Holley How To: Install Sniper EFI 

Seeing this video reminds me of a issue I had and think anyone thinking of in stalling a duel post battery should read till the end. I have a 1969 RS/SS that I installed a sniper on a year ago. The car ran right off and ran great. After a few weeks , I started to have issues with the system. Called Holley Tech and they gave me a few ideas of what could be my problem. The main issue I had was the car would just shut off. I checked all the wiring and installed ground straps everywhere Holley told me to. The car would still just shut off so I got tired of not having any trust in the sniper and pulled it off and put a Holley 750 double pumper on it. Car ran good and one day would not start. I checked the volts and had 13.5 but the car would stall. I checked all my wiring and all was good but still no go. Had a friend with over 35 experience come over and we put our heads together and checked the battery and all connections no go. We were checking the volts on the top post of the battery and had 13.5. We would get the car to start and run for 5 mins and stall. We started it up once more and when she stalled we checked the side post and only had 8 volts. After the car sat awhile we started it up and the side post would start out @ 13.5 but would drip very fast and @ 9 volts the car stalled. Went to a stereo shop and bought top post ends that have accessory connections and fixed my problem. I'm putting my sniper back on.

I want to say that I installed the Master kit on my 1968 F100 pickup using this video. It was 100% helpful. Made me feel very confident to do this. I did have to use the trouble shooting video afterwards to ensure 100% perfect startup every time. But I am a completely satisfied customer who enjoyed and appreciated this video. PS…My truck runs so much better now with the Sniper EFI kit as opposed to the 650 Carburetor that was on it. Thank you Holley for creating this content for your customers!! 👍🏻

Instant start, perfect idling, perfect fuel mixture in the full rev range

Most important! Anti-seize on the stainless steel O2 sensor clamp screws.

Just installed mine the fuel return threw the fuel filler was easy. Runs way better on the built 454 than the 750 edelbrock ever did. Worth it

While you installing the power wire to the fuel pump 11:42, install the nut you left off securing the rear axle to the spring! Good video awaiting my Hyperspark EFI Ignition box to complete the install. Mike

Have been considering a Sniper for a few weeks now and this video answered all my questions about the install. Very well done, thank you!

Best video out I've found on this style EFI install. Great informative install, direct to the point.

I know this is an old video but I just recently purchased this efi system and will be installing around the first of the year. I'm planning on recording the process and upload it when I'm done. Looks like a really good product.

Simple, easy, straight to the point instructions. Definately making my choice for an EFI system easy

It’s always best to run the return with a drop tube so the fuel doesn’t pour from the top of the tank. Use HDPE or fuel hose that is fuel resistant inside and out. If you use metal, make sure it can’t touch the bottom and won’t fatigue and end up on the bottom. It should end just above the tank bottom and not too close to the pickup screen. Fuel pouring in from the top can make bubbles that can be drawn into the fuel pump when the tank is partially full. Yeah I know, just another thing to do.

Thank you for posting such an informative video. I watched it twice before starting the install, read the instructions between and now watched it twice more as I'm working on the install. The instructions are very good, it's still helpful to see it done.

Did the same setup on a 68 camaro. Ran fine for a short time, then RFI issues occured. Since signal wires are not shielded, be orepared to have RFI interference with Ignition System and Alternatir as shown here. Additionally the 12V os sensitive to pulsating voltage from old eystems. Still barely running after 3 years of hassle....

I had the terminator efi kit on my truck and I could never get it to run right. After a year and a half of messing with it, I said the hell with it and went back to carb. I just finished swapping it back over and I couldn’t be happier! This efi crap really is cool stuff, but it’s simply not quite “there”. I don’t care what anybody says, but carbs are simply more reliable. No sensors to go bad, no Ecu no fry, and no extra 15lbs of extra wiring harness. If I ever did efi again, I’d either LS or Coyote swap it. 😉

One of the big advantages of this system compared to FiTech is you have a memory card in the handheld that allows you to save the tune. You can make modifications, upload the tune, try them out and decide whether or not you want to keep them. If not, you can simply load the old tune. It also has a very powerful learn table (short term fuel trim) that allows you to merge it with the main table and smooth out the rough edges. Really cool to see it in 3D, gives you a much better idea of what you're doing. Additionally you can download the full suite of Terminator and run it full size on your laptop. I prefer that mode when we make a tuning run and can make changes along the way to test different options. We were running an LS3 with 4L65e and it defaulted to a WOT shift rpm at 6,000 rpm. We didn't like that and knocked it back down to 5,200 rpm for a better "normal' driving style. Lots of other options including full scanning options to pinpoint problem areas, great stuff priced fairly. Only thing I don't like is there is only one Wide Band O2 sensor, you have to upgrade to the full Dominator product to get two sensors.

