It sounds to me like it is way retarded.In the event that the timing is right then take a look at your AFR--the actual AFR, not the target. 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 am having an issue with the IAC on the Sniper. May God's grace bless you in the Lord Jesus Christ. :-). The tps has slotted holes, can you adjust it to get to zero? and if you do run into any problems then, yes, the plethora of tunability adjustments available through either the handheld or the Sniper Software will certainly be enough to get you right where you need to be! Is that normal? Now it's at 5% on a big cam 440 Mopar. close to idle with the IAC between 2% & 12%. 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. Thanks for the great question! )So before I hook up another gauge to see if the Auto Meter is bad (assuming I can find a 0-100 test gauge in my shop). :-DStill, I hate to leave someone hanging so I'll try to help. Always had to set idle above 950. I have certainly seen this before on other fuel injected vehicles when hot. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. and when I close the IAC's hole with his finger, the engine is normal.The data on the touch screen I see are:AFR, A / F = 35.6 The person I bought it from said he never could get it to run for more than a few seconds. But as you see from the recent revision I did above you seem to be having a fixable issue. Since the shield was put on, not a single problem, not one. 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. I guess we can't have everything. If your fuel pressure is at or about 60 PSI then visually inspect the barrels of the throttle body while having someone key on the Sniper. (It should be at or near 60 PSI at idle. You may have to register before you can post: click the register link above to proceed. But if you can datalog the bog you can know much more precisely what is happening. 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. I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. Once it commands that high idle I haven't found anything to return it to normal, other than shutting it down and restarting. Use the idle speed screw to set the idle at a comfortable warm-up speed. I chased that gremlin for about three weeks and was convinced I had a bad throttle cable. I got it home, checked it all over, everything is hooked up correctly. Don't be surprised if one or the other is slightly open. I have seen this become blocked with debris / dirt in the fuel system and cause a high fuel pressure condition . around 45 mph it bogs down, catches itself, bogs, catches, bogs and catches. If You are aware of the idle-up problem. But, if the idle is so high that it is making you crazy then you might try dropping that number just a bit. Price Point: $, Advanced throttle body injection systems capable of transmission control and more. I have heard some guys complain that the idle is too good and they can't hear their cam anymore I'm kind of like that. Sniper is still learning so it will continue to improve.Second, you may have heard the phrase, "correlation is not causation." After pumping the pedal a few times at different times it dropped to zero and started to work. I am new to the EFI scene but want to learn. 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. 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! your IAC is at zero. Price Point: $$$. Have a look--I think this is going to allow you to fix your idle problem. 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. I have never seen issue when CTS is below 120 degrees. itself out and hold idleeventually stalling. There are six different acceleration enrichment tables that you can tweak and that may be the way to go. If more info is needed just ask. When you first posted this I had no idea how to respond. The engine makes very low vacuum at idle. I certainly appreciate your frustration (as well as your wife's!) If the ECU has not spent some significant time learning yet, I'd recommend going back through the setup wizard and getting everything back to default. This will let you know at a glance if something is going awry with the fuel pump. Im not sure what its doing, have messed with after start fuel, fuel at cranking. You can drop it down and you will find it will behave more like you expect. When I put it in gear, it drops so low that it will stall if I don't add throttle. I have an adapter on the manifold for squarebore to spreadbore and then a phenolic spacer. 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. You advise would be greatly appreciated. Doesn't want to start, runs like crap. Then you can take a close look at the IAC and see if it is opening. Take a drive and stop somewhere for 30 minutes, CTS is 170 when engine was shutoff. 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. Any help would b great. Throttle Tip-In puts you in a part of the fuel map where you stay for only milliseconds at a time. I'm going to jump out on a limb here and say you either don't have adequate fuel flow or pressure. I know this is old, but I bought and installed a Sniper kit in 9/18. Eventually the IAC will drop back to zero, I'll readjust it to 850 RPM & 2-9%, and then watch it steadily climb again. The Sniper EFI replacement throttle body for Autolite 1100 carburetors will be right at home on most early in-line 6 cylinder powered grocery getters or weekend cruisers. Enjoy your Sniper! Take it a step at a time. This is a mighty big subject for a blog post reply, I should probably start doing some videos on this. EFI System Pro had everything I needed for my EFI upgrade. To do this, open up the Initial Startup gauge screen that was used in section 17.0. I've not heard of any others with this exact issue so I don't think it is a common problem. I, too, wish you'd bought your Sniper from us! 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. I managed to get the IAC down to around 0% - 8%is this good? I've been having problems with my sniper efi just shutting off. One way is to very carefully watch the handheld monitor, and that may be adequate. I' m going to put the 3 rd new pump this coming friday. The TPS will go red with a -15 and the AFR reads heating for a split second, then the idle kicks up to 2000RPM. 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. I will turn it up some more.Is this something that the ECU will learn? Your comment doesn't imply any sort of problem that would make me give up on idle timing control. Thanks again Chris, your help has been invaluable.If anyone is considering going EFI, Chris is the man to chat with. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. 