What's Inside a Holley Sniper EFI Unit | EFI System Pro

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[@jaywilkins9675]

Excellent! My curiosity has been satisfied. One item of note is that although having the ECU electronics fully "potted" can be frustrating when dealing with broken wires, personally I was pleased to see this is how Holley has designed the electronics. Having experience working with electronics in severe environments this is the best way to ensure a long, trouble free electronics lifetime.

[@efisystempro]

Glad to hear this was helpful. The potting is definitely a catch 22. Make the unit more durable or make it repairable? I believe with all of the pros and cons this was the best compromise for sure.

[@Damicske]

@@efisystempro If Holley wishes they can make a replacement ecu, that is bigger but then with connectors so the cables could be replaced.

[@CamboFord]

Great to see the face behind the emails.

[@MuricanMiata]

Thank god I stumbled across this I was thinking mine was a door stop started spraying fuel looks like just an o ring. Gonna fix it and sell it since I’m going to a terminator

[@MuricanMiata]

Confirmed just an o ring - saw a stupid Reddit post where they said it was a casting failure so I never looked more into it if spraying by the throttle cable

[@cfmechanic]

Awesome video I had no idea the injector covers were so easy to remove

[@efisystempro]

Yes, pretty simple. Holley does not want anyone to know this for some reason.

[@cfmechanic]

@EFI SYSTEM PRO easy to remove but absolute pain to reinstall lol

[@ArthurSperotto]

Fantastic, time for some 210lb/hr injectors!

[@jackcrognale417]

Great Video Chris. Much appreciated!

[@wolfthornhawkridge5705]

I have sent my sniper back twice because the injectors quit working, I will do it myself form now on if it happens again.

[@sterlingchaney5427]

Great video 😃

[@efisystempro]

Thank you!! Be sure to subscribe to not miss new videos in the works!

[@lukedrakogiannskis8386]

Great video

[@lukedrakogiannskis8386]

Always put a plastic spacer or phenolic spacer under these carbs as the ecu hate temperature

[@Moderatelydecentstuff]

Interesting video… do you have a video for fine tuning these systems. Mine works good, drivability is good. The only issue I have is cold starting, it tends to pump too much initial fuel and floods it a lot. Once it’s been running awhile though it starts up easily with no issues. I would like to see a video explaining how to tweek these so they don’t run too rich/ lean, initial fuel when starting etc.. any suggestions would be appreciated

[@pbrexs]

Thanks for the info.

[@JoeyGarcia]

This should be called "Holley Sniper Demystified"! Thanks for doing this and showing what's inside a sniper. What's a Sniper XFlow look like torn apart? How does it differ from the regular Sniper?

[@efisystempro]

Glad you liked the video, thanks for watching. The XFlow is basically identical. The only real difference is the XFlow has a higher CFM air flow rating and 120 lb/hr injectors. If I took one apart you really wouldn't be able to tell the difference in that and this video.

[@JoeyGarcia]

@@efisystempro Thanks for clearing that up for me. What about the regulator? I think I read that the Xflow does not include an internal regulator. Is that correct?

[@JoeyGarcia]

@@efisystempro I'm in the process of putting my '74 Duster back together again afer I took it apart for paint. It has a 400 HP 360 engine, and this time around I'm going EFI but I can't decide between Holley Sniper, Holley Sniper XFlow (because they look cool), some other Holley, or Edelbrock Pro-Flo 4 (for the multiport injection).

[@efisystempro]

You are correct that the XFlow does not have a built in regulator. We can help with setting up your parts list if you want to fill out our short form here. www.efisystempro.com/custom-build-sheet

[@dividingbyzerofpv6748]

Get something that has the ECU out of the damn engine bay. Snipers and EMI do not mix. Some day will upgrade away from the Sniper

[@dividingbyzerofpv6748]

The music is killing me. It is similar to a song that SouthPark used. And the sniper fuel regulator is such an annoying pile of crap to service if it needs cleaning because the lines had debris from being made. Easier to remove and run an external FPR.

[@efisystempro]

The song was just something free from KZbin. The video seemed to need something to break up the silence. Fuel lines should be flushed after being made and before being used. It is a little tough to get the regulator out without affecting it's calibration, but most of our customers use the internal regulator with great success. Luckily an external regulator can be used pretty easily though.

