Keep in mind that at 60 miles the It could be that you've left a vacuum port unplugged, it could be that the throttle plates are misaligned (unlikely), it could be that your IAC is not closing properly. 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. Find a lower price anywhere and we'll beat it by 5%! If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. They are prone to be inaccurate. 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. Hello Chris. 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. Thank you for this guide on setting IAC. Running the vacuum advance and of course I time it disconnected. If idle drops below 800 it wont come back itll chug around 300 rpm for a few seconds then die. If you suspect this then try to find a situation where this occurs where you can safely check the secondary throttle shaft and see if i's slightly open. )Then look a the datalog and find out what TPS ROC and MAP ROC is most likely to cause the problem. Was perfect idle iac reading 3. Hang in there--you can do it. 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. A problem since day 1 - YouTube Leave a comment if you've had this issue and how you resolved. After speaking with Holley Tech Support and Tech Support from where I purchased the systemthey decided to replace it. The Sniper will be controlling the timing so it will be based on a multitude of factors. Hello. 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. 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. That could be a problem with the TPS or it could be some sort of throttle linkage issue. Don't try to correct for the fuel. The last pic is with the car in Drive. That is the first thing you must find. And yes, monitoring the fuel pressure is the right answer. 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. We are running a Sniper on my mates 355ci small block V8 & so far he is very impressed ! I think you will find that it will learn its way through this. Chris, Take it a step at a time. Also, I was seriously rich at idleso rich it hurt your eyes. It wont fire up. Idle Tuning is a very important part of tuning any EFI system, especially our self-learning units like Sniper or Terminator X EFI. Sniper EFI offers superior throttle response and wide-open throttle power. Setup: 1965 Impala SS; ZZ6 Crate Engine, EFI Distributor. I think that this time around you will find that it starts and idles really well and only gets better from there. 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. I am Japanese who attached Sniper EFI. See these. I go into much more detail about that in this article on startup tuning. Fortunately, I have an article that goes into this in some detail. When stopping, the brakes are unable to overcome the engine so I go to neutral just to stop fighting the engine. They always responded to my questions with guidance that helped me choose the right system for me. 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? I looking for your expert opinion. In addition to avoiding this particular problem, the total solution is much better. It could be, but that seems unlikely.Instead, you need to look at the basics. Should the iac% fluctuate? We're never going to fill up your email box with nonsense. The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. 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). Any suggestions? Do I have to hook up sniper ac wire to relay or should iac pick up idle? Clearly, something is changing. Of the two options, I generally recommend the self-learn. Even at 0% it's sucking a bunch of air through the IAC port. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. You can drop it down and you will find it will behave more like you expect. If you haven't installed a The noise changes sound with the throttle position. The IAC should display a 2-8% to bring the idle up to the actual target. Just wondered if you've ever run across a system not powering up? These aren't generic newsletters either but instead personalized emails. Technically it is a warranty-voiding maneuver so proceed at your own risk. Pw. Also what would you say a desired idle should be for a 3 speed automatic ford? engine works beautiful, the car runs a lot, but suddenly, the engine does that. I did read some comments on regulator issues is there a way to check it for an issue ? May God's grace bless you in the Lord Jesus Christ. back to trying to zero down an idle. I will let you know what the results are. As far as the timing light, I don't know, because I was having problems getting it to work, and that's where I stopped. It meets the target idle perfectly in either but if I lightly stab the throttle it tries to stall after slightly revving. If the connection is loose it will cause the system to shut fuel off because the signal telling the EFI the motor is turning stops (to prevent excess fuel from being dumped in the motor). Also its extremely rich at idle. If you complete the process and find that the IAC is less than 2% at idle, repeat the process and use the set screw to make the RPM about 60 RPM below the target. Is that normal? I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. Thank you. Only show this user . Installed sniper on 65 galaxie. 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. 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!) 90% of time with engine hot. Switch power to the Sniper on and crank the engine. Idle when warm was 850-ish and IAC 3-4 just as when I readjusted it the night before. 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. The idle is 1350-1400 with the idle screw at initial contact. Just add 5 or 10 degrees of advance and see if it doesn't idle better. I do know that the reference angle is 57.5, the inductive delay says 100.0. They also recommended that their ground be spliced into the Sniper ground as close to the Sniper as possible. It is how the engineers allow you to clear a flood condition when you detect it. 2. If I block off the iac with tape , I can get it to somewhat idle, but its not consistent. Note that Brazilian gasoline has 27% ethyl alcohol. Give that a go and see if you don't make some progress! 