holley sniper efi iac problems

your IAC is at zero. Yes its at 95lbs, needless to say he promised a new regulator would be in the 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! It starts cold fine, its just when its hot. 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. Do I have to hook up sniper ac wire to relay or should iac pick up idle? I certainly appreciate your frustration (as well as your wife's!) 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. At any rate, once the setting was moved up, the RPM jumped right to the target RPM and was solved. 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. This curve turns the idle speed down as the engine warms. After only running for about 15 minutes or so the system starts to fail stalling the motor. I've been trying to correct that 1% small issue/annoyance. first attempt but as it tries to idle down to the target RPMsit can never even 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. I have quadruple checked my wiring and am certain it's correct. Wish I had bought my sniper from you, but unfortunately didnt. RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the :-). Sometimes it sounds like it wants to crank at the start but runs out of gas. Could be a bad IAC motor, replace it and see if that solves the problem. The Sniper EFI system looks at the closed-loop fuel compensation required to reach your target AFR. I didn't find your site until I was having trouble. Nice to meet you. The biggest issue is these problems are intermittent meaning they do not occur all the time. Genuine Walbro fuel pumps are virtually bullet-proof. It could be a problem with the power/ground for the Sniper but much more commonly this is a result of too much RFI. Resistance results in heat and heat results in more resistance. 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. All times are GMT-6. That way you can get into that part of the table that needs tuning, and you can watch your learn numbers grow. Hello, Chris, thanks for the help.I have not installed the software yet, and I'm having trouble with two cars. The tps will not auto reset to zero. But I am having troubles.When stepping on the accelerator slightly with idling, it will be 2000 RPM all the time. To keep it running in gear, I have to bump the neutral idle up just over 1000 RPM. Bolt-on carburetor style EFI for your classic car or truck. 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. *Possible delays due to Covid-19 click for more information. :-). It is working fine when you restart the car, controlling idle perfectly at 8 steps open so it is unlikely to fail when the car warms up--or correct itself instantly when you restart it..So, if you don't have any vacuum leak, and the throttle plates are fully closed, the only thing I can guess is something is causing your ignition timing to change. (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. 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. View Holley Sniper EFI Self-Tuning Kit - Shiny Finish. :-). Yes, you are correct. When I covered the IAC with my finger, the RPM dropped so low it stalled. The Sniper resets the TPS to 0% each time that you key the system on. It sounds a little different from mine, since it commands a 1300 or so increase intermittently. You are aware of the idle-up problem. Running a bbc with coil - my timing is perfect. Ultimately, it is about making the pedal softer, particularly at initial throttle opening. Now, 1% on the TPS isn't a problem, but when it goes to 2% (which is inevitable if you have RFI moving it to 1%) then the IAC is going to go to it's hold position (30% by default) and the engine is going to rev up. Camshaft is M-6250-B303 .480 lift intake & exhaust, duration at .050 is 224 degrees for intake & exhaust. At 0% it shouldn't be sucking any air through that port, correct? Installed sniper on 65 galaxie. Don't know if I should put this in a separate post. And thanks again for taking your time to answer these questions. But, whether your vendor provides you with tech support or sends you to Holley, I'd start by getting them a data log and asking for some insight. Yes it is controlling the timing and I had issues at first and it controlled the idle just fine. shut truck off. Changing the rpm curve and target rpm has no effect. I have now determined with the TPS the noise correlates with the opening of the secondary butterflies. 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. It might be necessary to insulate or re-route your fuel lines if this can't be solved any other way. If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. That's not the IAC Hold Position, it's a percentage value. Holley Sniper Iac Delete Note that Brazilian gasoline has 27% ethyl alcohol. Hello 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. I'm new to EFI and have no idea what to try next. 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. idles good, runs amazing. Even at 0% it's sucking a bunch of air through the IAC port. Any suggestions? 30 minutes later CTS reads 161, start engine Idle is jumping from 450 (almost stall) to 1500, IAC is jumping all over 10 90. But once you come off the throttle there is a minimum RPM that the ECU wants to see before it releases the IAC from the park position and that is normally 1000 RPM over the target idle. Holley EFI Electronic Fuel Pressure Gauge, article on choosing between Sniper and Terminator X throttle body solutions. Cl. Hopefully replacing the pump again will resolve both issuesWhoa. Turning it off and back on would reset it, and then it would work as advertised for a while. normal city driving, I no longer have other problems I had with the original Add To Cart. Wish I knew about it before I made my purchase. Note: The IAC breather hole is the roughly 1/4-inch triangular hole that sits above and between the secondaries. ?I never had my Carb Cold start RPM any higher then 1600 RPM.THANK YOU. 