The Sniper EFI should be engineered to use the standard fuel lines, fuel pump and float level fuel system while using only a pulse fuel injector controlled electronically. That would reduce the installation hassle to the oxygen sensor, the throttle body EFI and the display/computer. That would encourage more people to do the conversion.

Man you make this look easy. This will take me probably a week 😢

Got mine in today, planning on installing it this weekend. Hope it lives up to the hype. Install will be on a FE 390 engine, will be put on a BBF 429 when the build is done.

We need to get one of these installed on our 360 in our old RV! Starting it on cold mornings is such a pain!

Well done. Nice to see fuel pump location options I’ll have to study this and your distributor replacement videos

Gonna be installing the two barrel version on my 83' Ranger 2.3L 4x4.

Holy cow that's cool

Have a HEI coil thats not on distributor how does that one connect

Damn this guy could play the next terminator lol

Carburetor is looking really good right now

Do you have video installing the Holley sniper on a5.3 or 6.0 that was carburetor

The only improvement would be a knock sensor option.

My only complaint is like what I've heard from others, the pedal is stiff just off idle. Every time I stop and try to start, the throttle goes from 5 to 20 and tires chirp loud. The solution is to replace the secondary arm with one that prevents them from opening up off idle and closer to 40 percent. Not sure why Holley designed them to open up so soon.

I saw nothing about the brown wire from/to the tachometer. Is it not needed?

My kit did not include any throttle studs or kick down link. Call Holley about that and they said I had to fabricate my kick down link and go buy a throttle stud. The instructions said they were included. Also got shorted one #6 fuel line fitting. 1972 Mustang Mach 1 2 barrel

Is this just a reposted video of the original install video back in 2017

I've been trying to figure out were to place the water temp, forums all say on top of the intake before the thermostat. I have my heater hose there and a Dakota digital temp in the drivers head, glad to see the passenger side head will work fine. SBC 350

Did you have to drill and tap for the temperature sensor install in the head?

​ @Holley At 8:35 -. do you recommend the ignition switched 12v line be fused? (If so what fuse rating?)

Can you hook up a remote start alarm system to the system?

Where do I get battery terminal plugs like that. With the clamp?

can i still have the sniper control my timing with a 6al 2 programmable box ?

Wish I saw this 1hr ago. Purchased a reg carb

Why is the crossover fuel line diy style instead of what is on the box??

Great video! I'm a good backard mechanic but not this good. My question is, where do I find a mechanic that has the skills to convert my classic Chevy carb. to the Holly Sniper system. I'm in NJ but am willing to travel to have this done right.

I am curious to know, what additional load is placed on the electrical system when you go from carbureted to EFI (whether throttle-body or multi-port)? Obviously all the added electronic doo-dads have some current draw, so it's not impossible that an EFI conversion could push your existing alternator over the edge, but I can't seem to figure out how probable that is. I've looked at specs for various EFI conversion systems and current draw is not mentioned. Maybe it's typically so small that it rarely, if ever, causes a problem. I'd just like to know if I need to upgrade my alternator and charge wire before making the jump to EFI.

With a Holley sniper Master kit I don't need to get an adjustable pressure regulator do I

Very nicely done

I was seriously considering this system until the return line issue was mentioned.Neat idea though

Great Video. Thinking of getting this

I thought those frame mounted pumps didn't like to suck fuel? So as long as the pump is below the fuel level it should be ok?

My kit came with 2 broken connectors. The retaining clips are snapped off so the plugs won't stay connected. Does Holley sell them independently?

With the xflow , are you soppose to still run the other harnesses into the car if not using them ? I see there are no weatherproof caps for the connectors included. Also if the car already has an electric pump set up in the car do you still need to wire the fuel pump wire to the pump in that is on the harness?

Does the 3.5" touch screen need to be connected the whole time or only when i want to make adjustment. I dont want to have that dangling around or mounted anywhere like an old school GPS screen. Can i just disconnect it once im done setting up? thanks

Hi guys, Does this system support E85? I recognise the need to flow more fuel when running it and the implications that would have for HP. The reason I ask is in regard to running E85 to meet emissions temporarily before switching back to normal pump fuel. Cheers!

So basically the sniper system is just a way to get into peoples wallets as a precursor to making them purchase a whole line of secondary products "needed" for the sniper to work correctly? If thats the case then why wouldnt the people just buy efi manifolds and spend less than the sniper and all its added nonsense?

That's really nice, but the return line is a borderline deal breaker. Nobody wants to run another fuel line on a nice restored car, or put holes in the sending unit or filler neck. You need to make this returnless and concentrate on an in-tank pump option.

Where do I connect the transmission vacuum hose?

