This is a mighty big subject for a blog post reply, I should probably start doing some videos on this. By the time I was near home, the idle in Park was 1050, IAC 0. mail today. The distributor was loose. Could the IAC be broken/malfunctioning? Covered the IAC port and set idle for 850 ish. Bolt on 4150 Flange Carburetor Replacement. Take a drive and stop somewhere for 30 minutes, CTS is 170 when engine was shutoff. My Sniper is 99% great! issue. The "PC Text" indicates what will be shown on the PC/Laptop data monitor or data logger. These problems will go away when you do that. You can adjust this number up or down but there is really no need to change it unless the car is stalling.The sucking sound is just what happens when the Sniper EFI System is paired with certain intake manifolds. And, hopefully, within those degrees you will find a place where you don't get the whistle. 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. 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 used the Casper's Electronics 108103 splitter and carefully soldered my connections. I would only play with this if you are finding that the other adjustments I suggested aren't working. The engine ran so good, I would have never suspected the Fuel Pressure to be an Part# 538-13. With an assistant pressing the accelerator, you need to make sure that when the accelerator is pressed to WOT that the throttle blades are fully opened, and when accelerator is lifted the linkage is fully at rest against the idle speed screw. 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. I'd recommend you contact Holley Tech support to get their input (1-866-464-6553; call early for the shortest wait times.) As I have it set right now, my idle at park is in the high 700s and my desired idle in gear is set at about 700 cold (80 degrees) and gradually lowers to 590 once engine temp reaches 160 degrees. If they are closed, check the primaries. 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. Im thinking a faulty TPS. It will learn the fueling eventually either way, it's just that one might get you there a little faster.If the idle is fine at start-up but then increases after you depress the throttle then you might need to lower your IAC Hold Position a bit. If your mixture is too rich, it means there's too much fuel and not enough air. A good example of why it's so important to run a good pre filter in the fuel line. 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. And yes, monitoring the fuel pressure is the right answer. I hope everyone enjoys this v. 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 installed a sniper efi system on my 1969 Camaro. NOTE: Do not attempt to set the target idle speed and IAC position until the engine is above 160F! See these. No big deal, just time to re-adjust! You may have to register before you can post: click the register link above to proceed. I recently bought the car with the EFI system on it. EFI Systems based on Holley's world-class Dominator and HP ECU's. Have you confirmed your fuel pressure at idle is 60 PSI? Ive played with the timing on this thing multiple times.Car was fullly restored last year. My IAC and TPS show zero when it does this. 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. Idle Tuning is a very important part of tuning any EFI system, especially our self-learning units like Sniper or Terminator X EFI. check out the. I would not expect that an electric fan would create a noticeable load on the engine but if it did then you'd want to set the idle screw when the fan was not running. check out the. the issue I would suggest you take a look at that if you haven't already. I've tried repeatedly re-creating the scenario in hopes that the E.C.M. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. We're having trouble with a Ford Maverick 302 V8, using ethanol. The problem I experience is that after driving for about 10-15 minutes, the car starts idle to high. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. I chased that gremlin for about three weeks and was convinced I had a bad throttle cable. Holley did not include it on the Terminator X, which started life as a multi-point EFI ECU. I ask because I'm using a PCV valve with my Sniper and have random idle issues as well. 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. Hope this helps! It sounds a little different from mine, since it commands a 1300 or so increase intermittently. To get it to idle the tps is at 2-3-4% even with linkage disconnected and a return spring installed. There are six different acceleration enrichment tables that you can tweak and that may be the way to go. It meets the target idle perfectly in either but if I lightly stab the throttle it tries to stall after slightly revving. Bryan McTaggart 02/28/2023 news I have driven a stand-alone transmission controller for the 4L60E in my (then) Sniper-equipped '95 GMC pickup using the Sniper TPS with complete success. The biggest issue is these problems are intermittent meaning they do not occur all the time. To be honest, you sound like an ideal candidate for Sniper ECU ignition timing control. However, I did have another fellow who contacted me that claims he went through three units before he could get one that would talk between the ECU and the Monitor. 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. In fact, it is those users who seem to end up most impressed with the system. )Take a look at your AFR during the starting process. Once you confirm the operation of your IAC then it's time to read my article on Solving RFI Problems. I' m going to put the 3 rd new pump this coming friday. The person I bought it from said he never could get it to run for more than a few seconds. The Sniper Quick-Start Manual provides the following instructions for setting the idle. Capability Range: Professional Sometimes it sounds like it wants to crank at the start but runs out of gas. I have a 406SBC that does most everything right with this sniper setup. check out the. Thank you very much. The latest was changing the power brake booster.Today I drove it to work and no issues at all. I tried adjusting my IAC up to 10deg in both directions with no change. Then you can take a close look at the IAC and see if it is opening. When I put it in park the idle RPM was 2100-2200 each time. 680-700.I can't find any reason other than it looses where it is in the firmware with Idle : IAC Rampdown : IAC hold positionChange this by maybe 2% in either direction. Try it! They also worked with me on a sale I missed and price matched those parts. is train the system or there is actually something wrong.I do love the system at 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. There are a few tell-tale signs that can help you diagnose the problem. 