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. holley efi. 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. 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.) Hi Chris thanks in advance for any tips. And so glad you guys are enjoying the Sniper EFI system. It's all part of the pleasure of EFI. I am having an issue with the IAC on the Sniper. If that happens then follow my 10-step process shown above. In the context of the Sniper the AFR that is being displayed is the AFR of ethanol-free gasoline based on the lambda that is being read by the AFR. 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. applies here because it is so important to realize that just because the IAC Thank you for your input. Any suggestions would be appreciated. Holley will take a look and tell you you have RFI and wish you good luck in finding it. Does anyone have photos of this additional return spring they installed? the gas it catches itself and runs fine at slower speeds. I have tried your 10-step idle adjust and ive adjusted the idle curve. Idle was around 1000 mark and iac 0. 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. In fact, it is those users who seem to end up most impressed with the system. Thanks! Please let us know how this works out for you! Enjoy! In this short video you learn to replace the IAC. I would start by removing the progressive linkage. 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. I've not heard of any others with this exact issue so I don't think it is a common problem. 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. That is not the way to go. Hey Chris! Plus, you can email that file to me and I can be of more help. This is a mighty big subject for a blog post reply, I should probably start doing some videos on this. Sometimes an engine can produce enough vacuum to pull the secondaries open slightly. Don't try to correct for the fuel. The IAC is hanging open and not really at 0. Hello Chris. I asked him a million questions and waited a long time to save up before purchasing the system and I have asked a lot of questions throughout the installation process. Hang in there--you can do it. Overview. By the way, this is a new installation on a 69 Camaro, stock 350, dual sync, etc. 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. What should I be looking at to calm this down? 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. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? The engine ran so good, I would have never suspected the Fuel Pressure to be an With the vehicle in neutral, adjust the idle screw until the IAC Position reads between 2 and 10%. any advise would be appreciated. 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. When I turn it off and try to restart it just cranks. When I see that your TPS is 1%, that tells me that you may have an RFI problem. If you've been running a filter then you have to wonder if you have a legitimate Walbro pump.If you install a new pump and the noise is still coming from the Sniper EFI System then only the dealer who sold you your system can help you. So the issue Im having is low idle. I have driven it a few times maybe 100 miles or so. Sniper setting is Stock camshaft. You might have a bad O2 sensor, really bad exhaust leak or a problem with the ECU. The RPM would increase for no reason. back to trying to zero down an idle. Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. 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. All times are GMT-6. Generally, one of two things: a stuck throttle or noise on the TPS signal. The 5-6 times it has happened now have been after the car has been running for at least 20 minutes. When you set the Static Timing to 15, what did you read with the timing light? THANK YOU for the "First--Check Your Idle Speed Curve Setting!" Somehow air is entering the engine that was not entering the engine when you originally set the idle speed screw. If the IAC is zero, and if putting your finger over the IAC port doesn't lower it, then it's not the IAC circuit. 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. It then idles up from 750 to 1100. The "Gauge Text" is what would be shown on a 2-1/16 gauge or the Avenger handheld display. Bolt-on carburetor style EFI for your classic car or truck. Those don't impact the way the engine runs and can cause the whistle sound you describe. Look over all of your vacuum lines and fittings. In some cases, you may only be able to put as little as 10 RPM between the hard idle and the target idle. The jack-rabbit start can usually be minimized by adjusting the throttle linkage. I'm so glad you found this helpful--that makes my day!Don't get too concerned about the specific learn percentage. 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. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. It could be a couple of things. The Street/Strip and race cam setups tend to be too rich initially. Have you checked your fuel filter and made sure it's not plugged?If both of these are okay you're going to have to find a way to monitor your fuel pressure while under load. Glad to hear that you have timing control enabled, Gary. It is easily solved by installing a four-hole gasket or four-hole spacer (depending on your hood clearance issues.) I never had a problem with this. 