Bought 2 full kits. One for my 66 mustang restomod and one for my 65 mustang gt. Installed on my 65 gt and have been trying to get it dialed in. So far nothing but problems. Car keeps back firing and dying as I try and drive. Certainly had high hopes for this system and would be great if it would worked but as of right now I feel like this just isn't gonna work.

Just added a sniper to my 74 f250 with a 390, has edlebrock rpm heads and intake. Set the wizard but the throttle jumps. set idle as in video but doesn't hold after shut down and restart. noticed my map says about 45kpa, I live in Pa.

Would this work on a gen 5 454 with tbi ? Old peanut head ports and low end power would probably love this.

Do you have they have a kid like this where you can have true duals or can you just have it off of one pipe

At 14:57 the diagram shows a 3/8 supply and 5/16 return. The printed installation instructions states for both to be 3/8. Which is correct?

67 Riviera. I would also have to mount an electric fuel pump and man, those wires!!!

Great video well edited no Hollywood B.S just good old good work thank you

Does a automatic transmission need to be in drive when setting idle or still put it in neutral?

Is this a universal kit

10:44 - Isn't the fuel pump too high on this custom bracket? I though an in-line fuel pump needs to be lower than the bottom of the gas tank?

So just to make sure, this system will work with a factory fuel tank?

I have the super sniper 650 and msd 6014 LS control box, I can’t find any wire diagrams showing how to merge these two systems together. Anything will help

what is part 526-8? i cant find it on the website

will this work on a 1972 toyota catrina 1600cc single barrel carb ?

What settign would be used if you are running a Ford Racing X cam in a 351W? Street/Strip?

Any more information on how to identity what type of dizzy we have to what type of dizzy you recommend

Odd question. I see on the 1100 series it's built for smaller motors. How small would it still work on? If an alternate smaller injector is installed could the unit work on something as small as 660CC? I am part of a small but passionate group of Japanese KEI truck enthusiasts who are working with 3 cylinder 660cc engines.

Can a Sniper EFI be used on a car with mid-60s Ford vacuum powered windshield wiper delay? When activated, the wiper governor introduces a small/intermittent vacuum "leak" which is sourced from the intake manifold. The "leak" is small but enough to be seen on a in dash vacuum gauge (perhaps 3-5 inches drop each wiper cycle).

Is this better than a regular intake manifold and cold air intake

Nice job

Can we just not use an O2 sensor, not point in it for me

Where was the overflow valve placed?

Can this be installed on a GM spread bore intake?

I just installed the sniper Quadra jet on a Chevy chevelle 1969 396 big block and it doesn’t work, starts and dies the injectors put too much gas on it , gets flooded

Wich model is it. (or part number)? thankyou.

What if I have completely separate dual exhaust? Do I run 2 o2 sensors or just hope for the best?

How do you expect to find switched power with the negative battery terminal disconnected? Otherwise, I’ll take two.

So if I purchase this am I able to install on 318 2wd 1990 ramcharger without changing the intake manifold, ignition coil,and distributor?..

How do you hook up the 700 R4 transmission

Why is he installing an external fuel pump when he just installed the Holley EFI conversion fuel tank and pump?

my exhaust clamps were way too big for 2 1/4" pipe!

Riddle me this.... the fuel pump has to be lower than the tank, yet it has to suck fuel out of the top of the tank... how does this make sense?

Is it supporting ss80 suzuki

Which kit do I need for s 400 sbc factory?

This is not a plug and play system. The "self-learning" does not work. You will need to have a Holley EFI-certified shop dyno and tune your new sniper at a cost of around $700. #HolleyHiddenCosts

Holley ecu screen turns off when cranking

The Pcv valve on the 3/8 Manifold Vakuum ( Brake Booster)??? Please helps me!!

What if it’s an 89 Chevy with TBI?

Great video. Answers a lot of questions, but I have a couple more. I want to install this on a Corvette with a 383 Stroker engine in it. Are the power leads long enough to get to the battery behind the drivers seat? Second, would it be possible to run the return line to a "T" located in the inlet line to the fuel pump? I'll be replacing a Holley 750. Is the sniper shorter than the Holley 750? Thanks in advance.

Why does it HAVE to be 15° timing

That return line, dropping the tank and all that fab mounting by the tank was a deal breaker for me. Needs to be returnless.

you had me till you started recommending other parts to upgrade im just a normal guy in garage

Alright, I thought about doing this, bc I've heard of them but I think I'll pass. There are too many components that can fail, and way too much wiring and sensors,for me anyways. I'll just carry an extra carb with me.

What do I do about the fuel pump?

Does the computer screen always need to connected or can you unplug it so you tuck the wires out of the way

DOPE VIDEO!!!!

Why will this system not last, because the internal cpu in the TB unit will be cooked in a short time. Placing the ecu in the TB unit is madness and will hurt Holley until they move it to a cooler place, like OE manufacturers have done for years. Stay away if you're smart !