Intermittent, but frequent, jumpy tach past 5K or so
07-26-2012, 01:50 AM
#1
Three Wheelin'
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Location: Colorado Springs, CO USA
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Intermittent, but frequent, jumpy tach past 5K or so
Anyone else seen this on a digital dash. Often, when the tach gets past 5K or so, the needle will start jumping wildly - like +/- 500RPM. Sometimes it will stay smooth through 5K and up, but most of the time it will start jumping. Below 5K is always reads well, with no jumping at all. I don't notice anything odd from the engine itself in this range; it revs smoothly right through the area where the tach wigs out.
The car has a Sharktune it, BTW, but I spoke with Jim, and he didn't see that that would have any effect on the tach if it's not affecting the ignition itself.
I'm thinking I'll probably need to feed a sample signal into the tach from a function generator, and/or scope out the EZK feed to the tach, to see whether it's a bad signal or a bad tach, but I just thought I'd ask in case this was an issue someone else had seen (and preferably solved) in the past.
Thanks,
Paul
The car has a Sharktune it, BTW, but I spoke with Jim, and he didn't see that that would have any effect on the tach if it's not affecting the ignition itself.
I'm thinking I'll probably need to feed a sample signal into the tach from a function generator, and/or scope out the EZK feed to the tach, to see whether it's a bad signal or a bad tach, but I just thought I'd ask in case this was an issue someone else had seen (and preferably solved) in the past.
Thanks,
Paul
07-26-2012, 02:07 AM
#2
Archive Gatekeeper
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Rennlist Member
No idea what you're talking about. 
Sometimes I get a jumpy tach in the immediate moment after the key is turned to the start position, I always assumed it was some sort of voltage spike-y event as the car comes to life. But the tach needle is steady whenever she's running.
Now my temp gauge, that's a different story:
Sometimes I get a jumpy tach in the immediate moment after the key is turned to the start position, I always assumed it was some sort of voltage spike-y event as the car comes to life. But the tach needle is steady whenever she's running.
Now my temp gauge, that's a different story:
07-26-2012, 11:24 AM
#4
Rennlist Member
My gauge are all steady (stock ignintion) I assume that your pod was out when you replaced dash (and did the same problem occur prior to this project) are all the connector locked-on and dash related grounds OK?
