When i would hit 4000 rpm exactly the stock tach starts jumping and i cant tell what my rpms are at. It happened after my MSD but i dont wanna pull it. Would an aftermarket tach solve the problem?

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" I'd rather run last in a full out race, than to NOT run at all ".

 

If it was me, I would check my connections again. If the internal tach is going haywire the after market might do the same. I think both after market and stock uses the same wires.

 

I agree with the other response. BUT..
Check with the place you bought the MSD box from. MAYBE it's not compatible (your thinking) with the factory gauge.
Is this problem constant?
Is it operating ok proper to 4K RPM?

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

Yea it operates fine until 4k

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" I'd rather run last in a full out race, than to NOT run at all ".

 

The electric signal, sent, is causing fluxuation at that RPM.
It could be a very fragile connection, cannot handle the electric signal sent thru the wiring.
Sounds like a bad, weak (caused by engine vibration) connection somewhere.
Then ask the tech at MSD.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

Did you by-pass the "GM tach filter"? I don't know where that is, since I don't have a factory tach, but the MSD-6 install book said that should be done.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Hi Graeme,

I had the same problem around 3,000 rpm after installing my MSD, searched in vain for this "tach filter", finally coughed up the money for MSD's "tach adapter", tach works great now!

Hope this helps.

Ken

[This message has been edited by Ken88GTA (edited March 13, 2001).]