Sniper EFI Idle Tuning

[@jeremyellis88]

One problem people have been having is the A/C fan control is set at 50% out the box. Causing odd surging issues. I set mine to 0% fixed the problem. It's not a issue for some reason if you do have A/C and only if you don't.

[@ringgap]

If you have an automatic transmission: Start by putting a piece of duct tape over your IAC hole on the top your TB and adjust the idle screw until the idle is at 740rpm at about 14.4afr. Restart ignition. Once the car runs fine without the iac take the tape off. Shift from park to drive with your left foot on the brake and you right foot on the throttle to blip as the engine starts to stall. IAC will hit 20% and slow to 12%. Back and forth P to D until the IAC learns. Stall test for no more than 5 seconds to build more learn data.

[@ringgap]

AEM in their 30-4110 PDF states that running the LSU 4.9 at less than 0.95 lambda shortens its life. Should we be running these Snipers at anything less that 14:1 and expecting longevity?? AEM: IMPORTANT Notes - PLEASE READ The sensor contains a ceramic module and should not be subject to mechanical or thermal shock or it may be damaged. The sensor is not designed for operation on leaded fuels, doing so will dramatically shorten sensor life. Long term running in the rich region (Lambda < 0.95) will shorten sensor life. High exhaust temperatures (over 850C) will shorten sensor life. Engine oil consumption at a rate greater than 1 quart per 1,000 miles will shorten sensor life. With the UEGO Sensor installed, do not run the engine without power applied to the gauge.

[@cfmechanic]

​@Alan Conner well sir I have been thru about 8 or more 02 sensors over last 4 maybe 5 years. The one I have now has lasted over a year the trick to keeping it alive was moving it 6 inches long further downstream

[@Coryiwan13]

Did this actually work? I’m having the same issue with mine. Idles great but dies when shifting into drive. Have to bump the gas to help it not die.

[@jivepatrol6833]

Good video and methodology. I am retired OEM engineer with an extensive background in engine control systems. I have to work on a friend of a friend's Sniper system that won't run properly. I am going to read the instructions AND watch all of these videos. Thanks

[@jwnewman75]

I never saw these tips in the instructions?

[@jakespeed63]

Good basic info New customer with 455 Pontiac Firebird and Sniper EFI. Trying to educate myself on this setup Will definitely look into more advanced videos. More used to working on either modern vehicles or carburetors. Thanks

[@paulleonardo4906]

I adjusted the IAC using this video to about 5%. I had been having a problem with stalling when coming to a stop. I raised the idle to 750 from 650 and thought that solved it but I didn't. Then I tried adjusting the IAC and didn't even make it around the block. While accelerating the engine sounded awful and seemed like it was running rich. It stalled and was hard to start and smoked a bit when it finally started, and the engine was barely staying running.

[@theunderdawg]

Did you ever figure it out

[@hughjanus3235]

I'll bet you have (or had) a loose connection on one of the injectors. I had the same rich condition and rough running myself. Just fixed it - found one injector plug had rattled out. Sorted that out and the engine starts from dead cold just like it should now.

[@paulleonardo4906]

@hughjanus3235 thanks for the tip, I'm going to look Into this. I haven't solved this problem yet. Thought the problem was too small of an alternator, so I installed a 150 amp powermaster unit. Still running rich though, I hope it's as simple as a loose connection.

[@juice2620]

@@paulleonardo4906 Leaking manifold or header gaskets? That'll cause it to run rich too. Also the IAC should be adjusted between 8-12%

[@paulleonardo4906]

The alternator on the truck was a factory 55 amp DELCO. We determined this was insufficient for the EFI system. Never ended up being able to fix the unit, even after sending it to Holley for repair. We ended up needing to replace the whole unit, but now with a brand new Powermaster 140amp alternator the truck is running fantastic.

[@anthonymarkgriesehop2198]

Shield the units better! To many have RFI issues. Plates are needed between the units and the distributor!

