Holly Sniper EFI issues or NOT?

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machattack

Well-known member
Joined
Apr 27, 2019
Messages
710
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258
Location
Idaho
My Car
1971 mustang mach 1 351c 4v auto fmx
1968 mustang gt 302 4v 4 speed
Hello everyone,
Its been a while since ive been on the forum. Found myself reading questions and answers for 2 hours last night. Glad to be back.
I wanted to ask what problems if any that you folks have had with the Holly Sniper fr 4150 master kit?

I stopped into our local hot rod shop Kennys hot rods and spoke with them about the install. They have a large following and great reputation over the last couple of decades in town. There master tech warned me that the sniper has issues with Ford motors. He went on to say that the ecu in the bowl is to close to the distributor, It send wacky electronic waves to the ecu and makes lots of hickups. Often making the engine stutter and almost stall. Ive already purchased the fr4350 efi master kit and now Im bummed if I cant install it due to this manufacturing error. I already have the Msd 6al installed and it works great.

Hot rod shop recommends the Holly Terminator x stealth because the ecu is mounted under the dash. Thus solving the wave interference from the distributor and ecu.

To those who have installed the sniper to there 351c engines? please tell me how did it work out for you? I cant afford to do this install and then tear it out because it doesnt work?

Thank you in advance for all your help! I appreciate any and all help!
Rod
 
Thanks for the reply!
Im looking for reliability mostly but a bit better fuel economy or cheaper gas would be nice ( maybe vote in someone who gives a crap). LOL I get 6 mpg.
Currently I have a eldabrock performer 4v intake with a QFT carb, hooker headers, a little larger cam. Only 300 hp and 300 ft pds of torque. I drive it daily as weather permits. I restored the whole car so I show it as well.
Gears are 350 posi with a FMX tranny all are rebuilt. Engine has msd 6al electronic ignition.

I figured I was all set to install until I was told by Kennys rod shop to send it back.
 
Machattack,
MSD 6al ignition, one strike against you (high energy and magnetic pickup) a distributor with an optical sensor would be much better.
Specifically what alternator are you running (style and amp rating?.
electric cooling fans electrical rating ?.
air cleaner size and clearance to distributor, metal bottom & top or other?.
Having a ecu inside the car would be a plus.
Single plane or dual plane intake manifold ? efi is going to like a single plane better(air/fuel distribution will be better.
there are steps you can take before install to help with EMI/RFI.
All electrical terminations need to be plug and play, no splices, crimp connectors or anything of that sort,
Your exhaust system needs to be 100% leak free.
Before installing throttle body, physically (measure) each throttle body butterfly, front right to left and rear right to left and after minimum IAC has been established, check and sync front to rear ( this one almost got me on a very expensive crate motor install) Holley is aware of this issue but will not admit to it.
Oops, have a properly grounded hood and redundantly grounded exhaust system.
After that and a good tuner, its a crap shoot.
Boilermaster
 
300hp/300ftlb is a fairly mild build. 6MPG sounds like something else is already janked up.
You should be able to get double that around town and triple that on the highway, with a carb.

For EFI, there is a competitor to holley called aces. They sell kits like this, where the ECU mounts under the dash and it is cheaper than the holley. may be worth looking into if you aren't gonna take a huge hit on restocking fees on the holley.
 
Hello everyone,
Its been a while since ive been on the forum. Found myself reading questions and answers for 2 hours last night. Glad to be back.
I wanted to ask what problems if any that you folks have had with the Holly Sniper fr 4150 master kit?


Rod
Hi Rod, Like you I haven't been active on the site for a while, but I've been lurking in the background.

I have a Sniper and have had very few problems with it. Mine is on a 460 but I know a few of the members on here have them on their 351's. I originally had a Duraspark dizzy but have switched over to the Holley Hyperspark so I can control timing. I also have a MSD 6al. The main issues from all that I have read, and experience myself is emi/rfi, which in most cases is caused by a not taking the time to ensure that the Sniper wiring is as isolated from the rest of the electrical/ignition system as possible.

In my case, the car was running fine one day and the next day it wasn't. After thinking about what might have changed, I realized that the night before I had re-routed a few of the wires from the stater solenoid. While doing this I had the moved the power wire for the Sniper from the battery, crossing it directly over the wire going to the alternator which caused my emi issue. After moving it out of the way the car ran great again.

Below is a link of a post I did after installing mine and it has a link to some good info in it. Ignore the last section of it regarding the accelerator linkage.

https://7173mustangs.com/threads/holley-sniper-info-and-resources.40174/

Although there is some know issues with the Sniper, I wouldn't let what your mechanic is telling you discourage you from installing it. They work well and are worth the money.

Hope this helps
 
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I have the Holley Super Sniper feeding my 351C in the Rickster. It works just fine, and gives me a lot of information about what the engine is doing. I did have problems, initially, that were tracked to a bad fuel pump, and then a small exhaust leak that caused the air fuel ratio to show lean and resulting in the engine running very rich. (Exhaust leaks will really mess things up.) Once the fuel pump and exhaust leak were sorted out, the system ran like a top. Coming back from Ponies in the Smokies, it started running rough and missing occasionally. The data log revealed an injector problem. It was warrantied back to Holley and they repaired it and passed it with a clean bill of health.
Would I go with the Holley Sniper again? Yes, I would. It's a good system.