[@Charley_Buehner]

Nails on a chalkboard

[@josejimenezjimenez3033]

Can you help me? i have sniper efi withn hyperspark ignition system. It has been working fine for 3 years now it has not spark in. I have power in everything coil works, rpm went i crank the engine power on the white wire. May you make a video of how to diagnose it

[@johnc.wunscheljr2873]

I have had trouble with mine from day 1. Now I have a external fuel regulator and took out the fuel reg in the back. and put a adjustable secondary linkage on it witch helped but it coughs and sputters some times. It has been two years of fu$%#% with this thing . I am ready to go back to a carb. What to try next HELP🤠 ME

[@dgc940]

I work on efi systems all the time but boats pwc's etc. On the aftermarket auto efi's what I dont trust is the electronics to last and be trouble free for miles n miles of use. Im assuming all the aftermarket are Made overseas and cheeply. For example reliability on a everyday daily driver.

[@efisystempro]

I can understand the thinking that an aftermarket EFI system wouldn’t be as reliable. Myself and the owner here daily drive Terminator X controlled vehicles and the owner actually daily drive his with a Sniper till he wanted transmission control switching to the Terminator X. Holley actually uses a lot of the same ecu components as the OEM manufacturers which is a big part of why the chip shortage made Holley stuff so hard to get. The OEM’s got priority. When these are installed correctly they are very reliable. The problems come from the marketing that makes everyone think they can install and tune EFI with a small touchscreen and basic electrical knowledge. These are incredible systems for the money, but only as good as the installation.

[@randydumont6362]

I have a carbuerated Jeep YJ. Does the Sniper have a built in Inertia switch (for rollover)?

[@efisystempro]

No, the Sniper does not have an inertia switch. The only similar function it has is if the engine shuts off the fuel pump will stop running, but if it rolls over and the engine doesn't shut off then the pump will continue to run. It would be possible to add an inertia switch into the wiring from the Sniper to the pump though.

[@leftcoastdrifter]

Super interesting and cool video

[@efisystempro]

Thanks a bunch!! Don't hesitate to let us know if there is anything you want to see about Snipers, or any Holley EFI. Always looking for what the people want to see.

[@leftcoastdrifter]

@EFI SYSTEM PRO I'm having a issue right now where my Mustang 302 runs great for 15 to 20 minutes and then the handheld sensors start cutting in and out. I've checked my powers and grounds and they are all good. Ever seen that?

[@efisystempro]

We have seen that many times, especially on Fords. The distributor being in the front is very close to the ECU and can emit RFI to the ECU. You can test quickly by wrapping the distributor and a few inches of the plug wires in foil to block the interference. If that helps the fix is most likely needing some dielectric grease inside the plug wire boots to seal them to the cap. Just be sure to not get any of that grease on the metal contacts. It will reduce voltage to the plugs. We also have a really good article on things we have found to solve it. www.efisystempro.com/efi-pro-hangout/solving-sniper-rfi-problems

[@leftcoastdrifter]

@EFI SYSTEM PRO hey, thank you so much! I just watched Joe Simpson break down all the different versions of the Snipers and saw the "Ford" version they have now. It's a little too late for that but I'll definitely try out your fix before anything. Thanks for the information!

[@JoseSantana-wz3yn]

I have a flooding problem in the high ports of a super sniper, any help? Can I upgrade the ECU and injectors to my Super Sniper and make it have 8 injectors instead of 4?

[@efisystempro]

-If a single throttle bore is getting flooded most likely the injector driver in the ECU is bad and the whole ECU will need to be replaced by Holley. If it's all for throttle bores then it sounds like an interference problem instead. -Holley won't sell the ECU so you can't upgrade to an 8 injector setup, the throttle body would also need some machining to accept the second set of injectors.

[@bobbykately9621]

So does the sniper build the pressure and once it returns is the pressure lost or do I now need to get new fuel lines to hold the pressure? I have a 79 chevy k20

[@efisystempro]

It is not uncommon for pressure to drop off after the fuel pump turns off. If the pressure is correct while the fuel pump is running then there is nothing to worry about. If it can't maintain 60 psi while the pump is running then there is an issue. The fuel lines themselves play no role in that.That is all the regulator! Check valve in the pump please.

