts for tightness.

[83ROTRY]

Sorry I don't have a suggestion for fixing your tach, other than perhaps to compare notes. I recently picked up an 83, excellent condition, only 54K miles. Runs great. However when it is just started, the tach is very 'sticky' -- stays low and slow even with engine revving, but eventually climbs some. Then when engine is idle, sticks at the higher level, but eventually comes down. Once the engine is fully warmed up though, the tach appears to work fine. Does this sound like what yours does?

Has anyone else seen this? Is there an easy fix? Is this a problem (meaning, if I just leave it, is this behavior hard on it and will cause the tach to completely fail?).

[rotaryconnection]

It does sound a little like my former problem although mine didn't stick, it worked intermittently. Check the belt for looseness and/or use some CRC Belt Conditioner and see if that improves matters. Even slightest slipping causes the tachometer to go nuts. Also, have an auto parts store test the alternator. If those measures don't help I would suspect the instrument. Right off hand I don't know of anyone who works on delicate gauges and finding a replacement may be nearly impossible. At one point in time I even considered replacing the entire instrument cluster (which is fairly easy to remove once the steering wheel is pulled off) but there are none to be had for love or money.

[83ROTRY]

Ok thanks. Don't think its the alternator, would be other signs I suspect. But I will check the belt when I next go work on it (it's still a little cold up here for a few more weeks, I don't run that old rotary in the winter).

[rotaryconnection]

If it wasn't you please disregard this post. I bought a set for my 81 through J.C. Whitney. They fit and work perfectly and didn't require adapters. Couldn't be happier.

[rotorlife]

Thanks, your tips should help solve the problem.