holley sniper efi iac problems

If you use your handheld to go here: Intake has been on and off 3 times no change. Make sure that your blanking level is _below_ that (being careful not to find yourself in the situation I describe above.) that my Air/Fuel ration was 15:1 and I believe the target is 13.5:1. Ive played with the timing on this thing multiple times.Car was fullly restored last year. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? Using the handheld, navigate to Tuning > Basic > Basic Idle and ensure your target idle speed is set to the RPM you desire. I have been able to get it pretty That is the only way to fly. But nothing beats a good solid gut-check 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. 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. 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. It will drop down to 400 RPM then climb 500 and then shoot to 900 and then come back sometimes two or three times then catch it self an idle just fine again. 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. Cracked casing from a side cover screw being installed crossed threaded. If you're having issues with your Holley Sniper IAC getting stuck at 20, there are a few things you can try to fix the problem. If I put the vehicle in gear the idle gets higher with temp. If the screen shows iac at 0 and you block the hole to find it open what does that mean? It really takes a lot of throttle tip-ins before you get anywhere near "learned" in this part of the fuel map.Based on your description, it sounds like you have a lean stumble. It sounds like you need a bit more of a fuel squirt on acceleration, Brett. If you go too high then the motor will not return to your target idle when you come off the throttle. 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 Though it started and ran good, it was dumping fuel and would not lean out to AFR set points. 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 10 step set up on your page set my idle perfect and iac perfect a very consitant 700. 400 engine, C6 3 speed automatic, with standard canister coil for ignition, and I have verified that there are no vacuum leaks, not to mention the car runs to good to have a vacuum leak bad enough to make this noise. That is the first thing you must find. I am Japanese who attached Sniper EFI. 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. That is what I really respect about Holley. If there's any run time on your current setup the Sniper may have some bad learn data due to what appears to be timing issues. This question is really outside both the scope of what we try to discuss in the comments section as well as the overall subject of this article. It has a lightweight centrifugal spring kit installed so I reach total timing around 2500 rpm. I have driven car about 200 miles. If you have an installation or start-up issue that is nagging you then please use the comments section to reply and we will gladly provide more information that we hope will be useful to you. If it is then something is commanding the ECU to open the IAC. Fought a high idle issue until I changed your idle speed curve fix along with dropping the IAC hold to 10%. My guess is a faulty IAC since it is intermittent and I have not done any setup changes. (Do this while you are cranking.) Take a drive and stop somewhere for 30 minutes, CTS is 170 when engine was shutoff. It does this with the engine off. Turn the idle speed screw on the primaries in about 2-3 turns after it makes contact with the linkage and starts opening the primary throttle blades. No big deal, just time to re-adjust! Hope this helps! There are a few tell-tale signs that can help you diagnose the problem. it will jerk and rpm will go up and down and AFR will be around 20 : 1 or more or less. You might have a bad IAC, but you can also have a bad vacuum pod on the transmission. That is not a huge problem but it just means the IAC has no ability to lower the idle beyond what it is running at that point. 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. It is reliant on the data acquired by the included wideband oxygen sensor. Do you have a PCV on the engine? A couple of possibilities that come to mind in order of likelihood: Im having an issue with what I think is the Iac. He has walked me through every question Iv. 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. Target AFR at idle is 13.8%. Jump on board now! This is very disappointing as people love to hear the motor while the hood is open.Thanks Jon. While confirming, in the handheld ensure that the Reference Angle is set to 57.5 and that the Inductive Delay is set to 100. Holley will take a look and tell you you have RFI and wish you good luck in finding it. If you see that the ECU is commanding the IAC to 0 but there is air entering the IAC port then it's time to refer to my article on IAC Testing Procedures, Hello,I installed my sniper system on a 65 mustang, with a 302. Even at 0% it's sucking a bunch of air through the IAC port. This is extremely unreliable afrer warm. idle at 1100 on the "stock" file it's better with street strip.The IAC counts will be at zero. )Take a look at your AFR during the starting process. I have adjusted many settings and eventually mess it up and go back to the original map. Drives just fine but won't stay running unless I keep my foot on the gas. The whole topic of using the Sniper TPS for transmission control is one deserving of it's own article but I'll try to summarize a bit here. I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. Enjoy! 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. % = 49 It might be necessary to insulate or re-route your fuel lines if this can't be solved any other way. When I cover it with my hands, it gets quieter. Once you have done this the challenge is to create a datalog that includes the ":snap" you describe. They always responded to my questions with guidance that helped me choose the right system for me. 