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. Just getting it to act right at startup is a struggle. (Grease can sometimes do the same thing as a more permanent gasket sealer without making the removal of the air cleaner such a pain.). Fortunately, these are much easier to solve. I would only play with this if you are finding that the other adjustments I suggested aren't working. I'm happy to walk you through what is required. If so remove it. Interesting situation you have. https://www.youtube.com/watch?v=2JpHlS1ymBc, If this is your first visit, be sure to And your understanding of how the throttle position affects idle is exactly correct. I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. 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. But I wanted to go ahead and answer this so that it would make sense to someone who might not go that route.I think the first thing I'd do is try another pressure gauge. 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. Shut off the engine, ensure power to the Sniper is switched off. After much diagnosis, I ended up replacing the intake manifold gaskets. But he kept having problems so eventually he did a complete check and then he found the problem. :-). Should I just disable idle timing control? I haven't driven it for the 30-40 minutes like the several times it idled at 2200. I have never seen issue when CTS is below 120 degrees. Turning it off and back on would reset it, and then it would work as advertised for a while. I did change the -40 thing also. Another suggestion is to add an extra turn to the spring built into the linkage to increase the closing force on the throttle shaft. Okay, try my method. Sometimes an engine can produce enough vacuum to pull the secondaries open slightly. 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. Thanks for any info./insight you can provide, Mark. One of the best Ive seen so far. 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. Thanks again. 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. However, I can't think of a single one that was because of low vacuum. You might even want to add our 4-foot extension harness that will allow you to connect/disconnect the display or CAN-to-USB adapter from inside the car (rather than trying to do that leaning over the engine and under the breather. Ensure that the secondary linkage is completely closed (both visually and manually.). Adding a wrap to the return spring on the shaft is one alternative to solving this. I never had a problem with this. You can re-enable this after you have completed this idle speed adjustment process. have noticed on the hand held is that Air/fuel Ratio rises to 20 +/- A/F and the If you do find you have RFI issues then I've written an . The motor has 376hp at flywheel and the car is a stick shift. Idle was back to normal but iac was at 0. 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! Now I have most of the bugs worked out it runs fine on the highway and around town it's just the idle. However, I have never found that to be the case. Then, when you experience the high idle, note if the IAC number has increased. 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. When I shut it off then start it First, recognize that the IAC and the TPS are not inter-related in any way. Are these compatible enough? EFI System Pro had everything I needed for my EFI upgrade. It's not that they (or any other manufacturer) is 100% perfect. The idle will not return to the set value.The second issue is the same as the first but the motor will stall out. 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. So, this is what it takes to put a Sniper on a small-block Ford. If the TPS is 1% or below then the ECU is in control--2% or greater and the ECU thinks you've got it under control. The Sniper even has a feature that allows it to use the idle timing to control the idle speed. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! 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. If you hit the gas it pops & backfires through the throttle body. 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. Good luck! !I called Holley today, and before I could even described the symptoms the Even then, recognize that over time the IAC will need to be readjusted to compensate for minor changes that will cause it to drift. I hope everyone enjoys this v. Really appreciate the amount of learning im getting off here. 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. $107.95. They tell you to ask call Holley. I have seen this become blocked with debris / dirt in the fuel system and cause a high fuel pressure condition . The manifold pressure increases with the throttle opening but the RPMs are still low. I'm wonder if the iac can cause this. Please advise. It appears that I could now use the dongle and a laptop to custom tune for idle issues if needed. I have certainly seen this before on other fuel injected vehicles when hot. This is extremely unreliable afrer warm. We've already tried adjusting the Acceleration Enrichment chart in all ways, going up and down, RoC Blanking, everything, it has no effect. To figure this out it's going to be important to gather a bit more data. Is there away to lean the idle out? I'd recommend you contact Holley Tech support to get their input (1-866-464-6553; call early for the shortest wait times.) Doesn't want to start, runs like crap. After it starts it idles around my 960rpm setting + or - 100rpm. 