If the vendor from whom you bought the system is coming up blank on ideas then don't hesitate to contact Holley's outstanding tech support department directly at 866-464-6553. Bolt-on carburetor style EFI for your classic car or truck. I've been trying to correct that 1% small issue/annoyance. Yes its at 95lbs, needless to say he promised a new regulator would be in the applies here because it is so important to realize that just because the IAC I recently detached the TP sensor from the side of the sniper to physically move it and it still would struggle to get to 0%. I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. Changing the rpm curve and target rpm has no effect. datsun sniper efi Holley RetroBright This 1974 Datsun 620 Bulletside Cruises With The Help Of Sniper EFI Bradley Iger 01/13/2023 features Latest News sweepstakes 2023 Hemi Engine Sweepstakes Gen III Hemi Enter To Win Holley's 2023 Hemi Engine Sweepstakes For Your Chance To Win A 600+ Horsepower 392 Stroker! Only show this user . Anyway I have a 327 sbc in a 1987 Monte SS with a T5 5 speed and 3:73 posi rear. Good luck! Though it started and ran good, it was dumping fuel and would not lean out to AFR set points. Does this seem reasonable and how hard will it be to get the idle and off-idle performance correct? When I covered the IAC with my finger, the RPM dropped so low it stalled. I think I figured some of my problems outI'll try to explain. 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 Honestly, I've never seen this happen but if the butterflies were misaligned on the shafts it could allow too much air to enter. 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. You advise would be greatly appreciated. Contact whomever sold you your system or Holley directly. Now I have most of the bugs worked out it runs fine on the highway and around town it's just the idle. This is a mighty big subject for a blog post reply, I should probably start doing some videos on this. I do know that the reference angle is 57.5, the inductive delay says 100.0. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. Relatively new Sniper EFI install on a '69 Mustang 302. If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. ?I never had my Carb Cold start RPM any higher then 1600 RPM.THANK YOU. See these. They tell you to ask call Holley. Price Point: $$, Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. Does anyone have photos of this additional return spring they installed? They are prone to be inaccurate. The answer will divide the possible sources of additional air into two, greatly simplifying the problem.If the IAC number has not increased, then review the article above regarding high idle from a vacuum leak or high idle from sticking linkage. Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. and if you do run into any problems then, yes, the plethora of tunability adjustments available through either the handheld or the Sniper Software will certainly be enough to get you right where you need to be! I did check for the lightning under the hood but all was well. And increasing your idle via the idle screw was also a good idea, because that will lower your amount of IAC that is necessary to keep your engine at the target idle speed. Intermittent stalling usually points to radio frequency or electro-magnetic intereference (RFI/EMI). Hello Chris. If you complete the process and find that the IAC is less than 2% at idle, repeat the process and use the set screw to make the RPM about 60 RPM below the target. Hello The fuel pressure regulator in the Sniper is fairly simple and not prone to failure, as far as I know. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. The IAC should display a 2-8% to bring the idle up to the actual target. >I'm using russell hi pressure gas line to feed the gas up to the sniper and using the stock steel gas line that use to be the feed line for the carb to return the gas to the tank. Thanks again. This curve turns the idle speed down as the engine warms. That is the only way to fly. The Sniper EFI remote IAC (Idle Air Control) and plug is designed to gain installation clearance on some Sniper EFI 2x4 installations. It could be, but that seems unlikely.Instead, you need to look at the basics. Please help. I've read that a spacer with 4 individual holes will solve this, but after I installed the progressive linkage the noise went away!! Only in the unlikely event that your engine simply won't run well enough to drive and self-learn should you consider tweaking anything inside of the first several hundred miles. In this short video you learn to replace the IAC. Have you checked your fuel filter and made sure it's not plugged?If both of these are okay you're going to have to find a way to monitor your fuel pressure while under load. 