holley sniper efi iac problems

I have never seen issue when CTS is below 120 degrees. Hello Chris. There's a procedure there I can share with you if you'd like.. I would suggest you take a look at that if you haven't already. Check the Distributor Tach Connection to the EFI. 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. Then it changes and will not idle down, the handheld will display 0% IAC but you can see and feel that the IAC valve is more like 100%. 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. Have a look--I think this is going to allow you to fix your idle problem. You want to ensure that nothing is hung up in there.The only thing that I can think of that would cause the fuel pressure to spike when the motor starts is the increased fuel flow at the higher alternator voltage (jumping from 12.0 to 13.5 volts or so.) This was an issue in the earliest version of the Sniper firmware. The weather in Ct has finally improved and I have put about 60 miles on the car with the Sniper system. The data that you provide shows that you have at least two problems. If I cruise down the road at lets say 60 mph and lay into it, she will take off and go. close to idle with the IAC between 2% & 12%. Yes, it will talk to you--but not with words. It is a common one. Always had to set idle above 950. I have driven it a few times maybe 100 miles or so. Fought a high idle issue until I changed your idle speed curve fix along with dropping the IAC hold to 10%. When you key on, you will hear three distinct sounds: The ECU initializing the IAC, the fuel pump priming, and the injectors firing their prime shot. The "PC Text" indicates what will be shown on the PC/Laptop data monitor or data logger. The only way to confirm RFI problems is by doing a data log. No big deal, just time to re-adjust! If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. What might cause the TPS to go to 2%? Do you have any clue? The broad consensus has been that the Sniper is an amazingly straight-forward install and starts and tunes as expected. Then follow all of the instructions above, including confirming the idle speed curve setting at -40 degress as well as following my 10-step process for setting the idle. 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. The timing can drift 0-30 degrees just due to the width of the rotor tip. You have to remove all hoses in order to debug the problem. If it does then you can put on a heavier spring so the advance doesn't come in as fast, or use a lighter weight. 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. Hot start it most of the time wont start unless I give it a little throttle. That will happen occasionally, but less as time goes and on and the engine tune stabilizes. 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. Ok, so there are a couple peculiar things going on here. Relatively new Sniper EFI install on a '69 Mustang 302. EFI System Pro had everything I needed for my EFI upgrade. Now I have most of the bugs worked out it runs fine on the highway and around town it's just the idle. Ilike a few othersam having idle issues. 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. MAP Sensor. I have driven car about 200 miles. The last pic is with the car in Drive. Yes, let me know how that setup process works. I went on the good ole interweb and found your website which was VERY helpful! Sometimes an engine can produce enough vacuum to pull the secondaries open slightly. 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 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. Jump on board now! And your question is very perceptive: You must first know whether the bog is a lean or a rich condition before you can make the correct adjustments. Thanks Again for your help. Interesting question. That is a good thing.I don't have a specific target RPM but always encourage automatic transmission users to bias the idle just a tiny bit higher than what you might otherwise. Could you provide me with some things to check or some things to adjust? Contact whomever sold you your system or Holley directly. Hi Chris , greetings from Down Under (AUS) Just a note on the hi fuel pressure issue . Price Point: $$$. )Then look a the datalog and find out what TPS ROC and MAP ROC is most likely to cause the problem. Next, reach down into the secondaries and push the butterflies closed. You'll have to go back and forth a couple of times to get it just right. 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. Thank you for your input. 2. Given the circumstances I would say that it is either the IAC motor itself or RFI but you seem to have ruled both of those out. You've got it running and warmed up but now you need to set. Well, it turns out that with the current firmware this throws the IAC control into a bit of confusion. 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. All EFI systems need a large fuel filter to trap dirt and yet not reduce volume. It then started working normally again. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. Honestly, I've never seen this happen but if the butterflies were misaligned on the shafts it could allow too much air to enter. Some advanced conceptsIf you have the Sniper Can-Bus to USB Adapter, you can connect your laptop, open the software to the learn table, and get a visual for where in the table you are experiencing the lean bog. 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. That is certainly not normal! This is actually more troubling than the sound you originally described. And, while that is happening, make a note of the temperature before you engage the starter, and then the rpm when it starts.The Idle Parked Position is set on a temperature-based graph like the Idle Speed Curve. Even though you think your timing is perfect I'd suggest you try cranking about 5-10 degrees of advance into the distributor and just see if that doesn't work better for you.Remember this: adjustable timing pointers go out of adjustment and harmonic balancers slip. Get that thing installed and you're going to know a whole lot more about what's going on. 