[@Wilson_Racing]

They dont include a plate with the Hyperspark kit

[@jeffhall8282]

seems like alot of problems occur when timing control is applied to system.I installed the sniper on a big block chevy ,only has hei and an msd for ignition and it idles and runs perfect,simple sometimes is better.

[@Roy-ns7yy]

Great video. It was very helpful !!!

[@hunter37334]

My truck idles fine when its hot. It WON'T keep running without throttle assistance until it reaches 165 and the fuel loop closes. What to do?

[@79series]

Is there any Holley sniper efi videos on flat spots when flooring the accelerator flat from traffic lights causing flat spots.

[@knuckle47]

Have you re-checked your timing….found out mine actually handles 3* higher than factory setting and runs very well

[@davejalenderki]

Thank you for sharing the video. It was very informative.

[@captainsmate5770]

Hello. I have the sniper on my sbf 331. I have a problem with the way it accelerates the pedal seems to be tough to press and once I get it to move if pops loosing and the car lunges forward .the linkage and everything seems fine nice and smooth. no fun to drive I see a lot of videos on here about the progressive linkage where the secondaries open up a little later is that what I need to do or is it there adjustment that will correct that problem ? I can't imagine everyone that buys a sniper has to change the linkage right away

[@gmann5109]

I have the SAME issue!! What do we do???

[@captainsmate5770]

So here is my fix.it runs great now..so that little progressive linkage is no good secondaries open way to late 40% is no good missing to much range.what I did was straighten the original linkage piece just slightly so they open at around 14%..then go in an tell computer new range..also had adjusted secondary spring so it's not so aggressive.

[@cfmechanic]

Throttle lever extension is solution for stiff tip in

[@alvanmeter]

So I disable the idle spark and cycled and got the IAC back down to 5 but after turning the idle spark back on and cycling it’s up to 30. Is this part of Hyperspark still learning and it will drop down? Thx in advance.

[@cfmechanic]

Hyperspark doesn't learn only fuel learns

[@gayanimaduneththi8199]

Can i use this sniper EFI systerm for my Daewoo racer 1994 car?

[@code3k5]

Had the idle problem with mine, repeated this process, it helped but when I give it full throttle while driving the IAC stays 20% and idle increases 200rpm until I pull over and shut off the ignition and restart. Then it resets and runs fine again... maddening.

[@MikeBaxterABC]

I've been looking fr a video on how to set tjr IAC on Sniper 2 .. the set u is different. for example On the Sniper 2, There are two Adjustments screws with green springs around them. I really want to know what each screw adjusts? Like the front one (towards the front of the turck) adjusts _____ ? And the rear most one is for adjusting the _____________________?

[@MikeBaxterABC]

Just for the record I learned the FRONT SCREW (the onne on an angle ) is the "Primary Idle Adjusting Screw"

[@corygoodman]

Is it recommended that the old variable PCV valve be replaced with a fixed one? I've seen a few posts about the older style opening, adding more air and creating a lean warning on the handheld.

[@musclecars4635]

How do I troubleshoot my Sniper on my 528 Hemi to diagnose why the engine stalls out (lack of fuel?) while driving then goes back to normal? Still trying to find a local mechanic who knows how to use the Sniper.

[@68bry]

Add dielectric grease inside the distributor cap? Where exactly do I put it? I've put grease inside both ends of my spark plug boots, but never heard of putting it inside the cap.

[@V8N8T]

Not inside the cap, you can put some on the terminal or the boot of the plug wire that plugs on your cap

[@fadamec]

how did you get the tach (RPM) gauge in the middle of the 3.5 display to only read up to 5000 RPS''s. I have been trying to figure that one out and take mine off the 20000 RPM range?

[@charleslum2438]

Set your rev limiters and tach will compensate.

[@marineengineer13]

Here's a question mine idles around 700, and I set the iac to 3 but it will jump to 5-7 reving it 50rpm then comes back shits steady at 3 for few minutes. I verified no leaks new spark plugs and wires

[@edgarddorta6650]

Can someone help me? I have an engine that must be at 1200 rpm. The percentage of the IAC would depend on the revolution that the engine needs?