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. Just add 5 or 10 degrees of advance and see if it doesn't idle better. When I cover it with my hands, it gets quieter. I think you will find that it will learn its way through this. EFI Systems based on Holley's world-class Dominator and HP ECU's. There's a procedure there I can share with you if you'd like.. When I drive with warm engine the IAC is at 30% when pushing gas, but shouldn't it be at 0%? Did you find this enlightening? 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 I put the vehicle in gear the idle gets higher with temp. 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 Can the return line be an issue?I have had 2 faulty gpa-4 255 walbro pumps go bad. Second, Holley just released over the weekend a video on how to implement a flex fuel sensor on their HP and Dominator ECU's. Kind of cuts into forum time. I am at the point where I almost insist that every Sniper EFI System owner purchase one of these. 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. Then you can take a close look at the IAC and see if it is opening. When I put it in gear, it drops so low that it will stall if I don't add throttle. Fortunately, I have an article that goes into this in some detail. I have been able to get it pretty P.S. 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. itself out and hold idleeventually stalling. I also raised idle at Park a bit with the idle screw. This is actually more troubling than the sound you originally described. All of the wiring exits below the rear fuel injector cover, for a completely stealth installation. 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. Now that you've got your IAC set I'm going to recommend that you run your setup wizard again, which will reset the ECU to the default settings. Super helpful and knowledgeable. Are these compatible enough? Hi Chris. around 45 mph it bogs down, catches itself, bogs, catches, bogs and catches. mean that the IAC is causing it. I would gladly engage with you to solve this but ultimately you are going to need to go through whomever you purchased the system if a warranty return is in order. Also its extremely rich at idle. 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. idle counts from 0. Is there away to lean the idle out? 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. 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. I installed the Holley Sniper in my Chevelle this winter with a brand new BluePrint 496. Across the board, all of our customers say how impressed they were that it started and ran right out of the box just by following the simple installation instructions. We are using Target AFR of 9.0: 1, Fuel Base approximately 40% higher. The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. The only way to do this is by installing a mechanical fuel pressure gauge. And yes, monitoring the fuel pressure is the right answer. I'd say make sure you buy from someone who can give you good after-purchase help (hint!) The tps has slotted holes, can you adjust it to get to zero? One of the best Ive seen so far. Or, at least, it should. 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 installed a sniper efi system on my 1969 Camaro. As I said I didn't buy from you so you don't owe me anything. Holley documentation and videos didn't work and the $300 I paid for "expert" tuning didn't work either. :-). The IAC reads 36 when at idle fully warmed up. However, I always preach to never touch any of the controls on the handheld until you have a couple hundred miles on the engine in a range of driving situations. For the first couple of drives it was running well, Sniper EFI was working exactly as advertised. I set the AFR at 13.5 and all is good now. Therefore The iac will always be at 10% now, correct? I've increased the IAC rampdown time to 8 seconds to try to combat this, but wondering if it will correct itself over time or if I need to possibly replace this TP sensor. Cracked casing from a side cover screw being installed crossed threaded. That's what you're seeing. Copyright 2022 Holley Performance Products, Inc. All right reserved. It is reliant on the data acquired by the included wideband oxygen sensor. We will definitely be sticking with Holley from here on out for future retro-fits. 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. 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. EFI parts, including the throttle body, and the problem persists.Please give me a hand. Full product line and accessories at excellent pricing. Intermittent stalling usually points to radio frequency or electro-magnetic intereference (RFI/EMI). The throttle blade adjustment is at 2-6% at hot idle, and with warm engine 185F. A couple of possibilities that come to mind in order of likelihood: Im having an issue with what I think is the Iac. 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. 680-700.I can't find any reason other than it looses where it is in the firmware with But now that Terminator X is available, I highly recommend going that route. Drives just fine but won't stay running unless I keep my foot on the gas. Ensure there isn't a vacuum leak causing the IAC Position to drop to 0%. Incorrect connections will result in excessive resistance. The fix? installing and cruising down the highway 70 mph I just wonder if all I have to do Your AFR is pegged lean. 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). The only other thing I changed was accel enrich but whatever way I go doesn't seem to change anything unless I change it drastically. Turned it off and on again. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. I have an adapter on the manifold for squarebore to spreadbore and then a phenolic spacer.

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