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. holley efi. Comp. If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. Strangely, what I've seen is that it idles too lean as the injectors are effectively shut off.Thanks again for the follow-up and glad to hear that everything is working well now. If the solutions suggested above are not working then you need to review my article on IAC Testing Procedures. If you haven't installed a The fuel pump is mounted under rocker panel as low as possible and far away from any heat. It is a common one. 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. Find a lower price anywhere and we'll beat it by 5%! Do please let us know what you find out! That changes almost instantly as the engine revs.Since the learning algorithm requires some time exposure to a certain condition to make larger changes, that half-second makes only the smallest impact. This was an issue in the earliest version of the Sniper firmware. My car will not idle right until it gets to around 130 -140 degrees. And the rather cavalier "Absolutely!" Repeat until that stumble goes away, and then try a bit more throttle. I drove it a bunch more yesterday afternoon/evening and the same thing happened several times. Every time though I can turn the car off and restart and it settles at 850 with IAC 2-4.The thing that has me puzzled is how the with the only difference in condition of the car being the restart, the idle is "fixed"Any clues on where to look next please let me know. But if the idle is a little bit higher then it doesn't have to jump quite as much in response to the load, and tends to react a little bit more smoothly. If your TPS is at zero and your IAC is at some random number above 8% (but not exactly 30%) then for some reason your engine has not met the conditions to ramp down to target idle. I have replaced the IAC motor and the problem remains. :-). This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. I have seen this become blocked with debris / dirt in the fuel system and cause a high fuel pressure condition . If you drop it too far the engine will stumble or stall when coming off the throttle with the car out of gear, so you'll know when you've gone too far. Featured Products EFI - Fuel Injection $2.59 - $6,499.95 2179 Products View Parts Sensors The latest was changing the power brake booster.Today I drove it to work and no issues at all. I have a 406SBC that does most everything right with this sniper setup. The warmer the motor, the higher the idle will be at this point. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds We've already tried adjusting the Acceleration Enrichment chart in all ways, going up and down, RoC Blanking, everything, it has no effect. Your issues are likely related to one of these two things. Should I just disable idle timing control? Just thought I'd ask as there isn't a lot of info out there. Coming home from work today it was much warmer and took a little longer due to traffic. Okay, try my method. I installed a sniper efi system on my 1969 Camaro. Does that make sense to you?
Top 10 Sniper EFI Installation Tips from Holley's Tom Kise The IAC going to 30 is normal. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. My issue is that the TP% will not reset with key cycle and its idleing at 9% TP. I chased that gremlin for about three weeks and was convinced I had a bad throttle cable. Fuel Prime Multiplier is primarily a benefit to throttle-body based EFI systems. I would gladly engage with you to solve this but ultimately you are going to need to go through whomever you purchased the system if a warranty return is in order. It's pretty hard to get the header tubes glowing at idle with a lean AFR. Thanks. After doing TPS reset it starts fine but when you give it some gas it hangs at 1500 and will not return to idle. Consider adding fuel in the AE vs TPS and/or AE vs MAP ROC tables in the area where the stumble is occuring.Since this is happening at such low TPS levels it is possible that your engine would prefer a lower (richer) target AFR number at idle. I will let you know what the results are. It does this with the engine off. If i adjust the throttle plate screw in to bring IAC in to proper range say around 7 the engine is running around 2000 rpm. That Then, the next time I cranked it, the idle went high and won't come down!" Or is there something else I should The following are status commands and diagnostics for sensor and various parameters in the Holley software. I put it in neutral and the idle RPM had increased to 2100-2200. Ok, so I'm stumped! hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I I figured out I was going the wrong direction when I was messing with the AFR programming. The very first thing I would do is get ground truth on your timing. Adding a wrap to the return spring on the shaft is one alternative to solving this. You mentioned going from 13.5 to 14.2 but you'd want to go in the other direction--maybe to 13.2. We are running a Sniper on my mates 355ci small block V8 & so far he is very impressed ! Remove the tape from the IAC breather hole and restart the engine. But I wanted to go ahead and answer this so that it would make sense to someone who might not go that route.I think the first thing I'd do is try another pressure gauge. 