The manifold pressure increases with the throttle opening but the RPMs are still low. After speaking with Holley Tech Support and Tech Support from where I purchased the systemthey decided to replace it. I have installed my Sniper and the car runs great. 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. You advise would be greatly appreciated. This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. The Sniper EFI system looks at the closed-loop fuel compensation required to reach your target AFR. 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. I keep wondering how it was running so good with The fuel pump is mounted under rocker panel as low as possible and far away from any heat. But before you adjust the ECU to lean the idle out, first confirm that your fuel pressure is right. 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. 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. This can cause the engine to run rough and may even lead to engine damage. MAP Sensor. Contact whomever sold you your system or Holley directly. I would only play with this if you are finding that the other adjustments I suggested aren't working. Even then, recognize that over time the IAC will need to be readjusted to compensate for minor changes that will cause it to drift. This is normally used as an A/C idle-up circuit. One of the signs of a vehicle with a rough idle is a faulty Idle Air Control (IAC) Motor. 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. If you get into the practice of hearing all three of these sounds you will know if you have a problem even before you turn the key to crank. :-). Seems to be working. Overview. And thanks again for taking your time to answer these questions. If you're having issues with your Holley Sniper IAC getting stuck at 20, there are a few things you can try to fix the problem. If I go any more it will ping. When I turn it off and try to restart it just cranks. There's still a very small amount of airflow that squeezes past a closed IAC valve; it's that venturi like sound you're hearing. 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. 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. Bolt on 4150 Flange Carburetor Replacement. They always responded to my questions with guidance that helped me choose the right system for me. I'm so glad you found this helpful--that makes my day!Don't get too concerned about the specific learn percentage. EFI System Pro had everything I needed for my EFI upgrade. I installed Holley Sniper on three other Mavericks here in Brazil and the problem also exists.I did not make any changes to the parameters, only on Target AFR and the correction on the Idle Speed Curve chart. You could install the Holley Dual-Sync Distributor and let the Sniper control your timing. After only running for about 15 minutes or so the system starts to fail stalling the motor. Look over all of your vacuum lines and fittings. If you do find you have RFI issues then I've written an . Also if I give it a That is not the way to go. Price Point: $$$. check out the. 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! I certainly appreciate your frustration (as well as your wife's!) When the system is up and running the fuel pressure regulator inside the Sniper is making a rattling sound like a shaking a paint can. But, whether your vendor provides you with tech support or sends you to Holley, I'd start by getting them a data log and asking for some insight. 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%. You are aware of the idle-up problem. When I am coming to a stop, the rpms will hang at 1200-1500 rpms. Is there any chance that your timing has changed since you installed your Sniper? 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. Your task will be to find that. 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. And if you're going to go this route I'd recommend that you switch from "Simple" (3 A/F targets, one each for Idle, Cruise, and WOT) and go to the 2-D Table Holley documentation and videos didn't work and the $300 I paid for "expert" tuning didn't work either. If the issue persists, you may need to replace the IAC. Please give this a try and let us know how it works! Its timed to 36 degrees. 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. You just need to go back through the IAC adjustment procedure now that idle timing control is enabled. Chris, I recently installed my Sniper and have an intermittent idle problem. 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. Any suggestions? It started right up and we did your idle control fix and all is good at idle. However based on your reply I connected the Fuel Pressure gauge and Camshaft is M-6250-B303 .480 lift intake & exhaust, duration at .050 is 224 degrees for intake & exhaust. )Take a look at your AFR during the starting process. If you haven't installed a I had HIGH Idle issue and fixing this curve FIXED the ISSUE --- THANK YOUCan you explain what "Current Learn % means, after finally fixing the idle problem this % jump from -1 to -30% in about 5 minutes at idle with CTS @ about 170.Also when starting the car at hot the engine goes to about 2300+ RPM for a few seconds then crashes down to my Hot idle speed of 950 -- bounces a little and then smooths out. Genuine Walbro fuel pumps are virtually bullet-proof. When you have the issue you should disconnect all hoses and plug the ports on the Sniper. 