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. *Possible delays due to Covid-19 click for more information. The IAC going to 30 is normal. It could be, but that seems unlikely.Instead, you need to look at the basics. 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. Don't try to correct for the fuel. Idle Tuning is a very important part of tuning any EFI system, especially our self-learning units like Sniper or Terminator X EFI. At idle my IAC is 3-4, AFR around 13-14, TPS is 0, timing 15-17. I have a set of 8.8 Accel Rfi suppression wires on it. The idle will not return to the set value.The second issue is the same as the first but the motor will stall out. Camshaft is M-6250-B303 .480 lift intake & exhaust, duration at .050 is 224 degrees for intake & exhaust. Thanks in advance for any advice. :-). (It should be at or near 60 PSI at idle. close to idle with the IAC between 2% & 12%. Thanks for any info./insight you can provide, Mark. I put it in neutral and the idle RPM had increased to 2100-2200. See these. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. After manually making the sensor go through the full range a few times, I reinstalled it and now my TP will read anywhere from 0% to 4% when I key on. 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. So glad this was helpful. 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. 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. If you remove the air cleaner entirely and the whistle continues then you can rule that out. It is easily solved by installing a four-hole gasket or four-hole spacer (depending on your hood clearance issues.) What is it supppse to be at idle and while driving under heavy acceleration? I chased that gremlin for about three weeks and was convinced I had a bad throttle cable. Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. I'm Having trouble with the Sniper on high Idle. :-). I set the AFR at 13.5 and all is good now. View Holley Sniper EFI Self-Tuning Kit - Shiny Finish. If your TPS is at zero and your IAC is at some random number above 8% (but not exactly 30%) then for some reason your engine has not met the conditions to ramp down to target idle. At 0% it shouldn't be sucking any air through that port, correct? There is no real mystery here. 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. 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. 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. Car has run perfect every time and has never hesitated or stalled since. I will a, Scott has been very helpful and informative on guiding me through the purchasing and installation of my terminator X max system. Put a strong piece of tape over the IAC breather hole--duct tape or something that couldn't possibly be sucked into the throttle body. 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. Cl. I'll bet you find that you can get it working great without any manual tuning. The data that you provide shows that you have at least two problems. Is this an issue to worry about? Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. If you go too low then it may stumble or even stall when coming off of throttle. 2. And your understanding of how the throttle position affects idle is exactly correct. I have now determined with the TPS the noise correlates with the opening of the secondary butterflies. I also raised idle at Park a bit with the idle screw. Commanding the engine to automatically increase speed when switching into drive is a little scary to me though. 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. Kind of cuts into forum time. Im in Australia, so stuck the sniper on a 355 Holden engine with CD box. It runs perfectly fine other wise. If I put the truck in neutral the TPMS will raise all the way up over 2000. We've already tried adjusting the Acceleration Enrichment chart in all ways, going up and down, RoC Blanking, everything, it has no effect. 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. However, I can't think of a single one that was because of low vacuum. Sorry for all the questions, new to the efi world. Then, when you experience the high idle, note if the IAC number has increased. I drove it a bunch more yesterday afternoon/evening and the same thing happened several times. It will need to see it again and again. When I drive with warm engine the IAC is at 30% when pushing gas, but shouldn't it be at 0%? 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. Ilike a few othersam having idle issues. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. 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. Sniper EFI Idle Tuning. Capability Range: Advanced My dad wanted to recheck the timing so I set the Static Timing at 15 and it runs perfect. And since they really had an insanely-tight monetary and real estate budget in the Sniper EFI System, it is unlikely that the added something that wasn't absolutely necessary--and then forgot to use it..And you are spot on about the little Earl's gauge with optional -6 AN port. 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! Glad to hear that things are working well! engine works beautiful, the car runs a lot, but suddenly, the engine does that. I will confirm TDC with balancer but I have had balancer off and timed it before and after with same results. It shuts off when coming to a stop sign, at any cruising speed and romdomly at idle in park but never when excelerating. Are these compatible enough? At any rate, once the setting was moved up, the RPM jumped right to the target RPM and was solved. i would have been happy to answer there. And so glad you guys are enjoying the Sniper EFI system. Your comment doesn't imply any sort of problem that would make me give up on idle timing control. 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. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. Two months fighting, cursing, not getting any help from Holley OR the forum, and a stupid little tin plate. I presume your idle speed table doesn't increase at 200 degrees? Technically it is a warranty-voiding maneuver so proceed at your own risk. Yes, it will talk to you--but not with words. The small rubber plug had a leak. It's hard to know what the previous owner did right versus wrong. 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. They are prone to be inaccurate. I keep doing that with the same result. After it starts it idles around my 960rpm setting + or - 100rpm. Drive great and idles perfect at stop signs. Properly configured, the Sniper does a fantastic job of responding to the transition from Park to Drive. All times are GMT-6. Your mechanical advance will naturally change the timing a bit but it should be fairly close. I have replaced the IAC motor and the problem remains. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. I keep doing that with the same result. 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! 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. Holley documentation and videos didn't work and the $300 I paid for "expert" tuning didn't work either. 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. Any suggestions? One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. Sometimes an engine can produce enough vacuum to pull the secondaries open slightly. I have been reading these posts and have learned a lot. Really appreciate the amount of learning im getting off here. When I first told him to check for leaks he looked back there and said "all good". You can manually set it 57 after you run the Wizard if required. 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. Plus, you can email that file to me and I can be of more help. The AFR was pretty consistent around 13. 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 driven a stand-alone transmission controller for the 4L60E in my (then) Sniper-equipped '95 GMC pickup using the Sniper TPS with complete success. 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. By the way your site and your accessory products are nice. Earl's Mechanical Fuel Pressure GaugeI could use that for a quick troubleshooting for 1/3rd the cost of the Holley one. started up the engine. Not to bandstand here but this is the point when where you bought your system is so important. We offer some tips to help with that. On startup- cold or hot, I get a 2 second high idle of about 1500 RPM before normal set idle of 750 RPM happens. I think you will find that it will learn its way through this. You might have a bad O2 sensor, really bad exhaust leak or a problem with the ECU. 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. Running the vacuum advance and of course I time it disconnected. My issue is that the TP% will not reset with key cycle and its idleing at 9% TP. Lubricate the linkage so there isn't as much native resistance. TP range is normal goes up to about 90% with throttle pedal to the floor. I know this is old, but I bought and installed a Sniper kit in 9/18. I got it home, checked it all over, everything is hooked up correctly. I was shocked to see it at 95lbs!! Start engine let it warm up to 160, learn mode is learning. This car has never idled under 900 without stalling with 3 carbs and does the same thing with sniper edit. Pw. Hopefully replacing the pump again will resolve both issues. I straightened that out, got it running and that's where it goes downhill. The engine has 14: 1 compression ratio, we can not use gasoline. You can drop it down and you will find it will behave more like you expect. 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. They also recommended that their ground be spliced into the Sniper ground as close to the Sniper as possible. https://www.youtube.com/watch?v=2JpHlS1ymBc, If this is your first visit, be sure to = 2.34 Ran 2 Holley carbs and an Edelbrock. 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. A good example of why it's so important to run a good pre filter in the fuel line. I also noted that after some time, I could change those values as I saw fit. The window you saw in the image above pops up. Fortunately, I have an article that goes into this in some detail. The IAC should display a 2-8% to bring the idle up to the actual target. If your fuel pressure regulator has failed (and they often fail by blocking return fuel and maxing your fuel pressure) then it could lead to rich idle, particularly until your engine gets up to temp. If you are idling at 2100 RPM (based on a default IAC Hold position of 30%) and your target idle speed is 900, then the ECU is not going to try to idle down. That is certainly not normal! If I try and get the 2-10% i get all the way up to 1200 rpm. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. I'll have to check again tomorrow. Yes, let me know how that setup process works. Interesting question. 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. When I covered the IAC with my finger, the RPM dropped so low it stalled. And the rather cavalier "Absolutely!" Chris---I am contemplating replacing my Holley 750 on my new low vacuum 600 HP 496 with the Holley Sniper FI system. Do I have to hook up sniper ac wire to relay or should iac pick up idle? Thanks for all your help Chris! The throttle plates are misaligned. I keep wondering how it was running so good with I have a 406SBC that does most everything right with this sniper setup. 3 different fuel pumps. Relatively new Sniper EFI install on a '69 Mustang 302. hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I The RPM would increase for no reason. Contact whomever sold you your system or Holley directly. Could you provide me with some things to check or some things to adjust? I was 20 minutes into a drive yesterday when all of the sudden the RPM increased not commanded. Not good.There isn't set solution here that works for all engines. What could be the cause?