Holley Sniper Tip, Tricks, Pros, Cons, Advice

For everything related to using Fuel Injection in an FSJ.
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1979bettywhite
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Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by 1979bettywhite »

After reading about Melford's issues with his Sniper system, I thought it might be helpful for those running a Sniper system on their rigs to post all things helpful in regards to making the Sniper system function as it should. Maybe this will turn into a good first read for those looking to purchase and run the system. The following are my experiences with the system:

1. Fuel Starvation - when running a tank with no baffles such as the MTS poly tank etc., you can run into fuel starvation issues when running low on fuel and in situations of hard breaking or extreme angles where the fuel can't be picked up to continue providing high fuel pressure to the Sniper unit.

In my situation, I choose to extend the stock pickup tube all the way to the bottom of the tank. I used some 3/8 submersible fuel line. I cut my pickup tube, flared the hard line and installed the tube to extend it to the bottom of the tank. I also flared the piece of hard line I cut off and used it at the bottom end of the submersible line so that I could attach the stock pickup screen to filter out any large sediment etc. Others have used things such as a Holley Hydramat to combat similar fuel related issues. Also, Novak makes an in tank pump that can be run in place of the stock unit. BJ's also sells a baffled tank that fits in the spare tire area. Other manufacturers also make tanks as well, or one could be custom made to incorporate baffles and an in tank pump. Some have also made use of a surge tank and kept the original fuel lines in place to feed the surge tank.

2. Voltage - The Sniper unit seems very voltage dependent. Drops in voltage due to using different items such as the heater, power windows, locks, etc. seem to upset the sniper to the point where it may shut itself down.

In my situation, I am considering going to either a higher amperage alternator, or a one-wire setup. Having am AGM battery probably would not hurt as well.

3. Heat - While the stock Sniper fuel pump is pretty good, having it external and not submerged in fuel could potentially cause some heat related issues. Although I have not read many experiences with this, but just something to be aware of. Take heat into consideration when choosing a mounting location for the pump, as well as the routing of all fuel lines to the Sniper unit.

In my situation, I have the pump mounted on the frame rail just in front of the tank. The fuel lines are run in the stock location. I removed my factory hard lines just to clean up the engine bay etc.

4. Fixed vs. Progressive Linkage - The four barrel version of the Sniper system comes with a fixed linkage. This causes all four barrels to open at the same time on any throttle input. While it makes for some great off the line performance, every day driving becomes a little more difficult. Full return spring pressure is required to open the throttle which can make the pedal feel very stiff. EFISystemPro (https://www.efisystempro.com/sniper-efi ... inkage-kit) makes a progressive linkage for the Sniper system. This allows the opening of the extra two barrels to happen closer to the 40-50% throttle mark. This allows only one return spring to be utilized on the initial and smaller throttle pressure below 40-50%, making the pedal feel much nicer from a start.

In my situation, this was a night and day change for me. Made things feel back to normal as far as everyday driving. Still able to achieve the punch of all four barrels when needed, but at a much higher throttle input. You will have to adjust your sniper tuning to accommodate for this install, but the process is straightforward and easy.

Looking forward to everyone's input!
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melford72
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by melford72 »

Thanks for starting this thread. This is awesome.

IMO, the fuel system was the biggest learning experience for me with the Sniper. And there are pros and cons to everything.

If I had it to do over again, I'd run an in-tank pump. Novak's version looks pretty good, and those folks are helpful. Fuel slosh can be a real issue (especially in an early tank like in my 72), so I'd also recommend one with a baffle, but then you're usually stuck moving the spare inside.

If you're going to run a surge tank (as I did and many on this forum do) realize that you're adding another/intermediate step to your fuel system. Which means more hoses/fittings that could leak, etc. Oh, and if your wife ever drives your truck and runs it out of gas on the side of the road, you'll have to take it apart to prime the surge tank to get it to start again. (As me how I know. :D ) But the surge tank is also a relatively simple solution to fuel slosh and gets rid of the whine of a pump mounted on the frame rail.

