So you installed your Holley Sniper. Does this seem reasonable and how hard will it be to get the idle and off-idle performance correct? Member List; Calendar; Forum; Holley EFI; Sniper EFI; If this is your first visit, be sure to check out the FAQ by clicking the link above. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? engine works beautiful, the car runs a lot, but suddenly, the engine does that. It only comes back to normal if I turn the engine off and on again. 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. idles good, runs amazing. It could be a problem with the power/ground for the Sniper but much more commonly this is a result of too much RFI. If I go any more it will ping. I have installed my Sniper and the car runs great. I was shocked to see it at 95lbs!! 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. Has a good size camshaft cant find any vacuum leaks. I cut and heat-shrink wrapped the 5V wire and then ran both the signal and ground wires all the way back to the transmission controller. NOTE: Do not attempt to set the target idle speed and IAC position until the engine is above 160F! Seems like its too slow to grab idle when ac kicks on. I did change the -40 thing also. The manifold pressure increases with the throttle opening but the RPMs are still low. Do you have a PCV on the engine? If I put the truck in park it comes down to idle. 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. That is the default "Clear Flood" TPS setting and turns all fuel off until the engine cranks. :-). That way you can get into that part of the table that needs tuning, and you can watch your learn numbers grow. Plus, you can email that file to me and I can be of more help. Adding a wrap to the return spring on the shaft is one alternative to solving this. The headache is the Acceleration Enrichment. This will go a long way to improving your fuel map without manually adjusting the acceleration enrichment. I didn't find your site until I was having trouble. The Sniper EFI remote IAC (Idle Air Control) and plug is designed to gain installation clearance on some Sniper EFI 2x4 installations. Hello Chris. first attempt but as it tries to idle down to the target RPMsit can never even Did your process to adjust idle to 860. Holley Sniper EFI Troubleshooting Mudford Garage 8.6K subscribers 38K views 3 years ago My Bronco with Holley Sniper EFI was running poorly. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. I'm happy to walk you through what is required. Turn the idle speed screw on the primaries in about 2-3 turns after it makes contact with the linkage and starts opening the primary throttle blades. What should I be looking at to calm this down? The broad consensus has been that the Sniper is an amazingly straight-forward install and starts and tunes as expected. 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. If so remove it. Coming home from work today it was much warmer and took a little longer due to traffic. Two things to keep in mind as you do that. Have you ever experienced a high idle once the engine reaches 200 degrees?Ive set my idle the way you said and it works great until the engine reaches 200 degrees. The learn percentage should gradually decrease to virtually nothing as the map plus learn table begin to get more and more accurate to your specific setup. Yes, it will talk to you--but not with words. Intake has been on and off 3 times no change. Throttle Tip-In tuning can be a bit of a challenge but I'm confident you can get this resolved, Mike.Let me start by saying that unless you've really done a lot of driving on the system in some useful learning situations then I would set this issue aside and not even think about it. I installed a sniper efi system on my 1969 Camaro. Edit I just ordered a Holley return / regulator and cap for the sniper ouletOh, this is not an OEM Master Kit, but the fuel pump should be the same EFI Pro shipped this kit. They always responded to my questions with guidance that helped me choose the right system for me. To keep it running in gear, I have to bump the neutral idle up just over 1000 RPM. Last night I tried setting the IAC and had the same problems after it's warmed up. Realize that when you drop the throttle, the engine enters a condition it will only see for a fraction of a second at a time. View Holley Sniper EFI Self-Tuning Kit - Shiny Finish. So something is triggering the ECU to be in Open Loop. All of the wiring exits below the rear fuel injector cover, for a completely stealth installation. I would disregard any correlation between idle control between the Stock and Street/Strip setups. It starts cold fine, its just when its hot. Is there away to lean the idle out? THANK YOU for the "First--Check Your Idle Speed Curve Setting!" By the time I was near home, the idle in Park was 1050, IAC 0. 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. One of them might be faulty. Since that has long been corrected we have moved that information to the bottom of the article.). Your AFR is pegged lean. Do you have any clue? In your case, however, I think you're close to getting it running. Once it commands that high idle I haven't found anything to return it to normal, other than shutting it down and restarting. Price Point: $, Advanced throttle body injection systems capable of transmission control and more. The only way to confirm RFI problems is by doing a data log. Capability Range: Advanced Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. You're going to have to clean up the wiring in your engine compartment, In particular, look for spark plug wires that might be running near your throttle position sensor. Its just at low speeds, not sure if its loading up or leaning out. Laptop Access We're having trouble with a Ford Maverick 302 V8, using ethanol. have noticed on the hand held is that Air/fuel Ratio rises to 20 +/- A/F and the I'll have to check again tomorrow. Installed sniper on 65 galaxie. When I first told him to check for leaks he looked back there and said "all good". check, I guess after reading everyone saying how great the system is after It has gotten a little better after I drove it for three hours today.I want to save the Kik because if I get this working good then I would like to add A C and use the kick for it.Motor is Mopar 360 with mild cam and automatic. Then it started behaving oddly. We'll also be contacting you for future purchases now that I've discovered you! The last pic is with the car in Drive. There is no sense proceeding until your TPS is at zero at key-on. Hello Chris. It shuts off when coming to a stop sign, at any cruising speed and romdomly at idle in park but never when excelerating. Honestly, I've never seen this happen but if the butterflies were misaligned on the shafts it could allow too much air to enter. 