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. Seems like its too slow to grab idle when ac kicks on. Turning it off and back on would reset it, and then it would work as advertised for a while. It sounds like you need a bit more of a fuel squirt on acceleration, Brett. I am new to the EFI scene but want to learn. The Super Sniper will allow you to monifor fuel pressure if you add an electronic sender but this is not an option with the standard Sniper. Idle when warm was 850-ish and IAC 3-4 just as when I readjusted it the night before. 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. Running the vacuum advance and of course I time it disconnected. At 0% it shouldn't be sucking any air through that port, correct? Im in Australia, so stuck the sniper on a 355 Holden engine with CD box. But before you adjust the ECU to lean the idle out, first confirm that your fuel pressure is right. When I put it in gear, it drops so low that it will stall if I don't add throttle. The TPS will go red with a -15 and the AFR reads heating for a split second, then the idle kicks up to 2000RPM. mail today. I.e. If you set the RPM above idle to start ramp too high, then it may not ever get down to the RPM above idle to re-enable. As always, I recommend great restraint in changing any of the parameters until a significant amount of learning has taken place. I recently bought the car with the EFI system on it. When the lambda is 1.0, the displayed AFR is 14.7;1 REGARDLESS OF THE FUEL. Were the additional load a simple step function it would be challenge enough for the ECU to gracefully increase the engine speed without overshooting.
Holley sniper, bogging/ losing power "NOW FIXED" I keep doing that with the same result. That way you can get into that part of the table that needs tuning, and you can watch your learn numbers grow. check out the. I think you will find that it will learn its way through this. Cracked casing from a side cover screw being installed crossed threaded.
Solving Holley Sniper High Idle Issues - EFISystemPro.com I took some pics of the sensors page this morning after the car warmed up. The Sniper EFI Manal says not to but many EFI installers have informed me that the transmission only reads the 5V TPS signal from the Sniper EFI & does not draw any power so will not affect the Sniper EFI TPS output. Idle Tuning is a very important part of tuning any EFI system, especially our self-learning units like Sniper or Terminator X EFI. Ok, we have enough Sniper systems out there that I thought it would be a good idea to create a posting on challenges that might arise during installation. All in all, considering the system has been installed for less than 2 hours drive time we're BLOWN AWAY at how quickly it is "learning" this engine. Thank you for any advice. Confirm the placement of all wiring, ensure that the WBO2 sensor is positioned properly, etc. Sniper EFI offers superior throttle response and wide-open throttle power. The fix? In your case, however, I think you're close to getting it running. Reply Quote.
Idle IAC problems? - Holley Performance Products Forums Chris---I am contemplating replacing my Holley 750 on my new low vacuum 600 HP 496 with the Holley Sniper FI system. :-). I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. When I turn it off and try to restart it just cranks. Don't try to correct for the fuel. But I still get the iac at 0 and the rpm at 1200. This is more of a bit of a reality check. ps. Thank you for your input. When the idle speed screw is turned all the way out there should be just enough room between the bore and the blade to catch your fingernail. Resistance results in heat and heat results in more resistance. Check fuel pressure too (. I'm happy to walk you through what is required. The hold position is part of the response that keeps the car from dying when you come off the throttle. Now, 1% on the TPS isn't a problem, but when it goes to 2% (which is inevitable if you have RFI moving it to 1%) then the IAC is going to go to it's hold position (30% by default) and the engine is going to rev up. Then you can take a close look at the IAC and see if it is opening. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. Others might require 60 RPM. Hope this helps! I would continue checking the electrical connections along the fuel supply. By the time I was near home, the idle in Park was 1050, IAC 0. Capability Range: Advanced If I were there in person I would test the function of the IAC (see this article.) It only comes back to normal if I turn the engine off and on again. You're going to have to get this fixed or it's going to cause even more problems than the high idle. I keep doing that with the same result. IAC is good 0-5% most of the time. New install, when in setup wizard TPS says 90 percent and I checked the linkage and butterflies. You can find those settings here: Handheld: Tuning > Advanced > Advanced Idle > Rampdown, Software: Idle > IAC Settings > IAC Ramp Down. If you did not rotate the distributor to set the actual timing to 15 that might be the only issue. When I first told him to check for leaks he looked back there and said "all good". Having a TPS that won't go lower than 9% will affect the acceleration enrichment correction, and could create a stumble at the first moment of throttle opening.Yes, the IAC can and will fluctuate depending on changing conditions. We're never going to fill up your email box with nonsense. I'm new to the efi thing and any help would be seriously appreciated. It is reliant on the data acquired by the included wideband oxygen sensor. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. My Sniper is 99% great! Idle quality is great, RPM is good, sometimes IAC is jumping around from 35 to 60. To be honest, you sound like an ideal candidate for Sniper ECU ignition timing control. Thanks for all your help Chris! What an amazing site you have here. The idle will not return to the set value.The second issue is the same as the first but the motor will stall out. nothing stays steady. But, if the idle is so high that it is making you crazy then you might try dropping that number just a bit. If your fuel pressure regulator has failed (and they often fail by blocking return fuel and maxing your fuel pressure) then it could lead to rich idle, particularly until your engine gets up to temp. If i set the idle to 750, the only way i can get it there is to turn the idle screw all the way out but then its at 0 iac. Give that a go and see if you don't make some progress! This curve runs fom -40 degrees to 260 degrees, and gradually reduces the RPM along that range. Yes, you are correct. Any suggestions? Bottom line ismy first one must have been faulty. But once you come off the throttle there is a minimum RPM that the ECU wants to see before it releases the IAC from the park position and that is normally 1000 RPM over the target idle. If you can send a data log to the vendor from who you bought your Sniper EFI System they should be willing and able to take a look and recognize RFI and then give you some ideas on solving it. Is there any chance that your timing has changed since you installed your Sniper? I have a Holley Sniper EFI with HyperSpark ignition. To get it to idle the tps is at 2-3-4% even with linkage disconnected and a return spring installed. I managed to get the IAC down to around 0% - 8%is this good? It is how the engineers allow you to clear a flood condition when you detect it. Can the return line be an issue?I have had 2 faulty gpa-4 255 walbro pumps go bad. Eventually the IAC will drop back to zero, I'll readjust it to 850 RPM & 2-9%, and then watch it steadily climb again. Due to when the pump i'm using now makes a loud howling noise when it gets ran for awhile and it gets at a 1/4 tank of fuel or less. I have it set at 650 and it idles anywhere from 590 to 700. Cheers Darren. It will still change a bit with weather changes and when you get into infrequently-used sections of the map, but it's nothing to worry about.Regarding your idle speed immediately after start-up, that is determined by your Idle Parked Position. me know how it works for you. You can manually set it 57 after you run the Wizard if required. Chris, First, recognize that the amount below your target where you set the hard idle will be different on different engines. Note: The IAC breather hole is the roughly 1/4-inch triangular hole that sits above and between the secondaries. This minimizes installation time and packages really well on a diverse group of engine applications. EFI parts, including the throttle body, and the problem persists.Please give me a hand. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. Ran 2 Holley carbs and an Edelbrock. Though they both are indications of the amount of opening through the throttle body, the TPS is the throttle opening percentage and the IAC number tells us how far the IAC stepper motor is opening the bypass air circuit.If I understand you correctly you are saying that the TPS reads somewhat normally (traveling from 9% to 100% or so) but that when you cycle the key it once again starts at 9%. A few, however, get tangled up getting the idle control working just the way they want. The on board fuel pressure regulator in the Sniper throttle body has a small filter clipped over one end . I went on the good ole interweb and found your website which was VERY helpful! I also tried changing roc/map to 8 from 15 again no change at all.My ve table is smooth and tuned I even changed my AFR to 13.5 from 14.2 and no change at all. If the IAC number is increased during this high idle, review the points about high idle from tuning issues. It works instantly for him.If that fixes your problem then you have a starting place. Then, when you experience the high idle, note if the IAC number has increased. Sniper setting is Stock camshaft. Handheld shows plenty of fuel so I dought it's an issue there. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. When I cover it with my hands, it gets quieter. Start with the most gradual throttle input you need to launch well, then slightly increase until you feel some stumble. installing and cruising down the highway 70 mph I just wonder if all I have to do Also its extremely rich at idle. If the IAC is zero, and if putting your finger over the IAC port doesn't lower it, then it's not the IAC circuit. Usually it wont stay on 0% very long and soon changes to another number like 1 or 2%. I enalble the idle timing control and fired it back up Iac was at 32% but it would come back down after a bit to around 26%. I've changed all the Yes it is controlling the timing and I had issues at first and it controlled the idle just fine. If you haven't confirmed that they it is worth checking. Thanks for any info./insight you can provide, Mark. Last night I tried setting the IAC and had the same problems after it's warmed up. I will try the other stuff when I get off work. I know its not flooded because I can pour a little gas in the throttle body and play with the accelerator and it will start and run fine. Engine has never stalled with Sniper system, once placed in Drive it just goes!!! Will restart but only for a minute or so a couple of times then shuts down fuel delivery and will not restart. Please let us know how this works out for you! That, I am afraid, is going to involve a little bit of luck if you don't want to create a 250 MB data log. I've been having problems with my sniper efi just shutting off. 3 different fuel pumps. Just wondered if you've ever run across a system not powering up? At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. The engine has 14: 1 compression ratio, we can not use gasoline. I tried adjusting my IAC up to 10deg in both directions with no change. Hi Chris thanks in advance for any tips. Chris I am having a little different idle problem I did your -40 thing and that help with high idle but my problem is it idles fine until I drop it in gear and it stumbles a couple times catches up and then idles fine again. Ive tried setting the prime setting above 150 but it wont take, it always goes back to 150. Wish I had bought my sniper from you, but unfortunately didnt. Good Have a look--I think this is going to allow you to fix your idle problem. Follow this link to download it for free if you have not already done so. You might have a bad IAC, but you can also have a bad vacuum pod on the transmission. I got it home, checked it all over, everything is hooked up correctly. 30 minutes later CTS reads 161, start engine Idle is jumping from 450 (almost stall) to 1500, IAC is jumping all over 10 90. I had this same exact issue. Also ensure the TPS Position returns to zero at idle, & the IAC Hold Position isn't setup too high. Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. At this time, TPS is 0%, IAC is 50 to 60%. Maybe Holley will add Fuel Prime Multiplier to Terminator X later. Intake has been on and off 3 times no change. https://www.gmperformancemotor.com/parts/19210007.html, http://forums.holley.com/showthread.3128#post83128, If this is your first visit, be sure to
Holley Sniper Iac Delete And your understanding of how the throttle position affects idle is exactly correct. I straightened that out, got it running and that's where it goes downhill. If you do find you have RFI issues then I've written an
article on solving RFI problems. It wont fire up. Try it! I've increased the IAC rampdown time to 8 seconds to try to combat this, but wondering if it will correct itself over time or if I need to possibly replace this TP sensor.
Holley Sniper IAC Problem - Holley Performance Products Forums 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. The engine makes very low vacuum at idle. Thank you. Then it changes and will not idle down, the handheld will display 0% IAC but you can see and feel that the IAC valve is more like 100%. Switch power to the Sniper on and crank the engine. However, I can't think of a single one that was because of low vacuum. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. With everything else being right and since you can make it start by adding fuel it seems like you must have some sort of fuel pressure issue. Engine warms up to 195 degrees and stays. So I had my Idle set up perfect, with idle timing control off and engine hot the IAC was right at 2-4%. I have not heard of this. I can adjust at 160deg, but my fans turn on at 180deg. So, this is what it takes to put a Sniper on a small-block Ford. Hello Chris. I'll bet you find that you can get it working great without any manual tuning. It could be that you've left a vacuum port unplugged, it could be that the throttle plates are misaligned (unlikely), it could be that your IAC is not closing properly. When I put it in gear, it drops so low that it will stall if I don't add throttle.