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. As inconvenient as it might seem, I'd recommend keeping a timing light handy and checking your timing during the high idle condition and then again after restarting. Adding a wrap to the return spring on the shaft is one alternative to solving this. Idle Tuning is a very important part of tuning any EFI system, especially our self-learning units like Sniper or Terminator X EFI. I've helped folks work through a number of challenges with their Sniper EFI System installations. :-). Engine has never stalled with Sniper system, once placed in Drive it just goes!!! TP range is normal goes up to about 90% with throttle pedal to the floor. I would only play with this if you are finding that the other adjustments I suggested aren't working. $107.95. Note too that the larger the throttle stab, the more brief the time in that cell and the more gradual the change.Here's what I recommend: Get somewhere where you can repeatedly stop and go. is train the system or there is actually something wrong.I do love the system at any ideas? If I put the truck in neutral the TPMS will raise all the way up over 2000. I would continue checking the electrical connections along the fuel supply. One of the signs of a vehicle with a rough idle is a faulty Idle Air Control (IAC) Motor. Sorry I didn't buy from you but I didn't know you had sold them. I figured out I was going the wrong direction when I was messing with the AFR programming. and go to restart warm, it catches starts for a flick of a second, drops to a stall, or sometimes will catch its self and start. The IAC reads 36 when at idle fully warmed up. If you have somehow overlooked this, start here: Holley Idle Speed Adjustment Instructions: Once the engine is up to operating temperature, the idle speed can be set to what was configured in the Wizard. nothing stays steady. Then do it just a bit faster--just enough for it to bog a bit. This curve runs fom -40 degrees to 260 degrees, and gradually reduces the RPM along that range. The fact that it ran so (at times) with 90+ PSI fuel pressure is a testimony to the Holley's closed-loop technology. 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. Running a bbc with coil - my timing is perfect. Do you have a PCV on the engine? My car will not idle right until it gets to around 130 -140 degrees. The 5-6 times it has happened now have been after the car has been running for at least 20 minutes. First, let me congratulate you on your patience in letting the system learn. If not then you have some other issue that is behind this increased idle. 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. It meets the target idle perfectly in either but if I lightly stab the throttle it tries to stall after slightly revving. I also raised idle at Park a bit with the idle screw. when things aren't working and this provides just that. Thank you very much. I.e. After only running for about 15 minutes or so the system starts to fail stalling the motor. (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. At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. 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. If you find that the IAC is more than 8 percent, repeat this process and instead of shooting for 50 RPM below your target make it only 40 RPM below the target idle speed. Throttle Tip-In puts you in a part of the fuel map where you stay for only milliseconds at a time. 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. Copyright 2022 Holley Performance Products, Inc. All right reserved. Wish I had bought my sniper from you, but unfortunately didnt. Should the iac% fluctuate? 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. Target AFR, A / F = 13.5 He has walked me through every question Iv. I've been messing around for a bit trying to eliminate any possible vacuum leaks. Is this normal ? I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. Ensure all your sensors are displaying proper values. As always, I recommend great restraint in changing any of the parameters until a significant amount of learning has taken place. To be honest, you sound like an ideal candidate for Sniper ECU ignition timing control. Check fuel pressure too (. My dad wanted to recheck the timing so I set the Static Timing at 15 and it runs perfect. Then Friday night as I was driving home, the car started acting up. Advanced throttle body injection systems capable of transmission control and more. I am new to the EFI scene but want to learn. Idle was back to normal but iac was at 0. There are a few tell-tale signs that can help you diagnose the problem. 30 minutes later CTS reads 161, start engine Idle is jumping from 450 (almost stall) to 1500, IAC is jumping all over 10 90. What is it supppse to be at idle and while driving under heavy acceleration? The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. I'd say make sure you buy from someone who can give you good after-purchase help (hint!) First, check to make sure that the IAC is properly mounted and connected. 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'm wonder if the iac can cause this. Have you confirmed your fuel pressure at idle is 60 PSI? 