日本語My issue is that when Im in stop and go traffic, I can let off the clutch and the engine revs and doesnt quite want to come back to idle. Super helpful and knowledgeable. Chris thank you for the info. Unless you have ignition control enabled, that is the only thing it can do to reduce the idle.Realize the only things that can cause the car to idle up as you describe are air and ignition advance. It shuts off when coming to a stop sign, at any cruising speed and romdomly at idle in park but never when excelerating. 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. If your RPM is 2000, your TPS is 0, and your IAC is not closing, then there is some problem. Do I need to try taping up the IAC port and setting the idle off the idle screw? That is likely just confusing the issue.Instead, choose whichever setup most resembles your camshaft and stick with that. When the idle speed screw is turned all the way out there should be just enough room between the bore and the blade to catch your fingernail. I installed my Sniper and the engine fired up great. Thanks for the info Chris. Thanks Again for your help. At any rate, once the setting was moved up, the RPM jumped right to the target RPM and was solved. I will a, Scott has been very helpful and informative on guiding me through the purchasing and installation of my terminator X max system. Once you know that then you can work on those problems. It would be possible to set up a 1D or 2D table and do something like this, so if you've gotten into these advanced setups then that would be another thing to check.If neither of these work then I'd recommend that you do a data log of the engine idling as the temperature is reaching and then exceeding 200 degrees. We're having trouble with a Ford Maverick 302 V8, using ethanol. Cheers Darren. The hold position is part of the response that keeps the car from dying when you come off the throttle. This may require shortening or lengthening a rod. There are two ways to address this--you can let the system learn or you can manually adjust the acceleration enrichment. You could install the Holley Dual-Sync Distributor and let the Sniper control your timing. You will need to change the -40 degree idle speed setting again but I recommend not touching anything else. Should the iac% fluctuate? 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. 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. Really appreciate the amount of learning im getting off here. 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. Are these compatible enough? A good example of why it's so important to run a good pre filter in the fuel line. 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. 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. Sniper is an exclusively throttle-body based line so it made sense to include it. To do this, open up the Initial Startup gauge screen that was used in section 17.0. Let's start by not assuming anything. NOTE: Do not attempt to set the target idle speed and IAC position until the engine is above 160F! Were the additional load a simple step function it would be challenge enough for the ECU to gracefully increase the engine speed without overshooting. It appears that I could now use the dongle and a laptop to custom tune for idle issues if needed. Find a lower price anywhere and we'll beat it by 5%! Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to One thing you need to sync the timing and set the inductive delay. Since that has long been corrected we have moved that information to the bottom of the article.). !I called Holley today, and before I could even described the symptoms the Copyright 2022 Holley Performance Products, Inc. All right reserved. At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. WIthout knowing quite a bit more it will be more than challenging for you to identify the problem and solve it.Fortunately, Holley provides their amazing Sniper Software. Ok, so I'm stumped! You're going to have to clean up the wiring in your engine compartment, In particular, look for spark plug wires that might be running near your throttle position sensor. It is a common one. When I covered the IAC with my finger, the RPM dropped so low it stalled. The throttle blade adjustment is at 2-6% at hot idle, and with warm engine 185F. = 2.34 We've already tried adjusting the Acceleration Enrichment chart in all ways, going up and down, RoC Blanking, everything, it has no effect. There is no real mystery here. Running the vacuum advance and of course I time it disconnected. It sounds a little different from mine, since it commands a 1300 or so increase intermittently. My issue is that the TP% will not reset with key cycle and its idleing at 9% TP. The Sniper resets the TPS to 0% each time that you key the system on. At that point the tps is pretty high, then shut the ignition off, pull the tape restart the engine and idle goes into hold mode and idle is through the roof. Idle : IAC Rampdown : IAC hold positionChange this by maybe 2% in either direction. any advise would be appreciated. What might cause the TPS to go to 2%? Sniper setting is Stock camshaft. If I put the vehicle in gear the idle gets higher with temp. Capability Range: Advanced :-). I, too, wish you'd bought your Sniper from us! Idle was back to normal but iac was at 0. the issue A couple of possibilities that come to mind in order of likelihood: Im having an issue with what I think is the Iac. The Sniper ECU can use the timing to help maintain the idle speed and that will definitely be useful in that transition from Park/Neutral to Drive.If you don't have ECU-controlled timing, or if you do and it's not fully compensating, it may be necessary to increase your target idle slightly. You could go either way.. Car has run perfect every time and has never hesitated or stalled since. I've been trying to correct that 1% small issue/annoyance. But there are several degrees of play there in which it should still work fine. Holley Sniper Iac Delete Can the return line be an issue?I have had 2 faulty gpa-4 255 walbro pumps go bad. Hey Tommy, we've