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. A few, however, get tangled up getting the idle control working just the way they want. But before you adjust the ECU to lean the idle out, first confirm that your fuel pressure is right. I have not heard of this. The engine makes very low vacuum at idle. Hi Chris. Those little 1/8 NPT gauges are pretty inexpensive and generally pretty easy to find locally.If you confirm that the pressure is indeed 90 PSI you could pull the fuel pressure regulator apart and check it. After pumping the pedal a few times at different times it dropped to zero and started to work. First, check to make sure that the IAC is properly mounted and connected. Chris's Idle Speed Adjustment Instructions*: *Note: If you are using your Sniper to control ignition timing then I recommend that before you start this process you disable idle spark control If you are trying to do this while the ECU is simultaneously trying to bring your idle under control by adjusting the advance it is going to be counter-productive. 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. 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. Either the Walbro pumps you are getting are not genuine (lots of forgeries being sold) or else you have something that is killing them. I am having an issue with the IAC on the Sniper. To finish, I rather tightly twisted the TPS signal and ground wires all the way from the controller to the Sniper TPS and very carefully routed them away from sources of RFI. Thanks for all your help Chris! You just need to go back through the IAC adjustment procedure now that idle timing control is enabled. Car has run perfect every time and has never hesitated or stalled since. 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. Its just at low speeds, not sure if its loading up or leaning out. I set the AFR at 13.5 and all is good now. Maybe Holley will add Fuel Prime Multiplier to Terminator X later. If it is then something is commanding the ECU to open the IAC. Glad to hear that things are working well! That is likely just confusing the issue.Instead, choose whichever setup most resembles your camshaft and stick with that. This will let you know at a glance if something is going awry with the fuel pump. After this whole process, the car normally rotates without a very abrupt pedal. Yes, it will talk to you--but not with words. Though it started and ran good, it was dumping fuel and would not lean out to AFR set points. While adjusting the screw if the TPS position reads begins to read higher than 0% cycling the ignition switch will recalibrate the TPS back to zero. So I had my Idle set up perfect, with idle timing control off and engine hot the IAC was right at 2-4%. Common killers: No filter in front of the pump, reverse wiring, driving with PWM voltage, running at dead-head pressure.Since it sounds like your pressure is right, and since the Holley system doesn't provide a PWM voltage, that pretty much rules out everything but the lack of a filter. From herethe cycle continues and I am I have an adapter on the manifold for squarebore to spreadbore and then a phenolic spacer. Holley Sniper Iac Delete Everything was working perfectly and I shut off the engine. It starts cold fine, its just when its hot. Properly configured, the Sniper does a fantastic job of responding to the transition from Park to Drive. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. I ask because I'm using a PCV valve with my Sniper and have random idle issues as well. The "Gauge Text" is what would be shown on a 2-1/16 gauge or the Avenger handheld display. To keep it running in gear, I have to bump the neutral idle up just over 1000 RPM. )Since this isn't a consistent issue with all Snipers that tells me that different IAC settings tend to make the whistle. to. Thank you very much. This curve runs fom -40 degrees to 260 degrees, and gradually reduces the RPM along that range. Except at idle. That's what you're seeing. Cycle the ignition as instructed by the handheld and then navigate to the distributor setup screen. You may have to register before you can post: click the register link above to proceed. Then a little faster--until bogs at that level work themselves out. So you installed your Holley Sniper. Hi Chris , greetings from Down Under (AUS) Just a note on the hi fuel pressure issue . 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. I think that the more important point is that Holley kept sending him units until everything was working. The second thing to realize is that even after you get it just right, you need to keep an eye on the IAC number and reset the idle if it gets outside the 2-8% range when idling when warm. (I'm running from a fuel cell on the garage floor 10 feet away with lines in plain sight and do see fuel coming from the return at a decent flow. 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. 34K views 1 year ago Holley Sniper How to Set The IAC Idle air Control in 5 minutes or less. All times are GMT-6. The warmer the motor, the higher the idle will be at this point. 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. In the time it takes to add your email address you can be at the top of the heap for getting the latest information from our authority. Could be a bad IAC motor, replace it and see if that solves the problem. 