Hello. It will drop down to 400 RPM then climb 500 and then shoot to 900 and then come back sometimes two or three times then catch it self an idle just fine again. If you are idling at 2100 RPM (based on a default IAC Hold position of 30%) and your target idle speed is 900, then the ECU is not going to try to idle down. I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. (Do this while you are cranking.) Often, folks will say, "I did everything you said. I would start by datalogging the situation and seeing exactly what your learn table looks like in the area immediately around the tip-in. Will restart but only for a minute or so a couple of times then shuts down fuel delivery and will not restart. It felt like it was flooding out at low speed, low. 680-700.I can't find any reason other than it looses where it is in the firmware with Nothing against Holley's method but I need to keep things simple and I do that by eliminating the effect of the IAC entirely while getting the idle speed adjusted. That is likely just confusing the issue.Instead, choose whichever setup most resembles your camshaft and stick with that. Adding a wrap to the return spring on the shaft is one alternative to solving this. Good afternoon Chris, thanks for taking the time to help all of these folks that didn't purchase from you- myself included!The issue I seem to be having is at idle in both park/neutral and drive. :-DStill, I hate to leave someone hanging so I'll try to help. Thanks for your very detailed question! At 0% it shouldn't be sucking any air through that port, correct? I also raised idle at Park a bit with the idle screw. Also if I give it a Let Second--even in the HP and Dominator systems where a fuel pressure sensor can be dalogged and displayed, the fuel pressure is not fed back into the algorithm. I had a customer recently with a high idle problem that he eventually traced to pad plug on one of the vacuum ports. This will go a long way to improving your fuel map without manually adjusting the acceleration enrichment. Is this normal ? Going in the direction you did (higher) is going to reduce the acceleration fueling that the engine sees. I keep wondering how it was running so good with Hi Chris, I have a lean stumble on throttle tip in 2-3% tps taking off from a stop light the afr will go to 19afr and the engine will stumble for a split second. After talking to Holley tech, I replaced the factory regulator and problem solved.The regulator had what appeared to be a film or something almost clear embedded in some of the screen, maybe from factory or from install, but that was my issue.PS : this page and other forums have helped me a lot. Without it you are working in the dark. The timing can drift 0-30 degrees just due to the width of the rotor tip. Once you confirm the operation of your IAC then it's time to read my article on Solving RFI Problems. In the warm state IAC adjusted to a position of 2 to 10%. Holley Sniper IAC Problem 04-26-2018, 11:30 AM Hello. I called support line he said he would have to look into it and call back. Jump on board now! That is the only way to fly. This will tell us if the ECU thinks that it is in control of setting the idle or if it thinks that you are driving the engine speed with the pedal. :-). Well, it turns out that with the current firmware this throws the IAC control into a bit of confusion. So, this is what it takes to put a Sniper on a small-block Ford. Eventually the IAC will drop back to zero, I'll readjust it to 850 RPM & 2-9%, and then watch it steadily climb again. Its rare that you find someone that genuinely wants to help and see something work good, the information I have received from this page and Chris himself is top notch.1969 Dart GT 340 with a Holley Sniper, I purchased the Holley sniper from jegs wish I knew you sold them put on my truck got the IAC set haven't checked the -40 idle setting yet my problem is my headers are glowing red called Holley I think I got the worst person seemed to care less Afr is set at 12.8 for idle only thing I have changed I don't smell any fumes at idle someone said I could change the coolant temp enrichment but I don't know if it is rich or lean I figured since no smell it is lean any ideas would be appreciated thanks i have a fuel psi gauge reads 60 psi don't wanna melt my motor did not glow with a carburetor. I will a, Scott has been very helpful and informative on guiding me through the purchasing and installation of my terminator X max system. The only other thing I changed was accel enrich but whatever way I go doesn't seem to change anything unless I change it drastically. I hope everyone enjoys this v. Interesting question. If the engine will after the 4 seconds that the IAC kick drops off then it's not really going to help.At any rate, it costs you nothing to advance the ignition and see if that doesn't improve the idle, right? There are two ways to address this--you can let the system learn or you can manually adjust the acceleration enrichment. Holley Sniper IAC Surging???? So, if