Now with that being said, if you want to stay with a carb, you should check out the Carb Cheater. https://thecarbcheater.com/ I've not used it, but I've heard good things about it.

Good luck, and whichever way you go, let us know how things work out for you.
 
Now with that being said, if you want to stay with a carb, you should check out the Carb Cheater. https://thecarbcheater.com/ I've not used it, but I've heard good things about it.
I have a carb cheater on one of mine. As a tuning aid, it is great. I do not like it for running in auto-tune mode to try and do on-the-fly adjustments.

My reason for saying that is mainly the speed at which it operates. It cannot slam the IAC valve closed fast. Therefore, if you have it in autotune mode and stomp on the gas, it may decide to open the valve up all the way. Then you lift your foot off the gas, shift gears, and get back on the gas. The carb cheater cannot react quickly to all that throttle input and varying engine loads.

Jets, vacuum, springs, O2 sensors, the ECU, and injectors can all react to varying engine conditions in milliseconds. The IAC valve is a snail by comparison.
 
Sniper 2 has the ecu on the side to help with rfi issues the mechanic talked about

I went one step further and went termX stealth 4150. The ecu is in the passenger footwell.

The spark box is hidden in the cowl. Coil is on a custom bracket off the AC compressor mount.

Display is on the steering column

I enlarged the hole the vacuum lines would have gone through the firewall and ran the ecu wires through it. Covered the opening with a sealsit grommet. I have classic auto air so no vacuum hoses needed.
 

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Not the same but very similar. I have the Fitech TBI unit. My runs very good. The main issue with any installation of these units is to not cross (or run parallel) the power and RPM pickup wires with others that could cause electromagnetic interference with the system. In my opinion, the distributor is too far from the TBI to be an issue. Just keep the plug wires and high amp wires away from the TBI wires. Better to use wires and plugs with resistance to reduce the chances of EMI. Also, use a relay to control the fuel pump instead of relying on the internal relay of the TBI - at least in the Fitech.
 
Not the same but very similar. I have the Fitech TBI unit. My runs very good. The main issue with any installation of these units is to not cross (or run parallel) the power and RPM pickup wires with others that could cause electromagnetic interference with the system. In my opinion, the distributor is too far from the TBI to be an issue. Just keep the plug wires and high amp wires away from the TBI wires. Better to use wires and plugs with resistance to reduce the chances of EMI. Also, use a relay to control the fuel pump instead of relying on the internal relay of the TBI - at least in the Fitech.
Ya I did add a constant current rated relay in the trunk with a cutoff switch for the fuel pump.

That way I can use the switch ti disable the car and also turn off the pump when I am programming or whatever work I am doing.
 
Hello everyone,
Its been a while since ive been on the forum. Found myself reading questions and answers for 2 hours last night. Glad to be back.
I wanted to ask what problems if any that you folks have had with the Holly Sniper fr 4150 master kit?

I stopped into our local hot rod shop Kennys hot rods and spoke with them about the install. They have a large following and great reputation over the last couple of decades in town. There master tech warned me that the sniper has issues with Ford motors. He went on to say that the ecu in the bowl is to close to the distributor, It send wacky electronic waves to the ecu and makes lots of hickups. Often making the engine stutter and almost stall. Ive already purchased the fr4350 efi master kit and now Im bummed if I cant install it due to this manufacturing error. I already have the Msd 6al installed and it works great.

Hot rod shop recommends the Holly Terminator x stealth because the ecu is mounted under the dash. Thus solving the wave interference from the distributor and ecu.

To those who have installed the sniper to there 351c engines? please tell me how did it work out for you? I cant afford to do this install and then tear it out because it doesnt work?

Thank you in advance for all your help! I appreciate any and all help!
Rod
A friend of mine installed a Sniper in his 67 Mustang on a fresh build 347 stroker. He had RF interference and he couldn’t track it down. He had the same issues you mentioned. After many frustrating hours and several stalls, one Holley tech had the solution. He had a Pertonix igniter in his oem distributor. The Pertonix was the cause of all the interference. He then installed a Holley distributor with a crank sync that was matched to the Sniper. Problem solved. With my 393C stroker build, I installed a Sniper with a Holley/MSD dual sync distributor and have no issues.
 
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A friend of mine installed a Sniper in his 67 Mustang on a fresh build 347 stroker. He had RF interference and he couldn’t track it down. He had the same issues you mentioned. After many frustrating hours and several stalls, one Holley tech had the solution. He had a Pertonix igniter in his oem distributor. The Pertonix was the cause of all the interference. He then installed a Holley distributor with a crank sync that was matched to the Sniper. Problem solved. Which my 393C stroker build, I installed a Sniper with a Holley/MSD dual sync distributor and have no issues.
Ya. I have the Holley dual sync on mine, too

Plugged into the EFI no adapters needed
 
Here is a video on how I ran my wiring. Hope it might help those who are planning on installing one. Please note that I have a 460 but really shouldn't make a difference. Remember to keep the Sniper wiring as isolated as possible from the rest of the car electrical/ignition system.

 

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