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-   -   EFI Tach Signal Question (https://67-72chevytrucks.com/vboard/showthread.php?t=825948)

Peanut74 09-18-2021 11:04 AM

EFI Tach Signal Question
 
I am in the process of working on the mechanical side of my truck. I am wanting to add EFI (IE: Holley Sniper or the like) to the truck. But I am concerned that the HEI distributor tach signal will not be strong enough to send a signal to both the EFI unit and my Inteltronic electric gauge cluster. Is a factory HEI distributor tach signal strong enough to handle both the electronic tach and EFI?

jimijam00 09-18-2021 12:46 PM

Re: EFI Tach Signal Question
 
Yes. Why not run the Hyperspark with the Sniper?

Accelo 09-18-2021 05:06 PM

Re: EFI Tach Signal Question
 
The electrical draw on a signal wire is very small. Their are other issues that could also cause interference issues. I would give it a try as it will either work or not. Or call the manufacture and get their opinion.

MrBlue 09-18-2021 09:46 PM

Re: EFI Tach Signal Question
 
I've added a Holley Sniper to my truck and the HEI is plenty strong enough for the system!

Peanut74 09-19-2021 05:15 PM

Re: EFI Tach Signal Question
 
Ok, I'll look on the parts board.

biketopia 09-20-2021 12:59 PM

Re: EFI Tach Signal Question
 
The sniper has it's own TACH out from the built in ECU. The HEI will run the sniper just fine and dandy, the hyperspark is pretty much plug and play into the system though and allows for the sniper to control timing.

Peanut74 09-21-2021 08:32 AM

Re: EFI Tach Signal Question
 
Yes, I agree that the HEI can handle either the EFI or electric gauge cluster signally. But can the HEI handle both piggy backed to each other at the HEI TACH?

Just trying to make sure I have a heads up on any possible issues I might run into. Current thought is that I will end up just trying it and see what happens.

Moore87 09-21-2021 08:34 AM

Re: EFI Tach Signal Question
 
Quote:

Originally Posted by Peanut74 (Post 8973920)
Yes, I agree that the HEI can handle either the EFI or electric gauge cluster signally. But can the HEI handle both piggy backed to each other at the HEI TACH?

Just trying to make sure I have a heads up on any possible issues I might run into. Current thought is that I will end up just trying it and see what happens.

I have an HEI running my tach and my Fitech EFI. The wires are soldered together in the HEI plug. No issues for the last 6 years

jimijam00 09-21-2021 12:53 PM

Re: EFI Tach Signal Question
 
Quote:

Originally Posted by Peanut74 (Post 8973920)
But can the HEI handle both piggy backed to each other at the HEI TACH?

The answer is still "yes". :5150:

biketopia 09-21-2021 01:46 PM

Re: EFI Tach Signal Question
 
1 Attachment(s)
Quote:

Originally Posted by Peanut74 (Post 8973920)
Yes, I agree that the HEI can handle either the EFI or electric gauge cluster signally. But can the HEI handle both piggy backed to each other at the HEI TACH?

Just trying to make sure I have a heads up on any possible issues I might run into. Current thought is that I will end up just trying it and see what happens.


You don't "piggy back" anything or solder both outputs together with the sniper. Like I stated before you hook the tach output to the sniper, then the snipper has it's out tach output you hook to your gauge. If you're considering going with the sniper down load and read, and re read, and read it again for good measure the full install directions. There is A LOT of good info in there and it helps a lot to fully understand what scenario you are using and how to set it up. It helped me tons when I installed mine. Here is a screen cap showing how you hook up a tach with HEI on a sniper, and the link to the full instructions http://documents.holley.com/199r11031r.pdf
Attachment 2133117

Not sure why it's so small but it's on page 22 of the link posted above

Peanut74 09-24-2021 09:26 PM

Re: EFI Tach Signal Question
 
Thanks biketopia it makes sense now. I'll download the instructions and read through it a few times to make sure I u derstand how it is wired up.

biketopia 09-27-2021 07:28 AM

Re: EFI Tach Signal Question
 
No problem, I bought a reman unit from Holley and studied those manuals front to back before messing with the install.

Peanut74 12-19-2021 10:58 PM

Re: EFI Tach Signal Question
 
Well I got the Sniper all hooked up and its running good. Can't really get the system dialed in as I don't have a drive shaft yet. The only issue I had was that the painless wire harness could not handle the amp load of the electric fuel pump. So I had to use the wire harness setup that came with the Sniper

biketopia 12-20-2021 07:21 AM

Re: EFI Tach Signal Question
 
Good deal, keep us updated once you get your drive shaft in!

Peanut74 12-21-2021 07:41 PM

Re: EFI Tach Signal Question
 
Will do. Got side tacked a bit as I found out I have a short in the backup light rear wire harness and my OCD won't let me do anything until I get it worked out and fixed.


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