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. I notice at 2-3% tps the iac is 18-25% and it stumbles, when the iac gets to my hold position of 30 it stops. What I can't explain is why your TPS is acting so randomly. Hello Chris. If I keep the rpm's up it does fine but my clutch can't keep up with this for long.Also when I cover the IAC port the engine dies. (Note: in the original version of this post we had a section about checking the idle speed curve setting. First, check to make sure that the IAC is properly mounted and connected. School's out for spring break this week though so I'm covering for employees on vacation. 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 I were there in person I would test the function of the IAC (see this article.) 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. The biggest issue is these problems are intermittent meaning they do not occur all the time. I pulled over and turned the car off and then back on. Do you have any clue? Yes, you are correct. 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. 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. After 50 on the throttle position I'm not sure if the whistle goes away or you just can't here it anymore. Try it! It works instantly for him.If that fixes your problem then you have a starting place. I would continue checking the electrical connections along the fuel supply. such high fuel pressure. It appears that I could now use the dongle and a laptop to custom tune for idle issues if needed. And yes, monitoring the fuel pressure is the right answer. Has a good size camshaft cant find any vacuum leaks. I think that your timing is too retarded. 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. But another thing to consider is adjusting your target A/F ratio. 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. Generally, one of two things: a stuck throttle or noise on the TPS signal. So I had my Idle set up perfect, with idle timing control off and engine hot the IAC was right at 2-4%. 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. If you go too low then it may stumble or even stall when coming off of throttle. Hey Chris! After a stall the car will restart but will be in a high idle. At some point you come upon problems that evade the easy answers and this is a good example. 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 followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. The first thing I'd do is check your fuel pressure with a gauge like this. Save Share. Tried that and it didn't work? That If it creates an issue (not normally the case) then you'll know. 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. 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. They are prone to be inaccurate. If You'll be amazed at how much of this just "goes away" when you drive it enough. After manually making the sensor go through the full range a few times, I reinstalled it and now my TP will read anywhere from 0% to 4% when I key on. A problem since day 1 - YouTube Leave a comment if you've had this issue and how you resolved. I was looking at a data log from my truck earlier this week and noted that at idle my IAC was zero. Shut off the engine, ensure power to the Sniper is switched off. 680-700.I can't find any reason other than it looses where it is in the firmware with If I cruise down the road at lets say 60 mph and lay into it, she will take off and go. I installed the Holley gauge you suggested in another thread at the fuel input to the TBI, and the fuel pressure is constant around 64 according to the gauge. 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. If you have any questions about the car/setup let me know. other things that might cause the idle to faulter, but this is a good start. applies here because it is so important to realize that just because the IAC 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. Thanks in advance for any advice. 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. And so glad you guys are enjoying the Sniper EFI system. In your case, however, I think you're close to getting it running. issue. Featured Products EFI - Fuel Injection $2.59 - $6,499.95 2179 Products View Parts Sensors 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 you go the other way then you might find that the IAC zero's out when the fans are off. The throttle blade adjustment is at 2-6% at hot idle, and with warm engine 185F. 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. The problem was RF interferance . Another suggestion is to add an extra turn to the spring built into the linkage to increase the closing force on the throttle shaft. Have you confirmed your fuel pressure at idle is 60 PSI? After a complete cool down it will do the same thing. (Plus they it just looks way cool in your engine compartment!) Car was running great initially. Put a strong piece of tape over the IAC breather hole--duct tape or something that couldn't possibly be sucked into the throttle body. As I would slow down for a stop sign or stop light, the car would run really rough and the idle did not want to come down. 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. What could be the cause? Thanks. AGAIN This is Intermittent meaning on a recent trip I stopped 3 times and issued occurred once. 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. Copyright 2022 Holley Performance Products, Inc. All right reserved. Sorry for all the questions, new to the efi world. I did check for the lightning under the hood but all was well. 