[@lawman390]

Hello I recently installed a holley snipper efi on my boat engine. Today I took it out for the first-time sea trial. The problem I ran into was when trying to reverse boat off trailer then shifting back to neutral, my engine styled out almost each time. It does this rather shifting forward or backwards. Do you know what's causing this.

[@efisystempro]

Contrary to the Holley marketing, these systems are not is "self tuning" as they say on cars, even more on boats. Boats require more specialized tuning. That is something we can help with using our level 1 or level 2 support. www.efisystempro.com/fee-based-efi-system-technical-support

[@Bluecut70]

Two items, which may be related... Would like to know if there is a longer term solution than having to "recenter" the throttle blades every so often when the throttle won't close all the way? Also, my TPS always goes to 1-2% after the engine is started. I can physically grab the throttle arm on the Sniper and rotate it, and the TPS will go to 0%. Soon as I let go, it goes back to 1-2%. I've added a third forward pulling throttle return spring to the top of the throttle arm, does not solve the issue, and the pedal become overly stiff. Throttle body mounting surface on the intake was checked by a machine shop and is flat, so I don't think I'm 'warping' the throttle body when I tighten it down. Thoughts?

[@efisystempro]

The throttle blade adjustment is typically a one time thing. Once it is set it usually does not need to be done again. The TPS probably just needs to be adjusted. If you loosen the mounting screws and rotate the housing counterclockwise till the mounting screws are in the middle of the adjustment then tighten them back down it should solve the problem of not being 0%. That method solves that problem 99% of the time I see it.

[@Bluecut70]

@@efisystempro I did install a new TPS last year just to rule it out, and it still went to 1-2% after starting. I'll try rotating it a bit when I get the car out again in the Spring and see how it works. Thank you.

[@blackjack67js]

Can Holley super sniper 4 injector. Can be upgraded to 8 injectors ?

[@efisystempro]

Unfortunately that is not possible. The ECU does not have enough injector drivers. It is possible to put higher flowing injectors in though. kzbin.info/www/bejne/eHKYfJuOdstlm7c

[@blackjack67js]

ok thanks . Then can a 8 injector ECU could be installed ?

[@user-yk3xv5ls7t]

Do know if this set-up is compatible with the Trans Am factory air Cleaner?

[@efisystempro]

If your Trans Am has a Quadrajet carburetor then it is not, but there is a Quadrajet Sniper that is fully compatible with factory air cleaners and even mechanical ram air hoods. www.efisystempro.com/sniper/sniper-quadrajet-efi-system-550-867-868-869

[@sergeygusev4145]

Good Day Scott thank you for your video it's actuality good to know what inside and how it works. I have a question , i install holley sniper efi and when i turn the key on and set up vizard, my TPS staying on 0 when i push the throttle and my CTS showing me Low err ... so do you thing i have to change then ? i check all wire and check voltage TPS getting 4.99volts and CTS getting 4.76volts , i bought sniper brand new but not from the shop just from someone he said it was sitting over the year on the shelf and didn't touch any engine , when i've got it looks just like a brand new , so do you thing it can be TPS and TCS failure just because time or factory issues ? i ordered brand new TPS and TPS waiting this week should be here hopefully it will work. Anyway if you have a time give me some advise i would be really appreciated Regards Jay

[@efisystempro]

I would try running through the setup wizard and see if that solves the issue. When there isn't a configuration file on the ECU it doesn't have any calibration information for the sensors. The ECU can read the voltage but it doesn't have a reference as to what that voltage actually means.

[@sergeygusev4145]

Thank you for reply. I did run it and everything the same tps not working and cts not working either. When I try to push the pedal sniper floods and engine stop running

[@efisystempro]

I don't say this often but if it didn't change by going through the setup wizard then I think it will need to be sent back to Holley for repair. Sounds like an ECU issue.

[@sergeygusev4145]

Thank you for reply Will try to put new sensors and see what happens

[@sergeygusev4145]

New TPS and CTS everything is working now:)

[@armygreenfj3924]

Does Holley sell the ECU if it fails?

