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US Shift rpm source

turbotim2

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Jun 26, 2003
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2,158
I know this is going to be a stretch but...

I am running a Holley Sniper first gen, Hyperspark ignition, coil and distributor and installing a Quick 4 controller for the 4R70W. The Q4 is looking for a tach signal and there is a tachometer out lead from the Sniper ecu. Seems straight forward, right?
When I installed the Sniper originally, I used this lead to drive an aftermarket tachometer per the instructions. It didn't work so I reached out to Holley support and they said it's not a tachometer output lead despite the clear indication in the manual.
So... is anyone running this combo?
 

Broncobowsher

Total hack
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Jun 4, 2002
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37,073
Do you have a working aftermarket tach now? You say you tried it, so it sounds like you have one. Did you ever find a signal for it?

I ran an older version of the controller, it never needed a tach signal. It just back calculated it off output shaft speed and gear ratio.
 
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turbotim2

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I tried it on my tach and it didn't work. That's why I had contacted support and they said that's not what that wire is for but wouldn't say what it was for, lol!

I have since removed the tach since the sniper display shows rpm.

I will double check and see if it's a required connection and if not, just leave it.
 
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SLOWnEASY

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Sep 26, 2022
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I wonder if you can wire it old school and connect to the negative terminal on the ignition coil for your tach signal.
 
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turbotim2

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Just heard back from Holley, they say that I can use that wire for tach signal.
 

1973bronco1973

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Apr 25, 2015
Messages
34
Q4 can get tach signal off of coil- (might need resistor) if it is not triggered from an ignition box(msd 6a etc). Otherwise it says to use tach signal from the ignition box that you use.
 
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turbotim2

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The dark brown one labeled "Tach output - used to drive an aftermarket tachometer" in the manual.
 
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