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. Going back to what you said. Wish I had bought my sniper from you, but unfortunately didnt. If you do find you have RFI issues then I've written an . From herethe cycle continues and I am I have verified that there are no vacuum leaks, not to mention the car runs to good to have a vacuum leak bad enough to make this noise. This software is going to allow you to open both the configuration file and the datalogs that you create, overlay them and you can get a much better idea of what is happening. 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. Have a look--I think this is going to allow you to fix your idle problem. Please check your process again and see if you can see very specifically what is not working correctly. Good IAC looks good once it finally s fires. Get On The List for Emails Straight From Our Pro? the gas it catches itself and runs fine at slower speeds. Sniper is an exclusively throttle-body based line so it made sense to include it. This minimizes installation time and packages really well on a diverse group of engine applications. When I see that your TPS is 1%, that tells me that you may have an RFI problem. I'm also having a high idle problem but its different. Fortunately, I have an article that goes into this in some detail. Thanks for the information you have provided on this site. Start engine let it warm up to 160, learn mode is learning. Did your process to adjust idle to 860. At this time, TPS is 0%, IAC is 50 to 60%. I'd really appreciate some help. Of the two options, I generally recommend the self-learn. Sniper setting is Stock camshaft. check out the. The progressive link can be a great solution on standard (non-Stealth) throttle bodies but I would install this LAST after everything else is working perfectly. Then it will ramp down to 1200 but will not return to idle. If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. :-). )Take a look at your AFR during the starting process. This will go a long way to improving your fuel map without manually adjusting the acceleration enrichment. *Possible delays due to Covid-19 click for more information. Remember that as an EFI System Pro customer you have access to me at any time via my cell phone. Duty Cycle% = 3 I recommend confirming there is no throttle linkage issue first. Will restart but only for a minute or so a couple of times then shuts down fuel delivery and will not restart. I hold my foot steady in place it does this in 5 second cycles and if i let go of What is it supppse to be at idle and while driving under heavy acceleration? It then started working normally again. Or, at least, it should. A couple of possibilities that come to mind in order of likelihood: Im having an issue with what I think is the Iac. Yes, it will talk to you--but not with words. Both answers you've received greatly oversimplify the truth in favor of the answerer. I have quadruple checked my wiring and am certain it's correct. Even though you think your timing is perfect I'd suggest you try cranking about 5-10 degrees of advance into the distributor and just see if that doesn't work better for you.Remember this: adjustable timing pointers go out of adjustment and harmonic balancers slip. Get a solid feeling for where it is when the engine is warm and the idle speed is correct. started up the engine. I have it set at 650 and it idles anywhere from 590 to 700. This is extremely unreliable afrer warm. An undersized or partially plugged fuel filter is a classic EFI installation mistake. 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. Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. I'm thinking it could be the fuel pressure--- since I have a new Spectra EFI tank and there's been some reports of the interior coating coming off and gumming up the pump however the sniper display DOES NOT show fuel pressure.the Sniper DOES measure fuel pressure on its own - i've confirmed that with holley techs as they told me to purchase the fuel pressure gauge that can just hook up to the 1 wire gauge harness from the Sniper. I did all of this before seeing the link you sent. :-). If you use your handheld to go here: 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. knowledge with the sniper efi setup. 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. The car would idle, I could hit the gas rev the car up and it ran great I also noticed two nice black spots on my garage floor from the exhaust. 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. You can re-enable this after you have completed this idle speed adjustment process. Please advise. The fact that it ran so (at times) with 90+ PSI fuel pressure is a testimony to the Holley's closed-loop technology. The motor has 376hp at flywheel and the car is a stick shift. If your RPM is 2000, your TPS is 0, and your IAC is not closing, then there is some problem. Do please let us know what you find out! 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. We do that but most places don't. 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? Copyright 2022 Holley Performance Products, Inc. All right reserved. 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. 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. So something is triggering the ECU to be in Open Loop. I didn't find your site until I was having trouble. One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. Don't try to correct for the fuel. 