Weird tach: different sensitivity

[keruhas184]

Hello all,

I wouldn't really call this a problem, just a weird, maybe a bit annoying thing.

Some days my tach would show (what I think) proper rpms - i'm yet to go beyond 4500 in that mode (engine gets kinda loud then, and clutch is pretty much adios)

Then some days the tach would become real sensitive, and would show me shifting at like 6000! It doesn't go to 6000 rpm at 35mph in 2nd, unless my engine is totaly wack', but it runs OK for 230k. The car behaves the same no matter what the tach decides to show.

The tach mode of the day usually gets set when I start the car. Before I installed my MSD coil it would switch at high loads between sensitivity (like when doing 80 for 20 min)

So, I pretty much have the whole ignition works: new dizzy, wires, plugs, coil. And I can't see a real correlation between this mode switching and weather or temp...

Is this just a bad tach sensor? Or should I be worrying about this and be replacing something?

thanks a bunch

[dXsquared]

get an aftermarketach..only like 25-30bucks for a basic one..and they are usually very acurate

Travis

[keruhas184]

Um.. yeah. After working properly all summer, my tach got wild again. I'm thinking it maybe has something to do with the carb... The car sat a week in the parking lot, and now 2k became 4k. Overall engine still feels the same...

I'm not really going to replace the tach, I just want to know why it does this... How can it work fine and then switch like that? Anyone have any idea or experiencing the same problem?

['89AccordLX(Rus)]

Since the tach runs off of the coil signal, your coil may be causing a problem or your distributor is making it act up. Check the distributor for signs of wear (ie red dust in the cap, noises, etc.) Make sure the connections to the coil are solid and well insulated too.

[keruhas184]

Hmm... the coil and dizzy are new... It rained today and i opened the hood to add some oil... some water did drip inside... I guess I'll insulate the coil wires better... thanks .

[Jareds 89 LX-i]

My dad had this exact same problem with his SE-i not long ago. Every once in awile it would work perfectly fine, but most of the time it read way higher than normal, and would show it shifting at 5000-6000 rpm during normal easy driving, LOL. Tried switching the coils and dizzy with mine, no change. Changed the tach itself (the actual guage in the cluster), has worked perfect ever since.

[keruhas184]

Alright, good to know that it might be just the guage. But I'll probably be keeping mine. Its nice seeing the needle on 8k right before you shift, in a weird sort of way...