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? Once we recognize that, the next step is to narrow down all possible sources of additional air until we discover the cause.Start by keeping an eye on your IAC number. Remember that as an EFI System Pro customer you have access to me at any time via my cell phone. In some cases, you may only be able to put as little as 10 RPM between the hard idle and the target idle. Good luck! Target AFR at idle is 13.8%. It wont fire up. Next, clean the IAC and all related parts with brake cleaner. Once it decides to come back down, it does so with no issue. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. First, I'm kind of insistent about not changing any of the default settings unless the vehicle absolutely will not cooperate enough to drive/learn, and only then if you have a specific understanding of the problem and a specific solution. The whole topic of using the Sniper TPS for transmission control is one deserving of it's own article but I'll try to summarize a bit here. If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. Running a bbc with coil - my timing is perfect. In the setup, I set the hot idle for 850. Changing the rpm curve and target rpm has no effect. The engine runs beautifully, with perfect idle at 650 RPM, but every now and then I hear the IAC give a sort of "snap" and the idle is at 1200 RPM. When I shut it off then start it Give us a hand! When you have the issue you should disconnect all hoses and plug the ports on the Sniper. I think you will find that it will learn its way through this. Get that thing installed and you're going to know a whole lot more about what's going on. I think that this time around you will find that it starts and idles really well and only gets better from there. Add To Cart. I have changed my roc/tps to 7 from 15 but that only took me out of learn mode. My issue is that when Im in stop and go traffic, I can let off the clutch and the engine revs and doesnt quite want to come back to idle. The next time it happens is the perfect opportunity to find the problem. Should i adjust idle screw with the fans already on? A few, however, get tangled up getting the idle control working just the way they want. 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 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. Does that make sense to you? Start by doing the fastest start you can that doesn't bog. I'm running a 408 sbc. Thanks for any info./insight you can provide, Mark. I set it exactly like the instructions said and my iac is not only all over the place but when I finally did get it to the 2-10 range it's highlighted in red. Even then, recognize that over time the IAC will need to be readjusted to compensate for minor changes that will cause it to drift. Sniper setting is Stock camshaft. No air should be able to pass. Why is this? Hello School's out for spring break this week though so I'm covering for employees on vacation. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! Idle > IAC Kick. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. 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. The Sniper even has a feature that allows it to use the idle timing to control the idle speed. No power at the programmer and no fuel pump running. Advanced throttle body injection systems capable of transmission control and more. 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. One of the best Ive seen so far. I installed my Sniper and the engine fired up great. Please help. If that happens then follow my 10-step process shown above. On startup- cold or hot, I get a 2 second high idle of about 1500 RPM before normal set idle of 750 RPM happens. Then you can take a close look at the IAC and see if it is opening. A good example of why it's so important to run a good pre filter in the fuel line. The idle is 1350-1400 with the idle screw at initial contact. If you go too low then it may stumble or even stall when coming off of throttle. A problem since day 1 - YouTube Leave a comment if you've had this issue and how you resolved. Its timed to 36 degrees. May God's grace bless you in the Lord Jesus Christ. But another thing to consider is adjusting your target A/F ratio. I think that your Sniper system is working fine but would definitely check ouf the fuel pump. If you remove the air cleaner entirely and the whistle continues then you can rule that out. It is temperature dependent but 30 is commonly where you find it. I've been messing around for a bit trying to eliminate any possible vacuum leaks. We can not hit it at all, we hit the pedal abruptly, the engine gives a lot of excess fuel, the AFR gets super poor at first, the car stops, then the AFR gets super rich and the car runs until it cleans up. But if I take off from a stop and go to 1/4 or 1/2 throttle its fine and takes off like a banshee. Both answers you've received greatly oversimplify the truth in favor of the answerer. The latest was changing the power brake booster.Today I drove it to work and no issues at all. Clearly, something is changing. About two minutes after I get it set at 850 & 5%, it has progressed to 100%. Doesn't want to start, runs like crap. Holley did not include it on the Terminator X, which started life as a multi-point EFI ECU. 