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. The weather in Ct has finally improved and I have put about 60 miles on the car with the Sniper system. If it is then something is commanding the ECU to open the IAC. When I put it in gear, it drops so low that it will stall if I don't add throttle. Next, clean the IAC and all related parts with brake cleaner. After 50 on the throttle position I'm not sure if the whistle goes away or you just can't here it anymore. Inj. We are using Target AFR of 9.0: 1, Fuel Base approximately 40% higher. I was shocked to see it at 95lbs!! So, this is what it takes to put a Sniper on a small-block Ford. Hi Chris , greetings from Down Under (AUS) Just a note on the hi fuel pressure issue . Last night I tried setting the IAC and had the same problems after it's warmed up. Others might require 60 RPM. 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. 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. Please let us know how this works out for you! One of the signs of a vehicle with a rough idle is a faulty Idle Air Control (IAC) Motor. I will turn it up some. If you do find you have RFI issues then I've written an . The noise is definitely coming OUT of the throttle body. The noise changes sound with the throttle position. 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. We will definitely be sticking with Holley from here on out for future retro-fits. After speaking with Holley Tech Support and Tech Support from where I purchased the systemthey decided to replace it. I had a customer who struggled to understand that. I guess we can't have everything. I installed a Holley Sniper on my Ford Maverick 302 V8. Even at 0% it's sucking a bunch of air through the IAC port. Unfortunately I did not buy my sniper efi from you. If you have any questions about the car/setup let me know. Add To Cart. But now that Terminator X is available, I highly recommend going that route. Copyright 2017 Cyberspace Automotive Performance, Inc. All Rights Reserved. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. I watched the butterflies start to open at about 35 on TPS. 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. At low levels RF interference will often reset the ECU so quickly that the engine will not stall. Sometimes an engine can produce enough vacuum to pull the secondaries open slightly. So the issue Im having is low idle. If the vendor from whom you bought the system is coming up blank on ideas then don't hesitate to contact Holley's outstanding tech support department directly at 866-464-6553. If you can track specific engine coolant temperatures where the engine stumbles and dies that would be a good place to start. I've read that a spacer with 4 individual holes will solve this, but after I installed the progressive linkage the noise went away!! The 5-6 times it has happened now have been after the car has been running for at least 20 minutes. ?I never had my Carb Cold start RPM any higher then 1600 RPM.THANK YOU. Even at 0% it's sucking a bunch of air through the IAC port. I have changed my roc/tps to 7 from 15 but that only took me out of learn mode. 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. After it starts it idles around my 960rpm setting + or - 100rpm. That is the only way to fly. Then Friday night as I was driving home, the car started acting up. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. The small rubber plug had a leak. 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. 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. After a stall the car will restart but will be in a high idle. We do that but most places don't. Several good bits here. Keep in mind that at 60 miles the One additional wrap on the secondary coiled shaft spring is all that's necessary. They tell you to ask call Holley. After doing TPS reset it starts fine but when you give it some gas it hangs at 1500 and will not return to idle. I'm wonder if the iac can cause this. Seems like its too slow to grab idle when ac kicks on. We offer some tips to help with that. Genuine Walbro fuel pumps are virtually bullet-proof. Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. The AFR was pretty consistent around 13. 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. no timing control. If you go the other way then you might find that the IAC zero's out when the fans are off. It could be, but that seems unlikely.Instead, you need to look at the basics. The Sniper resets the TPS to 0% each time that you key the system on. It is good to at least know that the Sniper fuel pressure regulator can have high pressure failure issues (contrary to what I posted to Scott back on April 13th!) Make sure that your blanking level is _below_ that (being careful not to find yourself in the situation I describe above.) 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. As you have noted, each time the idle goes up. It is made by one of the biggest names in fuel filters and sold under the Parts Master label so it is quality and great price in one. But I am having troubles.When stepping on the accelerator slightly with idling, it will be 2000 RPM all the time. However, I can't think of a single one that was because of low vacuum. Is there away to program the ecu to compensate for this at start up. 