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 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. Featured Products Sniper EFI $7.07 - $2,457.95 470 Products View Parts author Staff Writer 1711 Posts An Article About Video tech Sniper EFI Videos Sniper EFI Tech Sniper EFI sniper Installation Copyright 2022 Holley Performance Products, Inc. All right reserved. Ive played with the timing on this thing multiple times.Car was fullly restored last year. (It should be at or near 60 PSI at idle. A problem since day 1 - YouTube Leave a comment if you've had this issue and how you resolved. Yes it is controlling the timing and I had issues at first and it controlled the idle just fine. 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. it will jerk and rpm will go up and down and AFR will be around 20 : 1 or more or less. Ok, so I'm stumped! But after sitting static idling for a little bit, the IAC goes to 100% & stays there. Any ideas here? These aren't generic newsletters either but instead personalized emails. I did change the -40 thing also. You can drop it down and you will find it will behave more like you expect. Hey Chris! 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. I've read that a spacer with 4 individual holes will solve this, but after I installed the progressive linkage the noise went away!! 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. Maybe Holley will add Fuel Prime Multiplier to Terminator X later. I received from the controller manufacturer greatly understates (at best) the repeated failures of others I know personally who have tried and failed. It is always best to get the base map as close as possible before adding acceleration enrichment. Any idea's? Drop the IAC parked position a bit at each temperature point and sort of back into the solution. If you remove the air cleaner entirely and the whistle continues then you can rule that out. Also ensure the TPS Position returns to zero at idle, & the IAC Hold Position isn't setup too high. 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 In the setup, I set the hot idle for 850. I think I figured some of my problems outI'll try to explain. So, clearly, the "No" answer is wrong. 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. 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. Intermittent stalling usually points to radio frequency or electro-magnetic intereference (RFI/EMI). We have shipped quite a few of these to customers in Australia and New Zealand so I know that there is becoming a good following there!We recommend this Inline 10-micron fuel filter to prevent problems like that. Be sure to re-enable it once you get your idle tuned. In the warm state IAC adjusted to a position of 2 to 10%. 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. Just add 5 or 10 degrees of advance and see if it doesn't idle better. I had a customer who struggled to understand that. If you have performed the adjustments above and still have RPM issues, it's time to look for clues. check, I guess after reading everyone saying how great the system is after I installed the Sniper on my 1978 Ford F-100 with a small block However, whenever you start changing things, you can get into a chain reaction. I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. With everything else being right and since you can make it start by adding fuel it seems like you must have some sort of fuel pressure issue. I recently bought the car with the EFI system on it. Data logs show no EMI/RFI. Cycling the power to the Sniper EFI would cure the problem, but not prevent it from coming back. I straightened that out, got it running and that's where it goes downhill. I installed the Holley Sniper in my Chevelle this winter with a brand new BluePrint 496. If the TPS is even just 2%, the IAC will go to the hold position (normally 30%) and will not change until the TPS goes back below 2%.If you create a datalog you will be better able to confirm if something is not working correctly. Is this an issue to worry about? Holley will take a look and tell you you have RFI and wish you good luck in finding it. This minimizes installation time and packages really well on a diverse group of engine applications. When you open your IAC to 30% you are naturally going to have a high idle condition. Earl's Mechanical Fuel Pressure GaugeI could use that for a quick troubleshooting for 1/3rd the cost of the Holley one. A good example of why it's so important to run a good pre filter in the fuel line. I recommend confirming there is no throttle linkage issue first. It may take a few tries. Start engine let it warm up to 160, learn mode is learning. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. Then, the next time I cranked it, the idle went high and won't come down!" I have a set of 8.8 Accel Rfi suppression wires on it. Were the additional load a simple step function it would be challenge enough for the ECU to gracefully increase the engine speed without overshooting. Chris---I am contemplating replacing my Holley 750 on my new low vacuum 600 HP 496 with the Holley Sniper FI system. You could go either way.. 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. Once you know that then you can work on those problems. First thing I would check Cl. Part# 538-13. Sometimes it sounds like it wants to crank at the start but runs out of gas. If it creates an issue (not normally the case) then you'll know. I hold my foot steady in place it does this in 5 second cycles and if i let go of Add To Cart. Otherwise, if removing the air cleaner eliminates the whistle then try to use a thicker gasket or try lightly greasing the gasket. The throttle plates are misaligned. :-). These problems will go away when you do that. Even at 0% it's sucking a bunch of air through the IAC port. 