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. Again, I would lean on that solution to let the vehicle drive/learn before you try to "fix" anything. But he kept having problems so eventually he did a complete check and then he found the problem. My problem is low idle. They tell you to ask call Holley. I keep doing that with the same result. Earl's Mechanical Fuel Pressure GaugeI could use that for a quick troubleshooting for 1/3rd the cost of the Holley one. So glad this was helpful. If either of these is not the case it must be remedied.After you have done this then you might want to involve Holley Tech Support about the TPS, or it may be easier/faster just to visit the local auto parts store and pick up a new TPS and install it. % = 49 It runs perfectly fine other wise. Ensure all your sensors are displaying proper values. I did buy the Sniper from you guys and the service was fantastic. 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. 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. I did change the -40 thing also. Key, I believe, in this success is solid connections, resistance-free signal and ground paths, and solid RFI rejection. 2. It could be, but that seems unlikely.Instead, you need to look at the basics. It's called tuning. Drives just fine but won't stay running unless I keep my foot on the gas. For someone in your position, it will become an indispensable tool in your tool box. Hopefully replacing the pump again will resolve both issues. )Then look a the datalog and find out what TPS ROC and MAP ROC is most likely to cause the problem. Also if I give it a ChrisI finally got everything resolved. Really appreciate the amount of learning im getting off here. The window you saw in the image above pops up. it will jerk and rpm will go up and down and AFR will be around 20 : 1 or more or less. normal city driving, I no longer have other problems I had with the original 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. I have double checked everythingincluding fuel pressureand have followed the directions to a T.I plan on trying your 10 step process as soon as I get a chance. Idle was around 1000 mark and iac 0. I have changed my roc/tps to 7 from 15 but that only took me out of learn mode. I used the Casper's Electronics 108103 splitter and carefully soldered my connections. Use the idle speed screw to set the idle at a comfortable warm-up speed. 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. I drove it a bunch more yesterday afternoon/evening and the same thing happened several times. If you go too low then it may stumble or even stall when coming off of throttle. What an amazing site you have here. If you go too high then the motor will not return to your target idle when you come off the throttle. Idle was back to normal but iac was at 0. Definitely would have went with you guys. Often, folks will say, "I did everything you said. Turned it off and on again. And all too often we don't take that extra step of using a piston stop to ensure that the timing pointer is on zero when the engine is truly and exactly at top dead center. If the TPS reading on your Sniper EFI System does not reset to zero that is a problem that needs to be addressed. I installed another return spring for the rear plates problem solved instantly. Hello Chris. View Holley Sniper EFI Self-Tuning Kit - Shiny Finish. 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. Technically it is a warranty-voiding maneuver so proceed at your own risk. Does anyone have photos of this additional return spring they installed? The Sniper even has a feature that allows it to use the idle timing to control the idle speed. Going in the direction you did (higher) is going to reduce the acceleration fueling that the engine sees. Target AFR at idle is 13.8%. When you open your IAC to 30% you are naturally going to have a high idle condition. I have a Holley Sniper EFI with HyperSpark ignition. The small rubber plug had a leak. Coming home from work today it was much warmer and took a little longer due to traffic. issue. My issue is that the TP% will not reset with key cycle and its idleing at 9% TP. I had a customer recently with a high idle problem that he eventually traced to pad plug on one of the vacuum ports. 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. So this is my issue ( I did just email Holly). There is no real mystery here. To start viewing messages, select the forum that you want to visit from the selection below. Only show this user . I think that your Sniper system is working fine but would definitely check ouf the fuel pump. This curve runs fom -40 degrees to 260 degrees, and gradually reduces the RPM along that range. Even at 0% it's sucking a bunch of air through the IAC port. 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. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. The broad consensus has been that the Sniper is an amazingly straight-forward install and starts and tunes as expected. I will a, Scott has been very helpful and informative on guiding me through the purchasing and installation of my terminator X max system. Some advanced conceptsIf you have the Sniper Can-Bus to USB Adapter, you can connect your laptop, open the software to the learn table, and get a visual for where in the table you are experiencing the lean bog. It only lowers to 2-6% when I take my foot off the gas. This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. The IAC should display a 2-8% to bring the idle up to the actual target. 