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. I have checked the pink wire and it is at .001 volts when key is off. 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. The motor has 376hp at flywheel and the car is a stick shift. May God's grace bless you in the Lord Jesus Christ. 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. Enjoy! There are two ways to address this--you can let the system learn or you can manually adjust the acceleration enrichment. Chris, I will a, Scott has been very helpful and informative on guiding me through the purchasing and installation of my terminator X max system. I hold my foot steady in place it does this in 5 second cycles and if i let go of Give it a watch: https://youtu.be/7SO7-tZn6iw. When I am coming to a stop, the rpms will hang at 1200-1500 rpms. You can manually set it 57 after you run the Wizard if required. Its on a big block Mopar with stock electronic ignition . I can drive it a bit but pops through the throttle body when pulling out from a stop (4 speed) and sometimes in the exhaust out on the road. 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. I ask because I'm using a PCV valve with my Sniper and have random idle issues as well. If idle drops below 800 it wont come back itll chug around 300 rpm for a few seconds then die. Hi Chris , greetings from Down Under (AUS) Just a note on the hi fuel pressure issue . That initial rev is going to be determined by your IAC Park Position. Great work, expert! Observing the temperature on the 3.5-inch handheld (only), wait for the temperature to achieve 160 degrees F. Once above 160 degrees, turn the idle speed screw so that the idle is about 50 RPM below your target idle speed set in step 1, above. I put sniper on in hopes to be able to just turn key and start without fumbling with pedal to keep it going and to correct idle drop when ac kicks on. Your task will be to find that. No problems with either cold or hot starts. Maybe Holley will add Fuel Prime Multiplier to Terminator X later. 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. If it does then you can put on a heavier spring so the advance doesn't come in as fast, or use a lighter weight. You'll have to go back and forth a couple of times to get it just right. Holley EFI Electronic Fuel Pressure Gauge, article on choosing between Sniper and Terminator X throttle body solutions. First, recognize that the amount below your target where you set the hard idle will be different on different engines. So this is my issue ( I did just email Holly). It meets the target idle perfectly in either but if I lightly stab the throttle it tries to stall after slightly revving. This curve turns the idle speed down as the engine warms. Please advise. Once you have done this the challenge is to create a datalog that includes the ":snap" you describe. I believe that you have this problem solved now with your new inline filter/regulator. That will happen occasionally, but less as time goes and on and the engine tune stabilizes. Is there away to program the ecu to compensate for this at start up. Perfectif you have the original synchronous linkage. This was an issue in the earliest version of the Sniper firmware. 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 installed a Holley Sniper on my Ford Maverick 302 V8. If I adjust idle screw out to get the tps to zero or even 1% the engine will not idle. I figured out I was going the wrong direction when I was messing with the AFR programming. So what--you're never going to drive in minus 40 degrees, right? I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. Turned it off and on again. The only way to do this is by installing a mechanical fuel pressure gauge. A question I cannot get a 100% answer on is can you piggy back off the Sniper EFI TPS for an electronic transmission? idle counts from 0. But if you can datalog the bog you can know much more precisely what is happening. In that case, and if you have an EGR valve, I might be suspicious of something going on there. Take it a step at a time. The ticking is inline with the fuel pressure I feel squeezing both the fuel return & delivery lines (like a heartbeat). 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. Holley Sniper IAC Problem 04-26-2018, 11:30 AM Hello. In the time it takes to add your email address you can be at the top of the heap for getting the latest information from our authority. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. If the regulator is working correctly and there is no restriction in the return line that should make no difference however.Sorry I didn't see this on the Holley forum. Your closed loop compensation is adding a full 50% fuel. But, if the idle is so high that it is making you crazy then you might try dropping that number just a bit. I used the Casper's Electronics 108103 splitter and carefully soldered my connections. When I covered the IAC with my finger, the RPM dropped so low it stalled. I watched the butterflies start to open at about 35 on TPS. 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. When you first posted this I had no idea how to respond. 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. That is likely just confusing the issue.Instead, choose whichever setup most resembles your camshaft and stick with that. 