Do I need to try taping up the IAC port and setting the idle off the idle screw? If the screen shows iac at 0 and you block the hole to find it open what does that mean? 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. when things aren't working and this provides just that. Holley Sniper IAC Problem 04-26-2018, 11:30 AM Hello. Ive had an idle at neutral as high as 2400 rpm. It won't take much! Sniper EFI Tuning & Tech. So you installed your Holley Sniper. This is a mighty big subject for a blog post reply, I should probably start doing some videos on this. Maybe give it a half-turn before you start it and then start and tweak. Well you were right air was entering from another source. Follow this link to download it for free if you have not already done so. Comp. I am at the point where I almost insist that every Sniper EFI System owner purchase one of these. After a complete cool down it will do the same thing. I'm new to EFI and have no idea what to try next. IAC looks good once it finally s fires. I will turn it up some. Copyright 2017 Cyberspace Automotive Performance, Inc. All Rights Reserved. Turning off and then on again, the engine returns to normal. RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the Several good bits here. )Since this isn't a consistent issue with all Snipers that tells me that different IAC settings tend to make the whistle. Again, I would lean on that solution to let the vehicle drive/learn before you try to "fix" anything. ps. Try it! First thing I would check It runs perfectly fine other wise. The manifold pressure increases with the throttle opening but the RPMs are still low. 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. Physially manipulating the linkage by hand will generally reveal if you have a sticking linkage that is preventing the TPS from returning from zero. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. Two months fighting, cursing, not getting any help from Holley OR the forum, and a stupid little tin plate. If you patiently adjust this over the course of days you will get it just right.Again, glad this is working for you and look forward to a good report in the future! The Sniper ECU can use the timing to help maintain the idle speed and that will definitely be useful in that transition from Park/Neutral to Drive.If you don't have ECU-controlled timing, or if you do and it's not fully compensating, it may be necessary to increase your target idle slightly. Turned it off and on again. And the rather cavalier "Absolutely!" 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. Drop the IAC parked position a bit at each temperature point and sort of back into the solution. If you can track specific engine coolant temperatures where the engine stumbles and dies that would be a good place to start. Tuning Your Sniper EFI System for Progressive Secondary Link Use Note that sometimes you can get into a back-and-forth situation. I have one customer who is having some similar issues and his AFR is down at 9.6:1 when it won't start. 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. But he kept having problems so eventually he did a complete check and then he found the problem. Once it commands that high idle I haven't found anything to return it to normal, other than shutting it down and restarting. Was perfect idle iac reading 3. Price Point: $$$. Holley Sniper Iac Delete Just thought I'd ask as there isn't a lot of info out there. If it is not a problem with the Sniper EFI System itself then it could be an issue with some sort of harmonic involving the fuel pump. I am Japanese who attached Sniper EFI. 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. The IAC should display a 2-8% to bring the idle up to the actual target. At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. 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. Idles ok, runs great cruising, but from a stand still or downshifting and making a turn, when I get back into it, it wants to fall on its face. One of the signs of a vehicle with a rough idle is a faulty Idle Air Control (IAC) Motor. So, clearly, the "No" answer is wrong. Camshaft is M-6250-B303 .480 lift intake & exhaust, duration at .050 is 224 degrees for intake & exhaust. However I do have a couple of issues I hope you can help me resolve. Get a solid feeling for where it is when the engine is warm and the idle speed is correct. 1. Running new vintage air system so the is only a single power wire to compressor thats why I asked if I needed to run input wire to ac relay or if iac would pick it up fast enough(which its not). The fix? In the Wizard, select the stock cam setting. I'm compltely stumped and my wife is certainly upset I'm spending so much time between the garage and the computer for something that should basically run out of the box. My dad wanted to recheck the timing so I set the Static Timing at 15 and it runs perfect. Be sure to re-enable it once you get your idle tuned. Hopefully replacing the pump again will resolve both issues. 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. Thanks. We have never had that problem with any of the units that we have shipped. I did notice that when I thought I had it set THANK YOU for the "First--Check Your Idle Speed Curve Setting!" I'll bet you find that you can get it working great without any manual tuning. That is what I really respect about Holley. Good luck! We're never going to fill up your email box with nonsense. 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. TPS 0. Sniper EFI Idle Tuning. Then, when you experience the high idle, note if the IAC number has increased. When I see that your TPS is 1%, that tells me that you may have an RFI problem. Holley will take a look and tell you you have RFI and wish you good luck in finding it. Fuel Flow lb / h = 12.1 About two minutes after I get it set at 850 & 5%, it has progressed to 100%. Will restart but only for a minute or so a couple of times then shuts down fuel delivery and will not restart. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. What might cause the TPS to go to 2%? 