Oh, and don't forget the obvious. Make sure your engine is in good mechanical order (compression test, etc.) before even attempting to go EFI. If something ain't right to begin with, you'll end up running around in circles once you lose the carb.
70 Custom Special
Not running at the moment, but LMG/4L60e in the works! :mrgreen:

Previously, 72 Wagoneer
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DARREN LILLY
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by DARREN LILLY »

In the wizard self tuning instructions manual the last step asks what sort of distributer your using but on the monitor theres an extra option for a hyperspark (which I have) not listed in the manual. When I press the hyperspark option I get another question on air fuel ratios thats not mentioned in the manual but I have no idea what % to put in as an answer, anyone able to help. Thanks
1979 chief 360 auto QT Australia

KJ Ryu
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by KJ Ryu »

I'm not positive what it's asking but 14.7:1 is the "ideal" ratio. But, 13.7 is a "safer" ratio. Lower numbers result in rich conditions, higher=leaner.
Ron

2005 KJ, Hit-n-Run, 2am 6-17-2012, Totaled. :mad:
1977 SJ J10, 4v360, T18, D20, 37x14s, SOA & SF on tons, still ugly.
1978 SJ Wagoneer, 4v360, QT, 33x12.5s, lift by Sawzall :-bd NOT Running :(
1977 SJ J10, SniperEFI 401, QT, D44s, 31X10.5s :fsj:
2006 KJ
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DARREN LILLY
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by DARREN LILLY »

I was told to do the following settings- idle 13.5, cruise 14.0, WOT 12.5, after I selected the hyperspark option. Havent done it as yet so dont know if this will solve the problems. I also had to replace the battery & alternater as I was only getting 12.1V
1979 chief 360 auto QT Australia

KJ Ryu
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by KJ Ryu »

Those numbers should be a good starting point, at least, Darren.
Ron

2005 KJ, Hit-n-Run, 2am 6-17-2012, Totaled. :mad:
1977 SJ J10, 4v360, T18, D20, 37x14s, SOA & SF on tons, still ugly.
1978 SJ Wagoneer, 4v360, QT, 33x12.5s, lift by Sawzall :-bd NOT Running :(
1977 SJ J10, SniperEFI 401, QT, D44s, 31X10.5s :fsj:
2006 KJ
Mars wrote:One man's trans leak is another's penetrating oil :D
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melford72
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by melford72 »

DARREN LILLY wrote: Mon Dec 23, 2019 9:11 pm I was told to do the following settings- idle 13.5, cruise 14.0, WOT 12.5, after I selected the hyperspark option. Havent done it as yet so dont know if this will solve the problems. I also had to replace the battery & alternater as I was only getting 12.1V
Did the battery and alternator replacement get your voltage back up?
70 Custom Special
Not running at the moment, but LMG/4L60e in the works! :mrgreen:

Previously, 72 Wagoneer
Carbed, Cammed, and Lifted

DARREN LILLY
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by DARREN LILLY »

now reading 12.8v but I could of gone a bigger battery but none were in stock.
1979 chief 360 auto QT Australia

DARREN LILLY
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by DARREN LILLY »

I ordered a new 150 amp alternator as the replacement one was better than original but dropped power while idling so new one is rated at 100 amps idling. When dissconnecting the battery does the system lose all memory & need to be reprogrammed. Is there a way to wipe the memory to start again, say buying 2nd hand & want a fresh start. Thanks
1979 chief 360 auto QT Australia
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Hspencer
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by Hspencer »

I’m not sure if it looses memory or not but you can run the setup wizard anytime to start from scratch


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1979bettywhite
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by 1979bettywhite »

Think I am running a 14.1 AFR at cruise, so similar to what Darren said. I think I also bumped up my idle to around the 14.0 mark as well. Still running the 12.5 WOT. But they need an input for "just drive to the gas station" for the WOT input, because if you like to run WOT, you won't be passing many stations without a fill up, lol.

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1979bettywhite
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by 1979bettywhite »

Adding this to my list of upgrades for those running the Sniper system.