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 have tried your 10-step idle adjust and ive adjusted the idle curve. Just getting it to act right at startup is a struggle. I can get it to fire up on the Hi Chris , greetings from Down Under (AUS) Just a note on the hi fuel pressure issue . Your closed loop compensation is adding a full 50% fuel. Throttle body mounted ECU - no extra boxes to mount. Get On The List for Emails Straight From Our Pro? I think that a great number of the challenges that Sniper EFI System Owners face are brought on themselves by getting into the control settings before the system has really had a chance to learn. First, recognize that the amount below your target where you set the hard idle will be different on different engines. Interesting situation you have. You can disable the idle spark control at the locations below. The broad consensus has been that the Sniper is an amazingly straight-forward install and starts and tunes as expected. It didnt do this with the carb on it. If you remove the air cleaner entirely and the whistle continues then you can rule that out. As you have noted, each time the idle goes up. 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. Yes its at 95lbs, needless to say he promised a new regulator would be in the I did change the -40 thing also. If I block off the iac with tape , I can get it to somewhat idle, but its not consistent. 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. This car has never idled under 900 without stalling with 3 carbs and does the same thing with sniper edit. If they are closed, check the primaries. Bolt-on carburetor style EFI for your classic car or truck. About two minutes after I get it set at 850 & 5%, it has progressed to 100%. What could be the cause? We are running a Sniper on my mates 355ci small block V8 & so far he is very impressed ! Now, in my lifetime of experience with Holley ECU's that seems unlikely, but this guy sounded really sharp and had nothing to gain by convincing me of his dilemma. Then it will ramp down to 1200 but will not return to idle. I recommend you have a look:https://www.efisystempro.com/efi-pro-hangout/holley-sniper-efi-instruction/solving-sniper-rfi-problems, I recently purchased your fixed linkage to open primaries first and the throttle linkage extender to also get a smoother pedal. Please check your process again and see if you can see very specifically what is not working correctly. The Street/Strip and race cam setups tend to be too rich initially. I'm running a 408 sbc. If you do find you have RFI issues then I've written an . Hopefully replacing the pump again will resolve both issuesWhoa. idles good, runs amazing. My guess is a faulty IAC since it is intermittent and I have not done any setup changes. It is working fine when you restart the car, controlling idle perfectly at 8 steps open so it is unlikely to fail when the car warms up--or correct itself instantly when you restart it..So, if you don't have any vacuum leak, and the throttle plates are fully closed, the only thing I can guess is something is causing your ignition timing to change. Therefore The iac will always be at 10% now, correct? It works instantly for him.If that fixes your problem then you have a starting place. 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 have a feeling it's something simple but I thought I'd ask you first before I inadvertently change something that affects other areas. 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. I think that this time around you will find that it starts and idles really well and only gets better from there. 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. (If you do this you will need to reset the -40 degree setting mentioned at the top of this article. These problems will go away when you do that. The warmer the motor, the higher the idle will be at this point. 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. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. Have you confirmed your fuel pressure at idle is 60 PSI? Hey Chris 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. 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. The data that you provide shows that you have at least two problems. The "Gauge Text" is what would be shown on a 2-1/16 gauge or the Avenger handheld display. After it starts it idles around my 960rpm setting + or - 100rpm. Purists will sniff that these are not accurate to the tenth of a PSI. This increased idle speed is triggered by grounding the orange wire in the 10-pin I/O harness. So something is triggering the ECU to be in Open Loop. Otherwise, if removing the air cleaner eliminates the whistle then try to use a thicker gasket or try lightly greasing the gasket. Chris, I recently installed my Sniper and have an intermittent idle problem. Drive great and idles perfect at stop signs. No big deal, just time to re-adjust! 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 When I covered the IAC with my finger, the RPM dropped so low it stalled. This value is itself enough to raise the idle a bit. Seems to be working. Even 50 RPM can make a difference in how much impact the transition to Drive has on the idling engine's ability to stay at a fixed RPM.I would not recommend it in this situation but anytime a "kick" in idle speed is desired that is easily done by setting the kick value in Tuning > Advanced > Adv. What can I do? Mechanical Fuel Pressure Gauge on the inlet of your Sniper, now is the time. Technically it is a warranty-voiding maneuver so proceed at your own risk. Thanks Again for your help. 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. They are prone to be inaccurate. Let me be perfectly clear: If your engine will not drop below 1350 RPM with the idle speed screw turned all the way out then you have an air leak. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. How can I adjust the startup speed down to about 1400 RPM? With the engine still idling high park, set the brake, open the hood, and remove the air cleaner. 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. No problems with either cold or hot starts. I had a customer who struggled to understand that. If you haven't confirmed that they it is worth checking. Hello Chris. This may require shortening or lengthening a rod. Nice to meet you. So glad this was helpful. I would recommend that you call first thing in the morning, as they tend to get quite busy during the day and wait times can get long. 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. This is actually more troubling than the sound you originally described. 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. Once you have done this the challenge is to create a datalog that includes the ":snap" you describe. The symptoms I had was a low cold start idle and going lean coming to a stop. Its just at low speeds, not sure if its loading up or leaning out. Thank you. Could be a bad IAC motor, replace it and see if that solves the problem. Or is there something else I should 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. There is no real mystery here. 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. And your understanding of how the throttle position affects idle is exactly correct. 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. I.e. When you experience this, before you touch anything or shut the engine down, first look at your TPS and your IAC. Thank you for this guide on setting IAC. It starts cold fine, its just when its hot. If that happens then follow my 10-step process shown above. Data logs show no EMI/RFI. This page was generated at 12:25 AM. 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. 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. how long does an embezzlement investigation last,