[@gmannfram8682]

I have a 68 chevy elcamino and i am thinking about going to this system and this guy really knows his stuff. The only thing I am wondering is about the cold start? They usually have a cold start injector right? what happens here to make cold start possible? Thanks

[@BryanBurch]

Just installed mine last weekend, fired it up at 18degF yesterday morning and it fired like a new car

[@BryanBurch]

Also, 69 Olds 442, 400ci

[@sethpayment]

While this was 2 years ago this got asked... To the original poster: Most EFI units built after 1990 didn't use a cold start injector... The Bosch CSI units used a cold start injector as well as a few of the obd1 Toyotas utilized 5:48 a cold start injector for extremely cold conditions in the case of a 3.0l Toyota V-6... But if you look at theory of operation on the cold start injector on that engine it is used for temperatures below 20°F... The Bosch CSI systemt used one because they fuel distributor which mechanically controls AFR with a flapper valve in the intake system that moves the pintel inside the fuel distributor... The flapper valve was similar to a vane style mass air flow sensor...

[@207shenanigans]

So, my sniper efi just started reading SlOW! On the afr reading. What does that mean? How do I fix this? Nothing been changed and it read fine before

[@bennieblanco2607]

My IAc is at 67% and turning the screw has no effect on my percentage going up or down. Any suggestions?

[@jacobgonzalez1756]

Did you figure it out? Their tech support is real bad. I can’t get mine to idle higher

[@millmilk2566]

What if I run into a problem where I dont hear the fuel pump and the monitor says no data

[@marx769]

Thank you!! 🙏

[@morganwadsworth9275]

I’m curious if anyone can help me out. I’m trying to figure out how the Sniper learns…for example, I assumed that each drive would have the Sniper learning and that eventually the learn percentage would reach 100%. Mine seems to start from about 8% at each start and then only ever gets to 28% at its highest learn rate. Is anyone ever seeing 100% on their installs? Or does it start from scratch at each start by design? I’m running the Sniper BBD on an 84 AMC Eagle Wagon if that helps. It’s the CJ7 kit that Holley sells. Cheers!

[@gragumilo]

Hi! You want that number to be as low as possible. It actually means the amount of correction your sniper is making to you fuel table, so the lower the better. If you sniper has learned "100%" as you mention, your learning graph would read 0%... But it really isn't that simple. Drive around for a couple of weeks, in all conditions, then remember to transfer the learn table to the fuel table. Do it again and you should see lower numbers on the learn table.

[@morganwadsworth9275]

Oh wow…thanks. I was thinking about it completely backwards. Thanks for making it make sense for me. Now off to plan a new fuel tank and in tank pump to get rid of the angry mosquito sound of the external fuel pump. Cheers!

[@BAHRacingTeam]

Did everything correct, ran like a champ for weeks, now it throws the idle to 3500. Can’t find the problem. About to go back to the trusty carburetor

[@rsrxadwat33]

Hi friends, I have a problem, after 30minutes run in the road the AFR-AF parameter up to 35 and the car are shutdown, Im wait 30 minutes and continue runs perfect but after 15 minutus the same fail occur again😰

[@TheDeezelsmoke]

Make sure you don't have any exhaust leaks, or leaks around the exhaust O2 sensor.

[@edgarces2827]

Hi Rolando. I have this same problem. Did your resolve the issue? I hope you did and I would really appreciate it very much to know how you got it fixed. My mechanic cannot find the problem. Thank you.

[@TCB2023.]

Love you bro!

[@hodsonmotors]

Should the IAC position % be at 5-6% while in park or in gear?

[@rlovell383]

park

[@mosesandres3385]

What is the IAC suppose to be at while in gear?

[@HolleyPerformance]

It varies depending on the combination but you should expect something in the 40-60 range

[@mosesandres3385]

@@HolleyPerformance ok thanks and after how many miles with the sniper unit stop learning ? When on the freeway at about 3100 rpms my car will have a jump in AFR then go back down to what it's set for. (Street/strip) i have put about 200 miles on it.