pressing the throttle is making it start, it's because you're flooded.Which is consistent with your rich idle condition comment, right? The RPM would increase for no reason. Fuel Prime Multiplier is primarily a benefit to throttle-body based EFI systems. The ticking is inline with the fuel pressure I feel squeezing both the fuel return & delivery lines (like a heartbeat). The second thing to realize is that even after you get it just right, you need to keep an eye on the IAC number and reset the idle if it gets outside the 2-8% range when idling when warm. Doesn't want to start, runs like crap. One additional wrap on the secondary coiled shaft spring is all that's necessary. idle at 1100 on the "stock" file it's better with street strip.The IAC counts will be at zero. I don't want to go on too long here but once you know if you're trying to add or remove fuel, there are a couple of ways to go. In some cases, you may only be able to put as little as 10 RPM between the hard idle and the target idle. I installed the Holley Sniper in my Chevelle this winter with a brand new BluePrint 496. It's the same one that Holley puts in their Sniper Master Kits and I've never heard anyone with anything but good things to say about it. No big deal, just time to re-adjust! 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. Hey Tommy, we've got at least one thing in common. Then you can take a close look at the IAC and see if it is opening. On a cold start it will idle at 750 everytime, But if its hot start it will jump upto 1600rpm for 2 seconds then come back to 750. I'm new to the efi thing and any help would be seriously appreciated. issue. Initial thought is timing but Im running a cd box and the ecu is not controlling and I did not physically change it during the install. If the connection is loose it will cause the system to shut fuel off because the signal telling the EFI the motor is turning stops (to prevent excess fuel from being dumped in the motor). It's hard to know what the previous owner did right versus wrong. Or ?I have put a fuel pressure gauge right at the inlet of the sniper and it is reading 60-64 psi. The engine might run hot but if the timing is right it should keep that heat in the engine--which is where the damage turns up. Tuning > Advanced > Adv Idle > IAC Startup This will let you know at a glance if something is going awry with the fuel pump. I keep doing that with the same result. Anyway I have a 327 sbc in a 1987 Monte SS with a T5 5 speed and 3:73 posi rear. The Sniper EFI remote IAC (Idle Air Control) and plug is designed to gain installation clearance on some Sniper EFI 2x4 installations. Um, no. If your mixture is too rich, it means there's too much fuel and not enough air. Since the load is more of a wave that increases the most initially and then decreases again, the ECU is doing really well to get the idle under control in only two or three over/under shots as you describe.You don't mention if you have your Sniper ECU controlling timing. It could be, but that seems unlikely.Instead, you need to look at the basics. Reply Quote. An undersized or partially plugged fuel filter is a classic EFI installation mistake. Two months fighting, cursing, not getting any help from Holley OR the forum, and a stupid little tin plate. when things aren't working and this provides just that. As I have it set right now, my idle at park is in the high 700s and my desired idle in gear is set at about 700 cold (80 degrees) and gradually lowers to 590 once engine temp reaches 160 degrees. Give that a go and see if you don't make some progress! and when I close the IAC's hole with his finger, the engine is normal.The data on the touch screen I see are:AFR, A / F = 35.6 Is this an issue to worry about? I think that your Sniper system is working fine but would definitely check ouf the fuel pump. I presume your idle speed table doesn't increase at 200 degrees? It really takes a lot of throttle tip-ins before you get anywhere near "learned" in this part of the fuel map.Based on your description, it sounds like you have a lean stumble. We do that but most places don't. (Don't drive and watch--get a helper!) When I covered the IAC with my finger, the RPM dropped so low it stalled. I started with right after I first adjusted for 2% IAC and took pics about every 30 seconds over about 2 minutes. Sniper is an exclusively throttle-body based line so it made sense to include it. Holley have given a new unit. THANK YOU for the "First--Check Your Idle Speed Curve Setting!" If you don't have a working coolant temperature sensor then it will never bring the idle speed down. If you have somehow overlooked this, start here: Holley Idle Speed Adjustment Instructions: Once the engine is up to operating temperature, the idle speed can be set to what was configured in the Wizard. Any help would b great. Key, I believe, in this success is solid connections, resistance-free signal and ground paths, and solid RFI rejection. Once you so this, and after you have your CAN-to-USB harness attached to your laptop with the Sniper software, you can see precisely the cells where the system is operating when the bog occurs. When you key on, you will hear three distinct sounds: The ECU initializing the IAC, the fuel pump priming, and the injectors firing their prime shot. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. back to trying to zero down an idle. I recommend you have a look:https://www.efisystempro.com/efi-pro-hangout/holley-sniper-efi-instruction/solving-sniper-rfi-problems, I recently purchased your fixed linkage to open primaries first and the throttle linkage extender to also get a smoother pedal. I managed to get the IAC down to around 0% - 8%is this good? This page was generated at 12:25 AM. Camshaft is M-6250-B303 .480 lift intake & exhaust, duration at .050 is 224 degrees for intake & exhaust. Advanced throttle body injection systems capable of transmission control and more. And since they really had an insanely-tight monetary and real estate budget in the Sniper EFI System, it is unlikely that the added something that wasn't absolutely necessary--and then forgot to use it..And you are spot on about the little Earl's gauge with optional -6 AN port. I appreciate the help youve given to everyone as it continually helps me! have the system learn the higher speeds? Confirm the placement of all wiring, ensure that the WBO2 sensor is positioned properly, etc. When I start the motor I have to push on the accelerator pedal for the motor to start. You have to remove all hoses in order to debug the problem. Thank you so much for your follow-up. Hello Chris. When you set the Static Timing to 15, what did you read with the timing light? I'll have to check again tomorrow. Of the two options, I generally recommend the self-learn. If I rev the engine a couple times in neutral it will finally return to idle & usually will not do it again for the rest of my trip. Handheld shows plenty of fuel so I dought it's an issue there. When I shut it off then start it I'd really appreciate some help. Worst case you'll have a spare on hand, and if the TPS is faulty you will have solved the mystery. have noticed on the hand held is that Air/fuel Ratio rises to 20 +/- A/F and the That disappears as soon as the throttle is pressed and then you immediately revert to your timing table.You can certainly use the compressor to initate the IAC Kick, but remember that this is just a temporary idle boost to ensure that the engine doesn't die when the AC is first turned on. The team at EFI pro are some of the best I have ever dealt with when coming to ordering parts or having the knowledge to answer any question you may have. It is how the engineers allow you to clear a flood condition when you detect it. shut truck off. For the first couple of drives it was running well, Sniper EFI was working exactly as advertised. So if you are trying to achieve a stoichiometric mixture in ethanol (which is achieved at an AFR of 9.0:1) then you should continue to target 14.7:1 since that is what will be displayed. It is always best to get the base map as close as possible before adding acceleration enrichment. Don't try to correct for the fuel. 30 minutes later CTS reads 161, start engine Idle is jumping from 450 (almost stall) to 1500, IAC is jumping all over 10 90. You're going to have to get this fixed or it's going to cause even more problems than the high idle. nothing stays steady. Until the engine starts, the throttle only has one purpose: To detect you pressing it to 60%, at which point it shuts off the fuel injectors. If the TPS is 1% or below then the air is coming from somewhere else. There's still a very small amount of airflow that squeezes past a closed IAC valve; it's that venturi like sound you're hearing. A simple remove & clean will remedy this . This curve turns the idle speed down as the engine warms. I looking for your expert opinion. We're having trouble with a Ford Maverick 302 V8, using ethanol. Once you have done this the challenge is to create a datalog that includes the ":snap" you describe. That is the first thing you must find. The noise is definitely coming OUT of the throttle body. It's all part of the adventure! In the context of the Sniper the AFR that is being displayed is the AFR of ethanol-free gasoline based on the lambda that is being read by the AFR. This is normally used as an A/C idle-up circuit. knowledge with the sniper efi setup. Use the idle speed screw to set the idle at a comfortable warm-up speed. I recently had IAC issues identical to what you describe. It is a common one. Thanks for any help. Replacement Idle Air Control (IAC) Motor for Sniper EFI TBI Systems, Sniper 90/92/102mm Throttle Bodies, Terminator TBI, Avenger 4bbl TBI, HP 4bbl TBI, Commander 950 & Digital Pro-Jection Systems. It might be necessary to insulate or re-route your fuel lines if this can't be solved any other way. Yes, it will talk to you--but not with words. He said they have been having an issue with these lately. Then why don't you Get On The List for Emails