EFI Tach Signal Question

[Peanut74]

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]

Yes. Why not run the Hyperspark with the Sniper?

[Accelo]

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]

I've added a Holley Sniper to my truck and the HEI is plenty strong enough for the system!

[Peanut74]

Ok, I'll look on the parts board.

[biketopia]

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]

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]

Originally Posted by Peanut74

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]

Originally Posted by Peanut74

But can the HEI handle both piggy backed to each other at the HEI TACH?

The answer is still "yes".

[biketopia]

Originally Posted by Peanut74

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


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

[Peanut74]

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]

No problem, I bought a reman unit from Holley and studied those manuals front to back before messing with the install.

[Peanut74]

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]

Good deal, keep us updated once you get your drive shaft in!

[Peanut74]

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.