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.) See these. The engine makes very low vacuum at idle. It'll start & run till it's warm, then when I try setting the IAC every time, I try getting it between the 2 & 8% it quits. You might have a bad O2 sensor, really bad exhaust leak or a problem with the ECU. You are looking in the right area but I would probably not change the ROC blanking. When I removed the tape and started it again, it was idling at 1400-1500 RPM and sucking a bunch of air through the IAC, even though it showed 0% on the sensors screen (pic attached). 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. Hello Chris. Is there away to lean the idle out? I never had a problem with this. $107.95. 30 minutes later CTS reads 161, start engine Idle is jumping from 450 (almost stall) to 1500, IAC is jumping all over 10 90. A common issue we see is a result of poor fuel pump grounding running a eyelet from the pump ground to a rusty or painted surface. Use the idle speed screw to set the idle at a comfortable warm-up speed. 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. i would have been happy to answer there. Copyright 2022 Holley Performance Products, Inc. All right reserved. I'm Having trouble with the Sniper on high Idle. At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. I have replaced the IAC motor and the problem remains. Fortunately, I have an article that goes into this in some detail. As I said I didn't buy from you so you don't owe me anything. Then, the next time I cranked it, the idle went high and won't come down!" Next, reach down into the secondaries and push the butterflies closed. 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. While it is not mandatory, I recommend the Sniper EFI CAN-to-USB Adapter to move the data between your Sniper EFI and your PC rather than trying to do this via the SD card. Holley Sniper IAC Surging???? Again, I would lean on that solution to let the vehicle drive/learn before you try to "fix" anything. Note: The IAC breather hole is the roughly 1/4-inch triangular hole that sits above and between the secondaries. At that point the tps is pretty high, then shut the ignition off, pull the tape restart the engine and idle goes into hold mode and idle is through the roof. I installed the Sniper on my 1978 Ford F-100 with a small block This is very disappointing as people love to hear the motor while the hood is open.Thanks Jon. 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. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. Do please let us know what you find out! sniper Installation If you're installing a Sniper EFI system and almost ready to crank it over for the first time, this is the video for you! Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. Anyway I have a 327 sbc in a 1987 Monte SS with a T5 5 speed and 3:73 posi rear. 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. After much diagnosis, I ended up replacing the intake manifold gaskets. If you are idling at 2100 RPM (based on a default IAC Hold position of 30%) and your target idle speed is 900, then the ECU is not going to try to idle down. I 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. At idle my IAC is 3-4, AFR around 13-14, TPS is 0, timing 15-17. I can adjust at 160deg, but my fans turn on at 180deg. One of them might be faulty. I would start by removing the progressive linkage. Maybe here will work better ?Sniper High Fuel PSIMy fuel psi is over 90 according to a brand new Auto Meter pro mechanical gauge tied in at the inlet to the Sniper using an AN adapter.I did the search function on here and found a similar high PSI issue that was fixed by clearing the return line.I have checked the return line hose for kinks and have removed it and blew thru it without any back pressure. (If you do this you will need to reset the -40 degree setting mentioned at the top of this article. Have a look--I think this is going to allow you to fix your idle problem. What you are experiencing is rather common. Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. Try it! I can get it to fire up on the I think in some of the Wizards with the handheld it doesn't use 57.5 as the default. Your mechanical advance will naturally change the timing a bit but it should be fairly close. Bolt-on carburetor style EFI for your classic car or truck. 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. One of the best Ive seen so far. So glad this was helpful. The team at Holley has designed the perfect solution for your problems. Also, I was seriously rich at idleso rich it hurt your eyes. 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. This happens no matter how much I adjust the idle screw. I' m going to put the 3rd new pump this coming friday. I have a bone stock 350 that I installed a Sniper on and had the same whistle noise, presumably from air going past the butterflies. I ask because I'm using a PCV valve with my Sniper and have random idle issues as well. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. This only happens when coming to a stop and the idle is ramping down to the set idle RPM. It is simply for the benefit of the user. Since your target is probably more like 700, and since 2400 is way over 1700 RPM, it's going to leave the IAC in the park position.Buckle down and find how air is getting into your engine. And your understanding of how the throttle position affects idle is exactly correct.