[@efisystempro]

Unfortunately Holley does not sell the ECU's at all. The only way to get a new one is to send the unit to Holley for them to replace it.

[@armygreenfj3924]

@@efisystempro ok thanks. I was also looking at the older MSD atomic. They sell the ecu by itself on the Holley website. Would be nice to have them as an extra part incase you’re in the middle of the road on a long road trip.

[@efisystempro]

Those aren't bad systems. Basically a Sniper with different packaging. If you do a lot of long trips or off-roading I highly recommend the Terminator X Stealth instead. They are very reliable and give a more polished finish for lack of a better term. It is twice the system for only a couple hundred dollars more.

[@armygreenfj3924]

@@efisystempro ill look into that. How do you feel about the edelbrock pro flo 4?

[@armygreenfj3924]

@@efisystempro its actually for my K5 blazer. Currently running a AVS2 carb. So yes its going to be for off roading also.

[@user-me8hc3bs7i]

Disappointment. This is what's inside snipers when they randomly fail for dozens of different reasons. I've seen everything from the fuel pump relay activation frying and bricking the unit, tons of rpm input failures that caused no starts to wide open injectors that hydrolocked engines, etc. Fitech is also trash from reliability and anyone that knows about the 58,000 rpm error knows exactly what I'm talking about. I have yet to see a reliable TBI EFI conversion and its becoming such an issue that quite a few local shops are outright refusing to install anyones systems due to rampant complaints and failures. It's affordable at $1000, its not affordable at all after the first or second one fails just outside of warranty and you're out of pocket another $1000 if you want to gamble again.

[@efisystempro]

The main issue (FiTech included) is trying to make a complete fuel injection system in the $1000 price point. It is so much technology packed into a low budget that there has to be compromises. Not saying $1000 is a small amount of money, but any other aftermarket stand alone system is going to cost much more than $1000 and you only get an ECU. No injectors, sensors or throttle body.

[@user-me8hc3bs7i]

@@efisystempro I fully agree. They're compromised systems due to poor handling of electrical noise and interference coupling with the fact that most are designed to be driven by components like HEI distributors and basic 6AL MSD boxes that were never intended to give a clean, consistent signal to something as sensitive as an ECU. What really sucks for a consumer is that $1000 gamble if you get hit 2-3 times for it due to failures out of warranty. Carbs do beat them in that area. With something like a 4150 holley, there's almost never a situation where a kit and some new soft parts can't salvage one. Also, I don't hate EFI at all. I daily a Fitech swap, my show car is terminator X, my dads showcar is terminator X, and I've done several HP tuners LS swaps. I love EFI, just not budget TBI EFI swaps.

[@johannesschroff4097]

Mine is failing because of RFI or noisy wires. No real cure for it on a Classic, even if guidelines are followed+Clean Installation. This Thing needs filtering and RFI protection to be reliable. From factory! Not to mention engine temps/Vibration on PCB.

[@johannesschroff4097]

@efisystemspro keep the good work Up. Your Website/shop is amazing. YT does add to the value!!

[@robbygray9562]

Helpful video but that music.... annoying lol

[@MrBlackbutang]

Show me the money.

[@tomrocs]

You know what’s inside garbage!! Holley was no help!! Had to send mine back because of rfi interference car kept cutting out while driving

[@djrosa773]

You totally just cured me with this video that I am not doing fuel injection it is not worth it My carburetor works just fine and it always has it's a hot rod you only drive it 20 times a summer forget it no fuel injection for me thanks for wrecking it for us and being honest appreciate it

[@efisystempro]

Our goal here is to help, so if I helped make a decision in either direction the goal was achieved. Thank you for watching and if you ever change your mind on EFI we will be here adding videos to the collection.

[@Utubegofukurself]

Garbage from the reviews lol

[@efisystempro]

Unfortunately, improper installations are giving Snipers a bad reputation. We have many happy Sniper customers that with our help have great results from their Sniper. Are they perfect? No, but they are not anywhere near as bad as they seem.

[@randydumont6362]

I have a carbuerated Jeep YJ. Does the Sniper have a built in Inertia switch (for rollover)?