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. It's all part of the pleasure of EFI. If I try and get the 2-10% i get all the way up to 1200 rpm. Any suggestions would be appreciated. You can find those settings here: Handheld: Tuning > Advanced > Advanced Idle > Rampdown, Software: Idle > IAC Settings > IAC Ramp Down. By the way your site and your accessory products are nice. So as much as I can I have been taking off real slow and let it fall on itself to try to learn and its not learning its way out of it. When the secondary throttle blades are centered in their bores and pivot freely, an additional return spring is not necessary. = 2.34 I have an entirely separate article on Solving RF Intereference Issues. The Sniper Quick-Start Manual provides the following instructions for setting the idle. EFI Systems based on Holley's world-class Dominator and HP ECU's. The engine has 14: 1 compression ratio, we can not use gasoline. I have probably 200 - 300 miles on this engine and it has always done this. Hello Chris. You could go either way.. As soon as I got the new one installed and wiredit fired right up and did everything it was suppose to do with no issues. It runs perfectly fine other wise. Ensure all your sensors are displaying proper values. that my Air/Fuel ration was 15:1 and I believe the target is 13.5:1. Thanks, That is an strange situation. I presume your idle speed table doesn't increase at 200 degrees? But after sitting static idling for a little bit, the IAC goes to 100% & stays there. the issue (If you do this you will need to reset the -40 degree setting mentioned at the top of this article. Holley Sniper IAC Surging???? When I drive with warm engine the IAC is at 30% when pushing gas, but shouldn't it be at 0%? Engine has never stalled with Sniper system, once placed in Drive it just goes!!! Thank you. That is certainly not normal! I recently bought the car with the EFI system on it. 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. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. when things aren't working and this provides just that. 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. If it is then something is commanding the ECU to open the IAC. The problem I'm having is I cant get the IAC to drop down off 100%. Should the iac% fluctuate? Others might require 60 RPM. I'd really appreciate some help. Cl. I have driven a stand-alone transmission controller for the 4L60E in my (then) Sniper-equipped '95 GMC pickup using the Sniper TPS with complete success. Bryan McTaggart 02/28/2023 news Find a lower price anywhere and we'll beat it by 5%! It's not that they (or any other manufacturer) is 100% perfect. You may have to register before you can post: click the register link above to proceed. My Sniper is 99% great! If more info is needed just ask. Properly configured, the Sniper does a fantastic job of responding to the transition from Park to Drive. Those little 1/8 NPT gauges are pretty inexpensive and generally pretty easy to find locally.If you confirm that the pressure is indeed 90 PSI you could pull the fuel pressure regulator apart and check it. Any ideas here? I have a Holley Sniper EFI with HyperSpark ignition. The IAC going to 30 is normal. Sorry I didn't buy from you but I didn't know you had sold them. It will learn the fueling eventually either way, it's just that one might get you there a little faster.If the idle is fine at start-up but then increases after you depress the throttle then you might need to lower your IAC Hold Position a bit. 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. 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%. When I see that your TPS is 1%, that tells me that you may have an RFI problem. would correct it (as it has for a multitude of other drive-ability issues) but this one little glitch seems out of it's range. If you are using your Sniper EFI System to control timing, navigate to Tuning > Advanced > Advanced Idle > Idle Spark and ensure that the Idle Spark Enabled is set to Disabled. The very first thing I would do is get ground truth on your timing. Inj. If you've been running a filter then you have to wonder if you have a legitimate Walbro pump.If you install a new pump and the noise is still coming from the Sniper EFI System then only the dealer who sold you your system can help you. Shut it off and immediately restarted and idle was now 880 with IAC at 8.If this is a vacuum leak I can't figure out what would cause it to go away immediately after shutting down the car and restarting. I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. So check that timing and I think that you're going to find you need a good bit of advance. Hopefully replacing the pump again will resolve both issues. Ive also used another snap on light to confirm. Of the two options, I generally recommend the self-learn. I haven't driven it for the 30-40 minutes like the several times it idled at 2200. It's all part of the adventure! This page was generated at 12:25 AM. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. Not good.There isn't set solution here that works for all engines. Yes it is controlling the timing and I had issues at first and it controlled the idle just fine. :-). Idle was back to normal but iac was at 0. But I think it is safe to say that you are now at a point were some manual tuning is a good idea. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. It then started working normally again. The person I bought it from said he never could get it to run for more than a few seconds. First thing I would check In the warm state IAC adjusted to a position of 2 to 10%. Free ground shipping regardless of order size! By going into the IAC settings and turning off the Idle Spark control and setting Target Idle to 750 RPM my idle issues are gone, and it now returns to desired idle after cruise. But they are 100% committed to your satisfaction. )Then look a the datalog and find out what TPS ROC and MAP ROC is most likely to cause the problem. Physially manipulating the linkage by hand will generally reveal if you have a sticking linkage that is preventing the TPS from returning from zero. It is probably that your RPM above the maximum point at which ramp-down can occur. 400 engine, C6 3 speed automatic, with standard canister coil for ignition, and If you go the other way then you might find that the IAC zero's out when the fans are off. This page was generated at 12:25 AM. Ok, so there are a couple peculiar things going on here. It drops about 200rpm when clutch engages. Give that a go and see if you don't make some progress! (Don't drive and watch--get a helper!) The throttle blade adjustment is at 2-6% at hot idle, and with warm engine 185F.