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. Just thought I'd ask as there isn't a lot of info out there. Should it not do the opposite and do this on a cold start not warm. I have a 406SBC that does most everything right with this sniper setup. What should I be looking at to calm this down? If you do find you have RFI issues then I've written an . Chris I am having a little different idle problem I did your -40 thing and that help with high idle but my problem is it idles fine until I drop it in gear and it stumbles a couple times catches up and then idles fine again. I'm happy to walk you through what is required. Usually it wont stay on 0% very long and soon changes to another number like 1 or 2%. No matter what do, my idle will not drop below 1350-1400 RPM when the engine warms. That is the only way to fly. When you set the Static Timing to 15, what did you read with the timing light? Thanks for any info./insight you can provide, Mark. And your understanding of how the throttle position affects idle is exactly correct. First--besides the fact that it's not represented on the display, it is not even a parameter that you can datalog. Worst case you'll have a spare on hand, and if the TPS is faulty you will have solved the mystery. New install, when in setup wizard TPS says 90 percent and I checked the linkage and butterflies. 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. I then saw you guys have an awesome little gauge that can hookup inline to the snipers existing fuel feed?? Edit I just ordered a Holley return / regulator and cap for the sniper ouletOh, this is not an OEM Master Kit, but the fuel pump should be the same EFI Pro shipped this kit. Switch power to the Sniper on and crank the engine. carburetor setup, but it does blow when I can't jump on the highway like I use That will at least tell you something. Can the return line be an issue?I have had 2 faulty gpa-4 255 walbro pumps go bad. Between the kick down and the return springs on the throttle body the pedal is so hard to push it's pretty much a jack rabbit start every time from stop, it's almost undrivable, any suggestions on what I could do?thanks for help, I've tried both Holley's tech lines for close to 2 hours with no answer! have noticed on the hand held is that Air/fuel Ratio rises to 20 +/- A/F and the I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. Ran 2 Holley carbs and an Edelbrock. Very annoying ended up being simple my rear plates would stay open constantly it was driving me nuts I'd let off the pedal idle at 1300 blip the throttle a few times finally come back to 850. Your AFR is pegged lean. But as you see from the recent revision I did above you seem to be having a fixable issue. I readjusted my IAC, now it's perfect. https://www.gmperformancemotor.com/parts/19210007.html, http://forums.holley.com/showthread.3128#post83128, If this is your first visit, be sure to 34K views 1 year ago Holley Sniper How to Set The IAC Idle air Control in 5 minutes or less. I am Japanese who attached Sniper EFI. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds When you first posted this I had no idea how to respond. Capability Range: Professional :-). I've not heard of any others with this exact issue so I don't think it is a common problem. 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. If you use your handheld to go here: Hi Chris I didn't get any traction on Holley.com If the minus 40 degree setting is lower than the setting to the right, simply move it up so that it looks something like this: The folks who have tried this have found that their idle speed control behaves much more as they expect. Should i adjust idle screw with the fans already on? This is a mighty big subject for a blog post reply, I should probably start doing some videos on this. The Fuel Base map is perfect, the car works well, runs well, running through the streets, the car is great. Initial Baseline Idle Speed Screw Setting, http://forums.holley.com/showthread.neral-IAC-Info, http://documents.holley.com/199r11031r.pdf, https://forums.holley.com/showthread-Idle-Solution, If this is your first visit, be sure to If the IAC number is increased during this high idle, review the points about high idle from tuning issues. If no air is passing (and the idle doesn't drop) then your IAC is working. 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. So this is my issue ( I did just email Holly). That, on top of your air leak, is allowing the engine to idle at 2400 RPM. Several good bits here. Purists will sniff that these are not accurate to the tenth of a PSI. Now it's at 5% on a big cam 440 Mopar. It's a Chevy 350 bored .030" over it has a cam in it what I was told is the cam has the firing order swapped. After pumping the pedal a few times at different times it dropped to zero and started to work. I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. If you go too high then the motor will not return to your target idle when you come off the throttle. It has a lightweight centrifugal spring kit installed so I reach total timing around 2500 rpm. Chris, I recently installed my Sniper and have an intermittent idle problem. to. I have one customer who is having some similar issues and his AFR is down at 9.6:1 when it won't start. All of the wiring exits below the rear fuel injector cover, for a completely stealth installation. It's pretty hard to get the header tubes glowing at idle with a lean AFR. Don't know if I should put this in a separate post. I never had a problem with this. If The throttle blade adjustment is at 2-6% at hot idle, and with warm engine 185F. I keep doing that with the same result. Was perfect idle iac reading 3. I had this same exact issue. I recently had IAC issues identical to what you describe. 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.

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