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 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. I'd say make sure you buy from someone who can give you good after-purchase help (hint!) Every time though I can turn the car off and restart and it settles at 850 with IAC 2-4.The thing that has me puzzled is how the with the only difference in condition of the car being the restart, the idle is "fixed"Any clues on where to look next please let me know. Observing the temperature on the 3.5-inch handheld (only), wait for the temperature to achieve 160 degrees F. Once above 160 degrees, turn the idle speed screw so that the idle is about 50 RPM below your target idle speed set in step 1, above. Second, Holley just released over the weekend a video on how to implement a flex fuel sensor on their HP and Dominator ECU's. One way is to very carefully watch the handheld monitor, and that may be adequate. If not then I think you are going to find that this will solve much of your problem. engine works beautiful, the car runs a lot, but suddenly, the engine does that. :-). Overview. Hey Chris That's a nice change of pace--a low idle issue! So I have been doing the slow take offs and thinking that it would learn its way out. Since the shield was put on, not a single problem, not one. Any help would b great. Installed sniper on 65 galaxie. When I cover it with my hands, it gets quieter. It shuts off when coming to a stop sign, at any cruising speed and romdomly at idle in park but never when excelerating. 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 But I still get the iac at 0 and the rpm at 1200. When you first posted this I had no idea how to respond. Holley have given a new unit. Bottom line ismy first one must have been faulty. Try it! In this short video you learn to replace the IAC. The first thing I'd do is check your fuel pressure with a gauge like this. !I called Holley today, and before I could even described the symptoms the This will go a long way to improving your fuel map without manually adjusting the acceleration enrichment. Next, reach down into the secondaries and push the butterflies closed. It only comes back to normal if I turn the engine off and on again. Not good.There isn't set solution here that works for all engines. If there is an issue with using the Sniper EFI TPS signal, is there a remote TPS or an adaptor for the Sniper EFI that allows the TPS signal to be accessed for the transmission. For the first couple of drives it was running well, Sniper EFI was working exactly as advertised. )If you rule out a fuel supply issue then we're going to have to gather a few more clues. Yes it is controlling the timing and I had issues at first and it controlled the idle just fine. My car will now start when its cold, but after about 30 seconds the idle drops down and begins to run like crap. 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. If you remove the air cleaner entirely and the whistle continues then you can rule that out. I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. As always, I recommend great restraint in changing any of the parameters until a significant amount of learning has taken place. Intermittent stalling usually points to radio frequency or electro-magnetic intereference (RFI/EMI). There is no real mystery here. You will need to change the -40 degree idle speed setting again but I recommend not touching anything else. 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. 2. 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? But you've got to find where air is getting into your engine.The reason it's going up as high as 2400 RPM is because once you press the throttle beyond 1% the IAC opens to the park position. hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I Simply use your handheld controller and go to the Tuning > Advanced > Advanced Idle > Idle Speed screen and click on the Idle Speed Curve function. Drop the IAC parked position a bit at each temperature point and sort of back into the solution. it seems to ramp to 60 psi on the initial prime, but as soon as the motor start the psi spikes.I guess a workaround would be an inline return/filter regulator? Key, I believe, in this success is solid connections, resistance-free signal and ground paths, and solid RFI rejection. The engine makes very low vacuum at idle. 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. Definitely would have went with you guys. Cl. Sorry for all the questions, new to the efi world. You could go either way.. In the wizard I set my Idle to 500RPM but it never got slower than 800RPM, if I run the wizard again and lower to 400 RPM then it never gets lower than 700RPM.After reading about the Idle Speed curver I checked its settings and found that the curve was 300rpm faster at every point over the temp range no matter what temp I had, I adjusted the curve to match what I put in on the wizard and now the RPM is correct, I'd say you have a bug in the wizard.Idle Speed > Idle Speed Curve: Here is where the lack of coolant temperature is going to affect you. It is probably that your RPM above the maximum point at which ramp-down can occur. I went on the good ole interweb and found your website which was VERY helpful! such high fuel pressure. I received from the controller manufacturer greatly understates (at best) the repeated failures of others I know personally who have tried and failed. 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. Consider adding fuel in the AE vs TPS and/or AE vs MAP ROC tables in the area where the stumble is occuring.Since this is happening at such low TPS levels it is possible that your engine would prefer a lower (richer) target AFR number at idle. I'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. *Possible delays due to Covid-19 click for more information. If you find that adding 5-10 degrees of advance helps then it's time to do reconfirm TDC. 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). I have turned ignition off turned screw in 2 turns and turned ignition back on and tps is at 1-2% not sure whats going on. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. Once you know that then you can work on those problems. It sounds a little different from mine, since it commands a 1300 or so increase intermittently. I did change the -40 thing also. Did you find this enlightening? 