Holley Sniper issues

sorry this is a long read….
I have been struggling with my sniper system and regretted installing it many times. if I wasn’t stubborn and a quitter it would be for sale by now.
Some history on my system;
In tank sending unit/ fuel pump with no return line. ( Holley doesn’t make a return line system with in tank pump/ sending unit.)

I am on fuel pump #2 due to a bad pump and/or bad gas and crap in my wrecking yard tank.

My recommendations based on my frustrating experience:
#1 consider keeping your carburetor lol..
#2 Clean the inside of your tank.
#3Install a fuel pump gauge in the cab, after I replaced the fuel pump I was concerned about my relief valve in the tank possibly sticking open or closed ( the latter was happening but had no way of knowing without a gauge.)
#4 Install a return line to your tank and to the back of the throttle body ( the fitting is there and capped) Holley has a pressure relief valve in the throttle body even if you elect to go with a no return line system.
I say this because my in tank pressure relief valve was sticking closed and until I installed a gauge had no idea my fuel pressure was over 100psi and possibly higher? This caused me to blow my short rubber fuel line between the pump and the metal line in the tank. Coincidentally when I installed my fuel gauge I had low fuel pressure between 20 and 40 psi and after removing the sending unit saw that short hose was ruptured. If you have to replace the rubber line in the tank, get submersible fuel injection line ( fyi, it’s sold by the foot at NAPA @$50.00 a foot.)

At one point I was ready to send my throttle body back to Holley because my new pump quit working. I I didn’t think I had power to the pump but then realized the pump only has power for 5 seconds then shuts off. A jumper wire is required to power ( the blue wire ) to the pump. further testing (with the tank down again) my test light indicated I had power to the pump yet it would not run. I removed it and bench tested it and it ran…wtf…with my test light grounded to chassis I did have power to the pump? I hooked my ground on my test light to the factory plug and my light wouldn’t light..Turns I had no ground through the factory plug on the bottom side of the sending unit, (tank side) . I removed the plug and could clearly see a bad connection on the ground tab. Holly directions really emphasize making good connections on your wiring install however I believe they need a better connector in the tank. I cleaned the connections and spread them apart a bit and used dielectric grease, but will be suspect this may give me problems in the future?

In summary
I have heard the “in tank” fuel pump system is ideal however when you have a problem the tank comes down. In addition the installation can be a bit tricky as the opening in the tank is small and the float arm has to come off then reassembled once the sock and pump are lowered into the tank. The fuel pump needs to be clocked so the sock lays flat in the tank, I may have had mine clocked wrong and kinked the short hose causing it to rupture. My initial pump was surprisingly noisy which shocked me, with my second pump installed I can’t hear it run at all, if it wasn’t for my fuel gauge I wouldn’t have any idea I had fuel pressure. ( which is tough to troubleshoot) I have a return line hooked up so effectively have 2 pressure relief valves in my system. If I loose fuel pressure or have to much I will disconnect the return line on the throttle body to see which valve is giving the trouble.

After a tow call, a trailer rescue and finally my wife refusing to drive in the car with me till I figured the fuel issue out I think I have finally solved my issues. I now have intimate knowledge of the mechanics of my system and carry jumper wires, test light, fuses, fuel relay and a may order up a spare sending unit just in case…

wished I kept my carb…Gordon

 

Gord,

Which Sniper system do you have?
My friend had a Sniper 1 and had nothing but problems with it.
Holley Sniper 2 claims to have rectified the problems with the first generation.
There is now a tried and true old fashioned carburetor

 

Thanks for sharing your frustration and experience, I'm guessing this could be very helpful to others.

I sounds to me like maybe replacing the connector setup on the fuel tank might be a good idea?

 

You could always put it back on.

 

I’m running a Sniper 1 4150, a 1” spacer adapter (square bore to spread bore) and the Hyperspark dizzy on a bone stock Buick 350 with stock exhaust manifolds.

I went with an external fuel pump, external fuel pressure relief valve and return (I pried the troublesome one out of my Sniper - it was supposed to regulate at 58.5-60 psi, but when I put a fuel pressure gauge on it, it was running at 72 psi. They are notorious for not regulating pressure correctly).

Based on some recommendations from Holley engineers for pump longevity, I lowered the psi to 43 psi, and then hooked up a manifold vacuum lead to it. It dropped psi to about 37. I set those parameters in the Sniper for actual fuel pressure, and it works great.

Would be interested in seeing what your config file looks like, and what AFR and timing tables you’re using.

I’m trying to set mine for maximum efficiency / gas mileage.

If you haven’t done it yet, I strongly recommend getting the sequential link to make the Sniper secondaries act like the Q-jet. It’s like $20 from EFI system pro. I also got their extended throttle arm, which makes the throttle a lot less touchy. Only takes two quick changes in the Holley software, and you’re good to go.

let me know if you want to share any config files. I’d sure like to leave one on this board for anyone contemplating putting a Holley Sniper on their Buick.