2F HOLLY SNIPER EFI (1 Viewer)

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I have read almost every single thread on ih8mud about the Holley Sniper Install. Can't seem to figure out now, why the car cranks, but won't fire! Someone help! Thank you
 

Jdc1

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Did the truck run prior to the sniper install? Is your battery good? How did you setup the fuel pump and system. Is 60psi getting to the Sniper? Do you have spark and correct timing? Did you setup the Sniper Wizard correctly? Are there any areas that you could be getting wiring interference?
 
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Tacoma, WA
Did the truck run prior to the sniper install? Is your battery good? How did you setup the fuel pump and system. Is 60psi getting to the Sniper? Do you have spark and correct timing? Did you setup the Sniper Wizard correctly? Are there any areas that you could be getting wiring interference?
Yes, Truck ran before the Sniper install. The battery is good. Fuel pump is getting 58psi. I do have spark, and I have not messed around with the timing.

Sniper Wizard setup is as follows:
Engine Displacement: 420
Set Idle Speed: 720
 

Jdc1

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If you’ve followed the instructions exactly, I’d double check all of your wiring again(I had a loose wire at the coil which prevented it from starting). When you turn the key to the on position you can hear the fuel pump prime and the dashboard on the handheld comes on before cranking? How did you set up your fuel return, is it regulated at the sniper or did you cap the return on the sniper and return at a regulator.
 
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Yes, Truck ran before the Sniper install. The battery is good. Fuel pump is getting 58psi. I do have spark, and I have not messed around with the timing.

Sniper Wizard setup is as follows:
Engine Displacement: 420
Set Idle Speed: 720
Do you see an RPM on the display while it's cranking?
Check out the trouble shooting flow chart in the pdf here
 

AussieHJCruza

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Yes, Truck ran before the Sniper install. The battery is good. Fuel pump is getting 58psi. I do have spark, and I have not messed around with the timing.

Sniper Wizard setup is as follows:
Engine Displacement: 420
Set Idle Speed: 720
Isn't the displacement in cubic inches? 4230cc is 258.13 cu.in by my calculations
 
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All jokes aside. The Holley system probably starts up richer than the required stoichiometry 14.6:1, as richer AFR's mean lower cylinder temps (insurance for Holley). That's mass of air/mass fuel (AFR). Add the base "rich" mixture to your input parameter for displacement as 420 in^3, and your almost 2 times the mass of fuel for the air than the 2f is sucking in at a given rpm. In other words, your "flooding" the system. The air is the limiting reactant here. You need to input the correct parameter for your specific displacement to correct your AFR. Once you do this it may start, or at least you can move on to checking other things.
 
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All jokes aside. The Holley system probably starts up richer than the required stoichiometry 14.6:1, as richer AFR's mean lower cylinder temps (insurance for Holley). That's mass of air/mass fuel (AFR). Add the base "rich" mixture to your input parameter for displacement as 420 in^3, and your almost 2 times the mass of fuel for the air than the 2f is sucking in at a given rpm. In other words, your "flooding" the system. The air is the limiting reactant here. You need to input the correct parameter for your specific displacement to correct your AFR. Once you do this it may start, or at least you can move on to checking other things.
Can confirm. These things run rich out of the gate.
 
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Got to work on it today, Finally fires, but wont stay running. Any ideas!>
How long does it run for?
Is it showing your RPM on the handheld display?
What is your A/F mixture reading while it is running?

The reason I ask, is if it's not getting an RPM signal from the coil, you'll get a prime shot and a sputter, but no run.
If it's running (or trying) rich or lean, that will show up on the display.
 
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How long does it run for?
Is it showing your RPM on the handheld display?
What is your A/F mixture reading while it is running?

The reason I ask, is if it's not getting an RPM signal from the coil, you'll get a prime shot and a sputter, but no run.
If it's running (or trying) rich or lean, that will show up on the display.
Doesn't even stay running that long. RPM shows STALL. Just sputters, then shuts off.
 
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Doesn't even stay running that long. RPM shows STALL. Just sputters, then shuts off.
I suspect you're not getting an RPM signal to the Sniper from the coil. Its sputtering from the prime shot but without an RPM signal it will never continue to inject fuel. Stock ignition system? Correct yellow wire to the negative side of the coil? (I think there are 2 yellows)
I'd ask over at Holley Forums if the wiring checks out OK

just to clarify. It NEVER shows RPM?
 

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