Crazy Tach
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Joined: Mar 2005
Posts: 68
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From: Plantation 1990 L98 383 Stroker Florida
Crazy Tach
I am a new owner of my first vette a 90 coupe. Everything works fine except the tach. When the car is started the tach jumps to 6000 RPM and then falls down to zero where it does not move again. The coil has been replaced with one of those excel high performance coils. Could it be the ground at the coil if so how do I identify it?
Race Director
Joined: Jul 2004
Posts: 16,795
Likes: 62
From: Lake Havasu City, AZ
It might be a ground problem. I don't know how to conclusively prove that, but you could try removing the coil wires and re attaching. is possible the pins did not make good contact the first time.
You might have the wrong Accel Coil...
They specify red and white wire or red and yellow wire.
Do you still have the old coil and do the wire colors match what is in it now?
Another possiblity I've heard is that your Tach filter is shot. Perhaps someone can tell you how to check and where to find a replacement.
You might have the wrong Accel Coil...
They specify red and white wire or red and yellow wire.
Do you still have the old coil and do the wire colors match what is in it now?
Another possiblity I've heard is that your Tach filter is shot. Perhaps someone can tell you how to check and where to find a replacement.
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Even if you will fix this crazy situation you will end with an incorrect reading.
90 tach s are wellknow to be without accuracy.
My stock tach was off even 1500/1800 rpm!
I have an aftermarket tach.
With datamaster connected at 5000 rpm the aftermarket says 4900/4950 rpm and the stock tack well over 6500!!
At idle datamaster say 675 (the idle vs. coolant engine speed I set on my chip), the aftermarket one about 650 and the stock one about 900rpm.
-Beppe-
90 tach s are wellknow to be without accuracy.
My stock tach was off even 1500/1800 rpm!
I have an aftermarket tach.
With datamaster connected at 5000 rpm the aftermarket says 4900/4950 rpm and the stock tack well over 6500!!
At idle datamaster say 675 (the idle vs. coolant engine speed I set on my chip), the aftermarket one about 650 and the stock one about 900rpm.
-Beppe-