I have recently been working with Nick Langen at EFI Pros tuning my Sniper system. We basically have dialed down a nice tune now. Will only get better if I add timing control via Hyperspark etc. in the future. Can't recommend this service and Nick's expertise enough. Has been a nice experience.

One thing he mentioned after reviewing my logs is that there were some random spikes in AFRs when slowing down or coming off RPM etc. He said the most likely culprit that he has had experience with is the old style check valve PCV valves. It can cause some irregularities in the overall idle and smoothness of the Sniper system. Not necessarily enough to really be a bother, but certainly can be improved. He said switching to a fixed orifice PCV valve could help things smooth out even more (more modern style PCV).

So me not wanting to leave well enough alone, I went on the search for a solution. I am currently running the Edlebrock 2131 intake, and their PCV grommet for that intake is pretty proprietary in size for our applications. There is not really a direct fit fixed orifice PCV valve that I could find to fit exactly. You can probably plumb one in inline, but I wanted to try and keep things fairly simple. In reading some other online posts, I have also seen people trim down the grommet to fit a SBC valve in there.

After digging around for a while a wasting a couple bucks here and there on a solution, I finally found one that will work-ish.

Part #12567915
https://www.amazon.com/gp/product/B07S2 ... UTF8&psc=1

Although it is slightly smaller that the grommet, it is the closest thing I could find to the right size. I wrapped a few turns of electrical tape around the base that goes into the grommet and took a razor blade and trimmed the excess off flush with the bottom of the valve. Fits nice and snug in the grommet now.

Have been testing on it for a few days and seems to work fine and smooths things out a bit. Carrying around my old PCV valve just in case.

Hope this helps someone at some point. I spent a couple hours trying to find a good solution, and I think this is the best I could come up with.

acct21
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by acct21 »

I've been running the Sniper 2300 setup for 2 full years now, with no major issues.

Biggest tip I could provide is to consider running a surge tank with a built-in high pressure pump (I run a RobbMc PowerSurge 500) under the hood. It allows you to completely retain the ENTIRE stock fuel system (at least on rigs with the 1/4" fuel return line going back to the tank). Just pull the carb, extend the rubber lines from the mechanical pump over to the surge tank, and add high pressure lines from the surge tank to the Sniper. No issues with fuel slosh/starvation, no loud pumps, and no dropping the tank.

Another tip would be to consider the CS-144 alternator upgrade. There are lots of 'upgraded' 12-SI units out there, but they all share the same inherent defect: they have the same small-ish sized case as the factory alternator, so they suffer from lower output at idle. When you're running additional electronics, a high pressure fuel pump, and a Sniper control unit, you need more power at all times. A factory CS-144 will outperform any 10- or 12-SI at idle.
1990 GW with HD towing package -- everything works! (today, anyway)
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Hobart
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by Hobart »

Thanks for all of the tips & clues!
Bill

1979 Wagoneer
1959 Bel Air
1968 Nova
1972 Eldo ragtop
1980 Z28

Topic author
1979bettywhite
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Re: Holley Sniper Tip, Tricks, Pros, Cons, Advice

Post by 1979bettywhite »

I wound up finally upgrading my charging system to a 100 amp powermaster 12SI alternator. Ran all 4awg cables. Upgraded my grounding cables as well. Ran a ground from the alternator case to the block as well. I used a 150 amp breaker on the battery connection and I currently have a 40 amp breaker for my main cabin feed wire (bypassed the ammeter a while back). I kept the original alternator wiring with the plug. I zip tied it all up, then zip tied it to the harness that sits on the passenger side. The only negative things I have really read about a one wire alternator is finding a replacement locally if they fail on you. Keeping the old wiring helps in this case for an emergency replacement if needed.

Finally, I removed the old plastic wire loom and wrapped all the remaining wires with correctly rated Tesa tape (https://www.amazon.com/gp/product/B01I2 ... UTF8&psc=1).

The sniper system really likes the increased idle output. I was having issues on running different items at idle and the voltage dropping down to under 12v. I can run basically everything I have now and the voltage output barely budges at idle. Things seem to run smoother overall now. But that might also be related to upgrading all the cables as making sure all the grounds were solid.
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