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Discussion Starter · #1 ·
I have a little sunpro tach I bought for my Geo and never hooked up, I was thinking yesterday since I redid my gauges that my tach is wrong, that I could hook it up my little tach up so that I can see actual engine speed and adjust my in-cabin tachometer accordingly?

I'd read the instructions, but it's been over 2 years so I don't think I would be able to find them if I could. :wink:

Thanks
 

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The best way to re-do the tach is actually to get a stock gauge cluster and then pop out that little plastic nubby that the needle rests on when the car is off. The needle will then fall past the nubby and settle out. Take a pic of it, and then take out the nubby for the tach in your car. Adjust the needle until it hangs in the same place and you should be golden.

Taking the nubby out won't do anything to the accuracy of the gauges. Taking the needle off the spindle of course will.

Or what you can also do is take the tach of a junkyard car or something and just use that one instead.

The only thing about splicing into the signal wire of the tach and splitting it to two tachs is that you will increase the resistance and you can alter the reading. Chances are it will be neglegible, but keep it in mind.
 

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Discussion Starter · #3 ·
I know what you mean with the nubby thing, but hte problem is I didn't have a camera to do that with when i redid the gauges, so I know I'm within 300 rpm but I don't know if that's +300 or -300 from what the tach says, I tend to wind my car out, so that gets a bit iffy for me.

Short of having to pay to have it professionally done, is there a way I can re-align my tach?

My temp, gas and speedo are also all slightly off, but I know once I get my tach done I can adjust my speedo accordingly because I know what speed occurs at what RPM. (i.e.: 40 mph is @ 2900 rpm in 3rd gear & 50 mph is @ 2900 rpm in 4th gear)
 

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just slap the sunpro on real quick..

should be 4 wires -

black - ground
red - power
white - lights (not needed)
and the last one (usually green) goes to the negative side of the coil..

don't even have to put it in the car, just hook it up in the engine bay so you can see it from in the car..

or take the needle off, floor it till the rev limiter kicks in, and hold it there while you put the needle at 7200.... jokes.
 

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Discussion Starter · #5 ·
Yeah 4 wires. I even have a pic of em incase someone asked :D

Where would I go about putting the red wire to? and the negative side of the coil is where exactly? I have an idea of where it is, but i'm not 100% sure. The ground I know of for a fact :wink:



It's sooo cute. :p
 

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black/white/red/and ?

black - ground
white - not needed
red - hook this to any positive wire that has power running through it while the car is on.. (i usually shove it underneath one of the fuses in the fuse box)
and the last wire, you'll probably need to check in your chiltons/haynes to figure that out.. i don't have one, so i'm not sure. i'm sure someone on here knows.. SIRAGAN?
 
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