[@k-laus9435]

What Holley doesn’t tell you is that the PCV valve with the ball in it is a complete nightmare for tuning. Calling tech support they recommend that you use an adjustable style like a Wagner. I finally ditched the setup for a motion raceworks catch can with the adapters for SBC valve covers. Fought this for weeks with multiple calls to tech support.

[@thinetaco3722]

I read to get a fixed orifice pcv valve, also where is the pcv supposed to be hooked up to, I thought it was for the front plug, but in the video they have their routed to the back, would that make a difference?

[@k-laus9435]

@@thinetaco3722 it doesn’t matter where you put the pcv setup. Usually goes towards the back for convenience to the back of the carb. It will vent positive pressure out of any hole in a valve cover. Wagner is a adjustable pcv valve that you can adjust using a vacuum gauge then lock it in.

[@joelrushin4363]

If order a sniper stealth will it control timing on a ls

[@HolleyPerformance]

No, sniper will not control an LS ignition system. We recommend a terminator X system for that application.

[@joelrushin4363]

@@HolleyPerformance msd box terminatior stealth

[@BGOESWILD]

Iac is at 80% start up. Goes to 100% when running. Any help much appreciated.

[@HolleyPerformance]

Open up your throttle blades using the idle speed screw!

[@joelodegaard9964]

my wont run when hot how do you fix that with computer speak

[@arizonarider6998]

Tried all this and that IAC is never set . 😡

[@TheReinoPaasonen]

Thank you for great info!

[@teh1955]

Are those instructions available in text version? Would like to have a copy of the transcript.

[@huseinparsa6796]

What is the problem if there is noise? (with using old wire and spark plugs ....)

[@cfmechanic]

I always feel like i get deja vu is this a re run. Man listen to that sniper sucker is loud when u get close I have always assumed it was my valve train but nope it's the sniper injectors.

[@jtepps5289]

Same does yours make a super loud sucking noise when its running i didnt think it would be as loud as it is

[@tylake3246]

JT Epps yep

[@cfmechanic]

​@@jtepps5289 a whistle noise can be had if you don't use 4 hole spaer

[@kingkire1556]

@@cfmechanic a 4 hole what?

[@gabyrossi8895]

Is there any possibility to turn the spanish subtitles on?

[@charliejamz.]

🌮

[@Therealkevink]

Can we at least sync the audio with video??

[@ThatTurboDakota]

Charging system does look like its working

[@mustangmatt64]

This car has a generator on it as did most 64 Mustangs. just above idle the generator starts charging better.

[@LoneWolfSnowplowing]

no, no it doesn't.

[@jimalldredge8691]

If it works right you shouldnt need to tune it. Beware of products that require " tuning " so if it dosent work right they can blame you.

[@LoneWolfSnowplowing]

tell us you have no clue without saying you have no clue

[@b.c4066]

All efi, hell even carburetors require tuning. It's not the product fault that you do not have a basic understanding of internal combustion engines, or how to make one run. Brand new cars have computers that work right.. after hundreds of hours of calibration for the engine/vehicle platform.

[@azeon9684]

I don’t understand the lingo

[@jasonlawley4577]

Video did not help. IAC is still all over the place, and so is the idle. Runs so rich that there is not a mosquito in a 5 mile radius

[@TheDeezelsmoke]

Sounds like you have an intake vacuum leak

[@bigbadbrad1100]

Dang, I wish you were my neighbor.😁

[@poormanprinting7837]

I'm having the same problem I believe you right there's a vacuum leak somewhere I need to find it

[@ozjado]

Haha anyone too good for instructions has no business playing with this stuff

[@chainsawcharl1e677]

Holley Sniper is junk. It stalls at every intersection. It is ruining my rebuilt starter, my rebuilt Chevy L32 3.4L engine, and the new battery on my 1986 Jeep Comanche. I will soon be a pedestrian.

[@jimalldredge8691]

Thought about getting one but all i hear is they never run right. Hollys putting out trash. Just like elderbrock not jetting their carbs for the proper elevation. Cant wait for electric cars . Then these crooks will be out of buisness.

[@b.c4066]

So you don't know how to tune.