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. Turning off and then on again, the engine returns to normal. It has a lightweight centrifugal spring kit installed so I reach total timing around 2500 rpm. It sounds a little different from mine, since it commands a 1300 or so increase intermittently. Thanks for any help. If you did not rotate the distributor to set the actual timing to 15 that might be the only issue. Now it registers zero and I have good idle but it will not register until it hits 60 and up. If your TPS has snuck up to 2% then your IAC will be at the hold position, which by default is 30%. When I put it in park the idle RPM was 2100-2200 each time. Or alternator? If I adjust idle screw out to get the tps to zero or even 1% the engine will not idle. You can find those settings here: Handheld: Tuning > Advanced > Advanced Idle > Rampdown, Software: Idle > IAC Settings > IAC Ramp Down. TPS 0. 90% of time with engine hot. )Since this isn't a consistent issue with all Snipers that tells me that different IAC settings tend to make the whistle. IAC percentage is 5 to 10% when idling with fans on, What you're experiencing is the delay time between the ECU sensing the additional load and the IAC actually increasing the RPM. This is normally used as an A/C idle-up circuit. Seems to behave more better now. Free ground shipping regardless of order size! 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. These problems will go away when you do that. Worst case you'll have a spare on hand, and if the TPS is faulty you will have solved the mystery. 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. :-). FYI: Car is a 1970 Mustang 302 Ford Racing roller motor. 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. One of the best Ive seen so far. I received from the controller manufacturer greatly understates (at best) the repeated failures of others I know personally who have tried and failed. Your mechanical advance will naturally change the timing a bit but it should be fairly close. That will at least tell you something. You might have a bad O2 sensor, really bad exhaust leak or a problem with the ECU. Ilike a few othersam having idle issues. Just thought I'd ask as there isn't a lot of info out there. I go into much more detail about that in this article on startup tuning. 400 engine, C6 3 speed automatic, with standard canister coil for ignition, and We've already tried adjusting the Acceleration Enrichment chart in all ways, going up and down, RoC Blanking, everything, it has no effect. Its timed to 36 degrees. any advise would be appreciated. I hope everyone enjoys this v. What can I do? I do know that the reference angle is 57.5, the inductive delay says 100.0. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! I'm new to EFI and have no idea what to try next. If you have an installation or start-up issue that is nagging you then please use the comments section to reply and we will gladly provide more information that we hope will be useful to you. It's pretty hard to get the header tubes glowing at idle with a lean AFR. The fix? Your comment doesn't imply any sort of problem that would make me give up on idle timing control. After a complete cool down it will do the same thing. I started with right after I first adjusted for 2% IAC and took pics about every 30 seconds over about 2 minutes. It is always best to get the base map as close as possible before adding acceleration enrichment. The Sniper will be controlling the timing so it will be based on a multitude of factors. The idle is 1350-1400 with the idle screw at initial contact. The car cruises fine, and if I was to keep idle at 2000rpm the issue wont happen, its only when the car tries to ramp down to idle position.Thank you for your help, any advice would be appreciated.Thank you,Eric, Whenever we see the AFR go to "Heating" that is an indication that the ECU has been reset. Get that thing installed and you're going to know a whole lot more about what's going on. Seems like its too slow to grab idle when ac kicks on. 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. I have an entirely separate article on Solving RF Intereference Issues. 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. If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. Holley EFI Electronic Fuel Pressure GaugeI think its a little ridiculous that I cant see fuel pressure on the display even though its measuring it but whatever. 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. I think that this time around you will find that it starts and idles really well and only gets better from there. The problem was RF interferance . But nothing beats a good solid gut-check (Do this while you are cranking.) 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 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. In that case, and if you have an EGR valve, I might be suspicious of something going on there. I am Japanese who attached Sniper EFI. Ok, so there are a couple peculiar things going on here. The hold position is part of the response that keeps the car from dying when you come off the throttle. The throttle plates are misaligned. In the setup, I set the hot idle for 850. It sounds like you need a bit more of a fuel squirt on acceleration, Brett. Then your low idle problem will go away. Since a key cycle resets it to 0 and out to 30 or wherever I can get it to fire up on the Could be a bad IAC motor, replace it and see if that solves the problem. idles good, runs amazing. Jump on board now! Try it! Give us a hand! That way you can get into that part of the table that needs tuning, and you can watch your learn numbers grow. Nice to meet you. The IAC is hanging open and not really at 0. It is a common one. I believe because the TPS is not registering. Any suggestions? I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds An under-sized filter will allow part- throttle operation but fuel pressure will drop at WOT and run very lean - perhaps surge under power. 