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. I then saw you guys have an awesome little gauge that can hookup inline to the snipers existing fuel feed?? And your understanding of how the throttle position affects idle is exactly correct. Thanks, That is an strange situation. I'm running a 408 sbc. I never had a problem with this. Let's start by not assuming anything. Jump on board now! 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. 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. P.S. 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. back upthe RPMs shoot up to anywhere between 1500 and 2000 and they will not get You can find those settings here: Handheld: Tuning > Advanced > Advanced Idle > Rampdown, Software: Idle > IAC Settings > IAC Ramp Down. There is no sense proceeding until your TPS is at zero at key-on. If you use your handheld to go here: It is a common one. To do this, open up the Initial Startup gauge screen that was used in section 17.0. It's all part of the pleasure of EFI. I appreciate the help youve given to everyone as it continually helps me! There is a chance that the IAC is open but displaying 0% so start by putting your finger over the IAC opening. They are prone to be inaccurate. 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. That is certainly not normal! First, recognize that the IAC and the TPS are not inter-related in any way. 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. The fuel pressure regulator in the Sniper is fairly simple and not prone to failure, as far as I know. If the engine idles at 750 RPM with the throttle plates all the way closed and the IAC at zero then there is some sort of an issue. About two minutes after I get it set at 850 & 5%, it has progressed to 100%. Rpm with 4-8 iac but it still shows red and shuts off randomly at idle and it won't even drive 2 miles without shutting off. Or ?I have put a fuel pressure gauge right at the inlet of the sniper and it is reading 60-64 psi. The problem I believe this is creating is after I start vehicle (and its still in park), the IAC drops down to my hold percentage of 10% (since throttle % is not 0) before engine is warm and therefore causing the engine to stall out. This increased idle speed is triggered by grounding the orange wire in the 10-pin I/O harness. Give that a go and see if you don't make some progress! Also its extremely rich at idle. At some point you come upon problems that evade the easy answers and this is a good example. The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. When stopping, the brakes are unable to overcome the engine so I go to neutral just to stop fighting the engine. Even though the Sniper's fuel map is programmed to provide the correct amount of fuel via injectors spraying at 60 PSI, if the pressure is jacked up to 90 PSI the wideband sees that you are rich and faster than you can even detect it audibly lowers the duty cycle to inject the correct amount of fuel. Just wondered if you've ever run across a system not powering up? New install, when in setup wizard TPS says 90 percent and I checked the linkage and butterflies. Please check your process again and see if you can see very specifically what is not working correctly. The fuel pump is mounted under rocker panel as low as possible and far away from any heat. Worst case you'll have a spare on hand, and if the TPS is faulty you will have solved the mystery. 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. So I had my Idle set up perfect, with idle timing control off and engine hot the IAC was right at 2-4%. It's called tuning. I think that this time around you will find that it starts and idles really well and only gets better from there. My Sniper started having a ticking noise-- I have 90 miles on my Sniper, but this started the last 10 miles or so: it still drives fine, but it worries me so i've stopped driving it for now. Interesting question. The first place my eyes go when there is any issue with the idle is to the TPS value. I'm so glad you found this helpful--that makes my day!Don't get too concerned about the specific learn percentage. There's a procedure there I can share with you if you'd like.. Not to bandstand here but this is the point when where you bought your system is so important. It turns out that some of the Snipers are shipping with the minus 40-degree setting drastically lower, as shown in the following image. I called support line he said he would have to look into it and call back. Please give this a try and let us know how it works! The IAC is hanging open and not really at 0. 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. I was looking at a data log from my truck earlier this week and noted that at idle my IAC was zero. So, clearly, the "No" answer is wrong. I have been able to get it pretty I'd suggest that you assume everything the previous owner did was wrong until you can prove that it was done correctly. 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! All times are GMT-6. Changing the rpm curve and target rpm has no effect. Price Point: $$, EFI Systems based on Holley's world-class Dominator and HP ECU's. Possibly cap, rotor, coil? It is temperature dependent but 30 is commonly where you find it. I set it exactly like the instructions said and my iac is not only all over the place but when I finally did get it to the 2-10 range it's highlighted in red. Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. check, I guess after reading everyone saying how great the system is after It then idles up from 750 to 1100. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? At idle my IAC is 3-4, AFR around 13-14, TPS is 0, timing 15-17. All in all, considering the system has been installed for less than 2 hours drive time we're BLOWN AWAY at how quickly it is "learning" this engine. I am having an issue with the IAC on the Sniper. % = 49 Drives just fine but won't stay running unless I keep my foot on the gas. 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. liverpool tactics fifa 22, is curative a legit company, hansgrohe vs delta,