Straight From Our Pro? I would not expect that an electric fan would create a noticeable load on the engine but if it did then you'd want to set the idle screw when the fan was not running. Intermittent stalling usually points to radio frequency or electro-magnetic intereference (RFI/EMI). I'm running a 408 sbc. Either the Walbro pumps you are getting are not genuine (lots of forgeries being sold) or else you have something that is killing them. On EFI systems such as Holley's Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. I will turn it up some. While this video is not meant for the Sniper EFI user it does provide a great overview of how your ethanol tuning adjustments must be made not only to the base fuel map but to the other configuration settings. Switch power to the Sniper on and crank the engine. idles good, runs amazing. At that point the tps is pretty high, then shut the ignition off, pull the tape restart the engine and idle goes into hold mode and idle is through the roof. hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I I have been able to get it pretty check out the. Get On The List for Emails Straight From Our Pro? That, on top of your air leak, is allowing the engine to idle at 2400 RPM. The "PC Text" indicates what will be shown on the PC/Laptop data monitor or data logger. Some have suggested the gasket might cause it but I've never heard of anyone fixing the whistle by adjusting the gasket (and many have tried. Technically it is a warranty-voiding maneuver so proceed at your own risk. Its timed to 36 degrees. You can disable the idle spark control at the locations below. When I turn the key on I can hear it prime, but I don't think im getting enough fuel. Any suggestions? P.S. Contact whomever sold you your system or Holley directly. You just need to go back through the IAC adjustment procedure now that idle timing control is enabled. Can the return line be an issue?So far this sounds like an ideal setup.>I have had 2 faulty gpa-4 255 walbro pumps go bad. It didnt do this with the carb on it. Thanks, That is an strange situation. You advise would be greatly appreciated. We're never going to fill up your email box with nonsense. If you haven't confirmed that they it is worth checking. I have seen a couple of videos on you tube of the same issue but they don't seem to have found the cure.I hope it is not a computer problem as I have already replaced the entire system because of another problem. It'll start & run till it's warm, then when I try setting the IAC every time, I try getting it between the 2 & 8% it quits. I installed the Sniper on my 1978 Ford F-100 with a small block When I am coming to a stop, the rpms will hang at 1200-1500 rpms. If you find that the IAC is more than 8 percent, repeat this process and instead of shooting for 50 RPM below your target make it only 40 RPM below the target idle speed. The problem was RF interferance . That is certainly not normal! Im not sure what its doing, have messed with after start fuel, fuel at cranking. If I'm driving along and pull up to a light and leave it in gear it idles just fine but it seems not to be able to compensate if I put it in neutral and then back and drive. I know this is old, but I bought and installed a Sniper kit in 9/18. All times are GMT-6. Look over all of your vacuum lines and fittings. I tried adjusting my IAC up to 10deg in both directions with no change. So, clearly, the "No" answer is wrong. I also noted that after some time, I could change those values as I saw fit. If the IAC number is increased during this high idle, review the points about high idle from tuning issues. If I go any more it will ping. I have one customer who is having some similar issues and his AFR is down at 9.6:1 when it won't start. The person I bought it from said he never could get it to run for more than a few seconds. Please help. Is that normal? Your suggestion to remove the PCV valve is just for diagnosis purposes, right? When you first posted this I had no idea how to respond. Enjoy your Sniper! Then, the next time I cranked it, the idle went high and won't come down!" But as you see from the recent revision I did above you seem to be having a fixable issue. My car will now start when its cold, but after about 30 seconds the idle drops down and begins to run like crap. It turns out that some of the Snipers are shipping with the minus 40-degree setting drastically lower, as shown in the following image. Solution #1 Put car in gear take off and the engine runs GREAT, no issues drive for 10minutes take car out of gear and engine idles correctly IAC between 2 and 5 Solution #2 Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. It then started working normally again. I had a customer who struggled to understand that. Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to Please advise. Now that you've installed at least four Snipers it is going to be imperative that you learn to create and read datalogs. Keep in mind that at 60 miles the port that goes right on the inlet of your Sniper and makes installation a breeze.If your fuel pressure is solid at about 60 PSI then you should start looking at But I am having troubles.When stepping on the accelerator slightly with idling, it will be 2000 RPM all the time. Yes, the sound coming out of your Sniper throttle body is a pulsation from the fuel pump that is pulsing the mechanical fuel pressure regulator. Hello The IAC is hanging open and not really at 0. Chris, I recently installed my Sniper and have an intermittent idle problem. Ensure there isn't a vacuum leak causing the IAC Position to drop to 0%. I am at the point where I almost insist that every Sniper EFI System owner purchase one of these. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. I watched the butterflies start to open at about 35 on TPS. But I think it is safe to say that you are now at a point were some manual tuning is a good idea. Full product line and accessories at excellent pricing. Holley documentation and videos didn't work and the $300 I paid for "expert" tuning didn't work either. Get that thing installed and you're going to know a whole lot more about what's going on. close to idle with the IAC between 2% & 12%. Once you know that then you can work on those problems. Since it is unlikely that anything else changed it is most likely the IAC is problematic or the butterflies are not shut all the way. It only comes back to normal if I turn the engine off and on again. If you use your handheld to go here: That is the IAC hold position. Since that has long been corrected we have moved that information to the bottom of the article.). Well you were right air was entering from another source. So I had my Idle set up perfect, with idle timing control off and engine hot the IAC was right at 2-4%. There's nothing wrong with manual tuning, but at this point that is just compensating for an inadequate fuel map. It appears that I could now use the dongle and a laptop to custom tune for idle issues if needed. Capability Range: Advanced I have it set at 650 and it idles anywhere from 590 to 700. Short drives is fine then it'll One of the best Ive seen so far. That could be a problem with the TPS or it could be some sort of throttle linkage issue. If not then I think you are going to find that this will solve much of your problem. The throttle plates are misaligned. Thanks for the great question! I chased that gremlin for about three weeks and was convinced I had a bad throttle cable. The Tech Tips and discussions are also great! Target AFR at idle is 13.8%. If the minus 40 degree setting is lower than the setting to the right, simply move it up so that it looks something like this: The folks who have tried this have found that their idle speed control behaves much more as they expect. When you have the issue you should disconnect all hoses and plug the ports on the Sniper. I never had a problem with this. Across the board, all of our customers say how impressed they were that it started and ran right out of the box just by following the simple installation instructions. If more info is needed just ask. i would have been happy to answer there. The last pic is with the car in Drive. Running a bbc with coil - my timing is perfect. I'm going to jump out on a limb here and say you either don't have adequate fuel flow or pressure. After a complete cool down it will do the same thing. Capability Range: Professional A question I cannot get a 100% answer on is can you piggy back off the Sniper EFI TPS for an electronic transmission? Sometimes it sounds like it wants to crank at the start but runs out of gas. If you look down and your TPS is 2% then either your throttle is stuck slightly open (which itself will cause the idle-up) or RFI riding on the TPS signal has caused the ECU to see the throttle as open and, as a result, open the IAC to the hold position. You can find those settings here: Handheld: Tuning > Advanced > Advanced Idle > Rampdown, Software: Idle > IAC Settings > IAC Ramp Down. Next, clean the IAC and all related parts with brake cleaner. First, recognize that the amount below your target where you set the hard idle will be different on different engines. The 5-6 times it has happened now have been after the car has been running for at least 20 minutes. Some have suggested mis-setting sets the idle speed at 850 RPM but I suspect it is not a fixed number but rather a delta of about 300 RPM above the target. What should I be looking at to calm this down? sniper Installation If you're installing a Sniper EFI system and almost ready to crank it over for the first time, this is the video for you! Just add 5 or 10 degrees of advance and see if it doesn't idle better. carburetor setup, but it does blow when I can't jump on the highway like I use What could be the cause? Software: Idle > IAC Settings > Idle Spark, Handheld: Tuning > Advanced > Advanced Idle > Idle Spark, After completing this 10-step process, if the temperature displayed on the handheld is still above 160 degrees the engine should go right to it's target.