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. Based on your situation above as well as some of other experiences, I recognized that I needed to improve my tuning procedures above to better explain what steps to take if that 10-step process doesn't completely solve the problem. Ive also used another snap on light to confirm. What you are experiencing is rather common. :-DStill, I hate to leave someone hanging so I'll try to help. Holley Sniper EFI 550-552 Holley Sniper EFI Autolite 1100 - Gold Somehow air is entering the engine that was not entering the engine when you originally set the idle speed screw. Then do it just a bit faster--just enough for it to bog a bit. New install, when in setup wizard TPS says 90 percent and I checked the linkage and butterflies. I'd say make sure you buy from someone who can give you good after-purchase help (hint!) 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? After 50 on the throttle position I'm not sure if the whistle goes away or you just can't here it anymore. Chris, I recently installed my Sniper and have an intermittent idle problem. That will happen occasionally, but less as time goes and on and the engine tune stabilizes. I have been able to get it pretty The Fuel Base map is perfect, the car works well, runs well, running through the streets, the car is great. However, I always preach to never touch any of the controls on the handheld until you have a couple hundred miles on the engine in a range of driving situations. Holley Motor Life The person I bought it from said he never could get it to run for more than a few seconds. mean that the IAC is causing it. Ok, so I'm stumped! As always, I recommend great restraint in changing any of the parameters until a significant amount of learning has taken place. I've made all the adjustments, all the settings, and the IAC issue is driving me crazy. Also ensure the TPS Position returns to zero at idle, & the IAC Hold Position isn't setup too high. How To Adjust Iac On Holley Sniper It turns out that some of the Snipers are shipping with the minus 40-degree setting drastically lower, as shown in the following image. idle at 1100 on the "stock" file it's better with street strip.The IAC counts will be at zero. For the first couple of drives it was running well, Sniper EFI was working exactly as advertised. Possibly cap, rotor, coil? That could be a problem with the TPS or it could be some sort of throttle linkage issue. :-). nothing stays steady. After speaking with Holley Tech Support and Tech Support from where I purchased the systemthey decided to replace it. You should get a light spray evenly distributed in all four barrels. Does that make sense to you? I've been trying to correct that 1% small issue/annoyance. The fuel pressure regulator in the Sniper is fairly simple and not prone to failure, as far as I know. My Sniper is 99% great! Sniper EFI offers superior throttle response and wide-open throttle power. Hope this helps! Remove the tape from the IAC breather hole and restart the engine. How can I adjust the startup speed down to about 1400 RPM? Please advise. Inj. With the vehicle in neutral, adjust the idle screw until the IAC Position reads between 2 and 10%. that my Air/Fuel ration was 15:1 and I believe the target is 13.5:1. Clearly, something is changing. Save Share. Could you provide me with some things to check or some things to adjust? Thanks again Chris, your help has been invaluable.If anyone is considering going EFI, Chris is the man to chat with. I emphasize "and" because the transmission controller manufacturer I used had the TPS ground terminated within the harness to the unit's main ground, which I find to be an unthinkable choice. Lubricate the linkage so there isn't as much native resistance. We do that but most places don't. Once you've done this, the next natural step is to transfer the learn table to the base map, then go in and smooth out the sharp edges, which are going to be at these transitional states. 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. My IAC was constantly at 100% at idle. These aren't generic newsletters either but instead personalized emails. :-). it will jerk and rpm will go up and down and AFR will be around 20 : 1 or more or less. The RPM would increase for no reason. This may sound crazy but I'm going to jump out on a limb here and say you don't have an idle issue--you have a timing issue. Price Point: $$, Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. back to trying to zero down an idle. Setup: 1965 Impala SS; ZZ6 Crate Engine, EFI Distributor. At low levels RF interference will often reset the ECU so quickly that the engine will not stall. We will definitely be sticking with Holley from here on out for future retro-fits. Have a look--I think this is going to allow you to fix your idle problem. 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. But I am having troubles.When stepping on the accelerator slightly with idling, it will be 2000 RPM all the time. Do please let us know what you find out! Engine warms up to 195 degrees and stays. Thanks again. I think that this time around you will find that it starts and idles really well and only gets better from there. Now it registers zero and I have good idle but it will not register until it hits 60 and up. I will confirm TDC with balancer but I have had balancer off and timed it before and after with same results. The biggest issue is these problems are intermittent meaning they do not occur all the time. Generally, one of two things: a stuck throttle or noise on the TPS signal. If not then I think you are going to find that this will solve much of your problem. I was shocked to see it at 95lbs!! There is a chance that the IAC is open but displaying 0% so start by putting your finger over the IAC opening. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. The fuel pump is mounted under rocker panel as low as possible and far away from any heat. The TPS will go red with a -15 and the AFR reads heating for a split second, then the idle kicks up to 2000RPM. Solving RF Interference Issues in Sniper Installations - EFISystemPro.com And, hopefully, within those degrees you will find a place where you don't get the whistle. As you have noted, each time the idle goes up. At this time, TPS is 0%, IAC is 50 to 60%. If they are closed, check the primaries. It could be that the air flow across the secondaries as they are opening is creating that whistle but that isn't commonly the case.Did you check for leaks around the gasket of the air cleaner? NOTE: Do not attempt to set the target idle speed and IAC position until the engine is above 160F! This curve runs fom -40 degrees to 260 degrees, and gradually reduces the RPM along that range. I appreciate the help youve given to everyone as it continually helps me! Also if I give it a Sniper EFI - Holley This will let you know at a glance if something is going awry with the fuel pump. I've abbreviated it just a little bit but am appreciative of the added insight your comments provided.Off-idle performance can really be a challenge to self-learn but be assured that it can almost always be done. Could the IAC be broken/malfunctioning? However, I can't think of a single one that was because of low vacuum. 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. 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. It started right up and we did your idle control fix and all is good at idle. Idle : IAC Rampdown : IAC hold positionChange this by maybe 2% in either direction. Running a bbc with coil - my timing is perfect. I've not heard of any others with this exact issue so I don't think it is a common problem. :-). carburetor setup, but it does blow when I can't jump on the highway like I use After pumping the pedal a few times at different times it dropped to zero and started to work. But if you will just advance the timing at idle and see if it makes a difference then that will tell you what you need to know. My car will not idle right until it gets to around 130 -140 degrees. Once engine is warmed up been driving for awhile. I pulled over and turned the car off and then back on. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds Duration @.050 is 240 intake 246 exhaust with .574/.578 lift. Ive tried setting the prime setting above 150 but it wont take, it always goes back to 150. 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. I have a 406SBC that does most everything right with this sniper setup. Enjoy! So glad this was helpful. But there are several degrees of play there in which it should still work fine. Be aware that there is a spring behind there and a diaphragm that you don't want to tear. I'm wonder if the iac can cause this. If you go the other way then you might find that the IAC zero's out when the fans are off. Throttle Tip-In puts you in a part of the fuel map where you stay for only milliseconds at a time. He has walked me through every question Iv. Im thinking a faulty TPS. When this happens, it is impossible to convince the Sniper ECU to allow the RPM to drop below a set RPM--regardless of what the target idle speed setting is. Drive great and idles perfect at stop signs. If idle drops below 800 it wont come back itll chug around 300 rpm for a few seconds then die. The window you saw in the image above pops up. I installed a sniper efi system on my 1969 Camaro. I am new to the EFI scene but want to learn. have the system learn the higher speeds? It may take a few tries. = 2.34 Cl. shut truck off. It didnt do this with the carb on it. Im in Australia, so stuck the sniper on a 355 Holden engine with CD box. Get On The List for Emails Straight From Our Pro? What I can't explain is why your TPS is acting so randomly. I would continue checking the electrical connections along the fuel supply. The motor has 376hp at flywheel and the car is a stick shift. SNIPER EFI TO HOLLEY DUAL SYNC HARNESS Part# 558-493 $34.44 Qty: Add To Cart Idle Air Control Motor 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 Part# 543-105 $71.72 Qty: Add To Cart 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. Both answers you've received greatly oversimplify the truth in favor of the answerer. If you do find you have RFI issues then I've written an article on solving RFI problems. When you set the Static Timing to 15, what did you read with the timing light? But I can tell you that for most people who try this it introduces so much RFI onto the Sniper that it never works right. Nice to meet you. But when you have it then you can look for exactly what the IAC is doing at that point, and if there is anything that might lead to this happening. I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. This car has never idled under 900 without stalling with 3 carbs and does the same thing with sniper edit. I have driven it a few times maybe 100 miles or so. Don't make any changes more than about 10% and keep the same basic shape as the original (High/flat below 20 degrees, sloped downward up to 180 degress, and then flat again above that.) But now that Terminator X is available, I highly recommend going that route. In most cases the IAC (Idle Air Control) circuit is the source of the whistle. They tell you to ask call Holley. Advanced throttle body injection systems capable of transmission control and more. 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. Throttle body mounted ECU - no extra boxes to mount. :-). Hey Tommy, we've got at least one thing in common. Your task will be to find that. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. The hold position is part of the response that keeps the car from dying when you come off the throttle. And, while that is happening, make a note of the temperature before you engage the starter, and then the rpm when it starts.The Idle Parked Position is set on a temperature-based graph like the Idle Speed Curve. Another suggestion is to add an extra turn to the spring built into the linkage to increase the closing force on the throttle shaft. It only lowers to 2-6% when I take my foot off the gas. There's nothing wrong with manual tuning, but at this point that is just compensating for an inadequate fuel map. holley efi. Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. Intake has been on and off 3 times no change. Idle was back to normal but iac was at 0. Thanks! Any help would b great. They are prone to be inaccurate. Check the Distributor Tach Connection to the EFI. The Sniper EFI system looks at the closed-loop fuel compensation required to reach your target AFR. You mentioned going from 13.5 to 14.2 but you'd want to go in the other direction--maybe to 13.2. Well, it sounds to me like your Sniper is doing its best to reduce your idle. 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. No air should be able to pass. There are a few tell-tale signs that can help you diagnose the problem. Sniper EFI Initial Startup and Troubleshooting Staff Writer 01/20/2020 An under-sized filter will allow part- throttle operation but fuel pressure will drop at WOT and run very lean - perhaps surge under power. Hot start it most of the time wont start unless I give it a little throttle. Except at idle. 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. Tuning > Advanced > Adv Idle > IAC Startup You can drop it down and you will find it will behave more like you expect. That is the first thing you must find. Unless you have ignition control enabled, that is the only thing it can do to reduce the idle.Realize the only things that can cause the car to idle up as you describe are air and ignition advance. itself out and hold idleeventually stalling. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! Or is there something else I should By the time I was near home, the idle in Park was 1050, IAC 0. School's out for spring break this week though so I'm covering for employees on vacation. This is normally used as an A/C idle-up circuit. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? If that happens then follow my 10-step process shown above. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. Tried that and it didn't work? Thanks Again for your help. https://www.gmperformancemotor.com/parts/19210007.html, http://forums.holley.com/showthread.3128#post83128, If this is your first visit, be sure to I called support line he said he would have to look into it and call back. )Take a look at your AFR during the starting process. 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. One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. However based on your reply I connected the Fuel Pressure gauge and Sorry for all the questions, new to the efi world. Yes, it will talk to you--but not with words. 680-700.I can't find any reason other than it looses where it is in the firmware with The throttle position should be zero. Also what would you say a desired idle should be for a 3 speed automatic ford? I' m going to put the 3rd new pump this coming friday. 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. Any suggestions? And your understanding of how the throttle position affects idle is exactly correct. If it is already adding fuel, it may be worth expanding this into the area where the tip-in is occuring (and where there is no learning occuring. 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. I did buy the Sniper from you guys and the service was fantastic. Going back to what you said. 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. See these. Well, it turns out that with the current firmware this throws the IAC control into a bit of confusion. The first place my eyes go when there is any issue with the idle is to the TPS value. The throttle plates are misaligned. WIthout knowing quite a bit more it will be more than challenging for you to identify the problem and solve it.Fortunately, Holley provides their amazing Sniper Software. My sniper is doing two thingsFirst issue, the idle is set at 800 and will idle fine, then There is a glitch in the system. Going lower with the blanking might pay dividends, but there is so little room below 7/8 that you will quickly be in a range where every tiny variation in the TPS or MAP is throwing extra fuel into the engine. My primary reason for going EFI was drive-ability, (Startup and take off without waiting for the engine to warm up) and not have the occasional hesitation a carburetor has especially just barely opening the secondaries. IAC Testing Procedure for EFI Systems The link above includes the option to buy a -6 AN They also recommended that their ground be spliced into the Sniper ground as close to the Sniper as possible. I am right back to where I started. Should it not do the opposite and do this on a cold start not warm. 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 feeling it's something simple but I thought I'd ask you first before I inadvertently change something that affects other areas. This page was generated at 12:25 AM. Sniper is still learning so it will continue to improve.Second, you may have heard the phrase, "correlation is not causation." Do you have any clue? 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. Thanks for your very detailed question! I think that the more important point is that Holley kept sending him units until everything was working. Plus, you can email that file to me and I can be of more help. Installed sniper on 65 galaxie. As inconvenient as it might seem, I'd recommend keeping a timing light handy and checking your timing during the high idle condition and then again after restarting. By the way, this is a new installation on a 69 Camaro, stock 350, dual sync, etc. I can tell you that when things aren't working the way you wanted them to work that nothing beats knowing for-sure that you don't have a fuel supply problem. I asked him a million questions and waited a long time to save up before purchasing the system and I have asked a lot of questions throughout the installation process. Always had to set idle above 950. Perfectif you have the original synchronous linkage. A couple of possibilities that come to mind in order of likelihood: Im having an issue with what I think is the Iac. I did check for the lightning under the hood but all was well. i would have been happy to answer there.