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. He has walked me through every question Iv. But before you adjust the ECU to lean the idle out, first confirm that your fuel pressure is right. Copyright 2022 Holley Performance Products, Inc. All right reserved. Has a good size camshaft cant find any vacuum leaks. Always had to set idle above 950. First, check to make sure that the IAC is properly mounted and connected. It might be necessary to insulate or re-route your fuel lines if this can't be solved any other way. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. check out the. 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. 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. I would suggest at that point you need to contact whoever is providing your tech support and find out why the default values are not working for you. We will definitely be sticking with Holley from here on out for future retro-fits. That is a good thing.I don't have a specific target RPM but always encourage automatic transmission users to bias the idle just a tiny bit higher than what you might otherwise. Then it started behaving oddly. Usually it wont stay on 0% very long and soon changes to another number like 1 or 2%. We are using Target AFR of 9.0: 1, Fuel Base approximately 40% higher. 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. Generally, one of two things: a stuck throttle or noise on the TPS signal. I took some pics of the sensors page this morning after the car warmed up. You have to remove all hoses in order to debug the problem. 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. Between the kick down and the return springs on the throttle body the pedal is so hard to push it's pretty much a jack rabbit start every time from stop, it's almost undrivable, any suggestions on what I could do?thanks for help, I've tried both Holley's tech lines for close to 2 hours with no answer! 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. I would continue checking the electrical connections along the fuel supply. Price Point: $$$. At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. Ensure that the secondary linkage is completely closed (both visually and manually.). The fuel pump is mounted under rocker panel as low as possible and far away from any heat. Except at idle. Confirm the placement of all wiring, ensure that the WBO2 sensor is positioned properly, etc. However, I have never found that to be the case. So the issue Im having is low 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. I had a customer who struggled to understand that. Cycle the ignition as instructed by the handheld and then navigate to the distributor setup screen. Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to Idle : IAC Rampdown : IAC hold positionChange this by maybe 2% in either direction. I also noted that after some time, I could change those values as I saw fit. 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. This may require shortening or lengthening a rod. (Plus they it just looks way cool in your engine compartment!) New install, when in setup wizard TPS says 90 percent and I checked the linkage and butterflies. Mechanical Fuel Pressure Gauge on the inlet of your Sniper, now is the time. Please give this a try and let us know how it works! Did you find this enlightening? Your suggestion to remove the PCV valve is just for diagnosis purposes, right? Bryan McTaggart 02/28/2023 news carburetor setup, but it does blow when I can't jump on the highway like I use At low levels RF interference will often reset the ECU so quickly that the engine will not stall. That is the default "Clear Flood" TPS setting and turns all fuel off until the engine cranks. Check the Distributor Tach Connection to the EFI. Im in Australia, so stuck the sniper on a 355 Holden engine with CD box. 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. 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. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. Start with the most gradual throttle input you need to launch well, then slightly increase until you feel some stumble. 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. Sniper EFI Tuning & Tech. My car will not idle right until it gets to around 130 -140 degrees. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. The noise is definitely coming OUT of the throttle body. The person I bought it from said he never could get it to run for more than a few seconds. Thank you in advance for your help and providing us rookies with your 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 truck off. So, clearly, the "No" answer is wrong. You could install the Holley Dual-Sync Distributor and let the Sniper control your timing. hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I Idle quality is great, RPM is good, sometimes IAC is jumping around from 35 to 60. However, it is a good question so I thought I'd throw a few bits of info out there that I think might help.First, I believe that you may have a basic misunderstanding of what is being referred to sort of generically as AFR. such high fuel pressure. Comp. 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.