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 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. ?I never had my Carb Cold start RPM any higher then 1600 RPM.THANK YOU. Use the idle speed screw to set the idle at a comfortable warm-up speed. What can I do? I can have it working fine (5% to 10% at target idle at operating temp.) RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the Also ensure the TPS Position returns to zero at idle, & the IAC Hold Position isn't setup too high. Then your low idle problem will go away. First--besides the fact that it's not represented on the display, it is not even a parameter that you can datalog. In the datalog the engine is running at 1400 RPM, TPS is zero, IAC is zero, CTS is 185F but it's in Open Loop. I straightened that out, got it running and that's where it goes downhill. Price Point: $$$. If you remove the air cleaner entirely and the whistle continues then you can rule that out. Idle quality is great, RPM is good, sometimes IAC is jumping around from 35 to 60. With select intake manifolds, the distributor housing and IAC valve on the back of the Sniper EFI throttle body are fighting for the same . In the Wizard, select the stock cam setting. It turns out that some of the Snipers are shipping with the minus 40-degree setting drastically lower, as shown in the following image. After 50 on the throttle position I'm not sure if the whistle goes away or you just can't here it anymore. If you haven't confirmed that they it is worth checking. It started right up and we did your idle control fix and all is good at idle. If you patiently adjust this over the course of days you will get it just right.Again, glad this is working for you and look forward to a good report in the future! :-)Yes, learn impacts idle too, and remember the even when the basic learning is done there will continue to be some learning for changes in weather, altitude, etc.Go ahead and try a few idle settings and see how they impact the idle-speed searching. This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. It then idles up from 750 to 1100. = 2.34 For someone in your position, it will become an indispensable tool in your tool box. Earl's Mechanical Fuel Pressure GaugeI could use that for a quick troubleshooting for 1/3rd the cost of the Holley one. Hello Chris. you have it set. At this time, TPS is 0%, IAC is 50 to 60%. If the TPS reading on your Sniper EFI System does not reset to zero that is a problem that needs to be addressed. Hello Chris. While confirming, in the handheld ensure that the Reference Angle is set to 57.5 and that the Inductive Delay is set to 100. So, clearly, the "No" answer is wrong. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? Wish I had bought my sniper from you, but unfortunately didnt. I have tried your 10-step idle adjust and ive adjusted the idle curve. 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. Start with the most gradual throttle input you need to launch well, then slightly increase until you feel some stumble. Relatively new Sniper EFI install on a '69 Mustang 302. 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. What I can't explain is why your TPS is acting so randomly. Hey Chris! After a stall the car will restart but will be in a high idle. Cycled the ignition off. Covered the IAC port and set idle for 850 ish. What must remain foremost in your mind is that the only thing that can cause the idle to increase is additional air getting into the engine. If not then you have some other issue that is behind this increased idle. Both answers you've received greatly oversimplify the truth in favor of the answerer. If you feel you have no other choice but to run a Sniper and stand-alone controller then you can give this a try. Seems to be working. This is normally used as an A/C idle-up circuit. I have one customer who is having some similar issues and his AFR is down at 9.6:1 when it won't start. You mentioned going from 13.5 to 14.2 but you'd want to go in the other direction--maybe to 13.2. Bolt-on carburetor style EFI for your classic car or truck. It could be a couple of things. We'll also be contacting you for future purchases now that I've discovered you! Often, folks will say, "I did everything you said. port that goes right on the inlet of your Sniper and makes installation a breeze.If your fuel pressure is solid at about 60 PSI then you should start looking at I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. If not then I think you are going to find that this will solve much of your problem. Its rare that you find someone that genuinely wants to help and see something work good, the information I have received from this page and Chris himself is top notch.1969 Dart GT 340 with a Holley Sniper, I purchased the Holley sniper from jegs wish I knew you sold them put on my truck got the IAC set haven't checked the -40 idle setting yet my problem is my headers are glowing red called Holley I think I got the worst person seemed to care less Afr is set at 12.8 for idle only thing I have changed I don't smell any fumes at idle someone said I could change the coolant temp enrichment but I don't know if it is rich or lean I figured since no smell it is lean any ideas would be appreciated thanks i have a fuel psi gauge reads 60 psi don't wanna melt my motor did not glow with a carburetor. When I finished the install on my C10, I set it as follows: 13.1 at idle, 14.2 at cruise, and 12.9 at WOT. I am having an idle issue (other than that is absolutely perfect). your IAC is at zero. Suddenly, the engine accelerates alone, hears a great deal of air being sucked in, I installed the Sniper on my 1978 Ford F-100 with a small block ps. I called support line he said he would have to look into it and call back. That 60% (which is configurable) is known as the Clear Flood TPS. You'll have to go back and forth a couple of times to get it just right. 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. The tps has slotted holes, can you adjust it to get to zero? Sorta similar to a carb having the idle mixture set incorrectly (rich) or the idle speed too low. Engine warms up to 195 degrees and stays. Super helpful and knowledgeable. Does that make sense to you? I'm Having trouble with the Sniper on high Idle. 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. So check that timing and I think that you're going to find you need a good bit of advance.