got at least one thing in common. :-) Just don't let the parts go flying. The engine ran so good, I would have never suspected the Fuel Pressure to be an Note that Brazilian gasoline has 27% ethyl alcohol. This page was generated at 12:26 AM. The engine has 14: 1 compression ratio, we can not use gasoline. Chris, I recently installed my Sniper and have an intermittent idle problem. It will need to see it again and again. Observing the temperature on the 3.5-inch handheld (only), wait for the temperature to achieve 160 degrees F. Once above 160 degrees, turn the idle speed screw so that the idle is about 50 RPM below your target idle speed set in step 1, above. The manifold pressure increases with the throttle opening but the RPMs are still low. The fact that it ran so (at times) with 90+ PSI fuel pressure is a testimony to the Holley's closed-loop technology. :-). Turning it off and back on would reset it, and then it would work as advertised for a while. You have to remove all hoses in order to debug the problem. I guess we can't have everything. After it starts it idles around my 960rpm setting + or - 100rpm. Any suggestions would be appreciated. But when you have it then you can look for exactly what the IAC is doing at that point, and if there is anything that might lead to this happening. 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. 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. Even at 0% it's sucking a bunch of air through the IAC port. Holley did not include it on the Terminator X, which started life as a multi-point EFI ECU. The first thing I'd do is check your fuel pressure with a gauge like this. lower until I turn down the set screw. I am at the point where I almost insist that every Sniper EFI System owner purchase one of these. 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. Jun 12, 2021. Give them a call and if they are unable to provide customer support the contact the Holley tech support line at 1-866-464-6553. That Even then, recognize that over time the IAC will need to be readjusted to compensate for minor changes that will cause it to drift. 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. (If you do this you will need to reset the -40 degree setting mentioned at the top of this article. Be sure to re-enable it once you get your idle tuned. Thanks for the great question! 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. Since a key cycle resets it to 0 and out to 30 or wherever Ran 2 Holley carbs and an Edelbrock. I installed a Holley Sniper on my Ford Maverick 302 V8. Doesn't want to start, runs like crap. 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. I have double checked everythingincluding fuel pressureand have followed the directions to a T.I plan on trying your 10 step process as soon as I get a chance. This is more of a bit of a reality check. What could be the cause? Remember that as an EFI System Pro customer you have access to me at any time via my cell phone. 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. 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. It sounds to me like it is way retarded.In the event that the timing is right then take a look at your AFR--the actual AFR, not the target. Yes its at 95lbs, needless to say he promised a new regulator would be in the After speaking with Holley Tech Support and Tech Support from where I purchased the systemthey decided to replace it. We'll also be contacting you for future purchases now that I've discovered you! )Since this isn't a consistent issue with all Snipers that tells me that different IAC settings tend to make the whistle. If that tested out okay then I can really guess that there might be some sort of intermittent, temporary RFI. It is simply for the benefit of the user. Thank you in advance for your help and providing us rookies with your Remove the tape from the IAC breather hole and restart the engine. Properly configured, the Sniper does a fantastic job of responding to the transition from Park to Drive. The tps will not auto reset to zero. I go into much more detail about that in this article on startup tuning. 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. Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. mail today. 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. (Plus they it just looks way cool in your engine compartment!) I keep doing that with the same result. started up the engine. This car has never idled under 900 without stalling with 3 carbs and does the same thing with sniper edit. It only comes back to normal if I turn the engine off and on again. If there is an issue with using the Sniper EFI TPS signal, is there a remote TPS or an adaptor for the Sniper EFI that allows the TPS signal to be accessed for the transmission. 400 engine, C6 3 speed automatic, with standard canister coil for ignition, and Then why don't you Get On The List for Emails Straight From Our Pro? If it creates an issue (not normally the case) then you'll know. My IAC was constantly at 100% at idle. 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. There is a chance that the IAC is open but displaying 0% so start by putting your finger over the IAC opening. Cracked casing from a side cover screw being installed crossed threaded. He thought that something was wrong because when he set the idle 50 RPM below his target the resulting IAC postion was far too big. I have an entire article on choosing between Sniper and Terminator X throttle body solutions and while Sniper is still a sound choice for some applications, Terminator X (with transmission control) is hands-down the way to go for those who need that. So I have been driving it for about 400 miles now to numerous car shows and going out for cruises around town, trying to work some of the bugs out from everything we did this winter, but I notice when I take off from a stop sign or I cruise at a very low speed (say30 mph) it seems to be very boggy from no throttle to about 1/8th throttle. After this whole process, the car normally rotates without a very abrupt pedal. Not to bandstand here but this is the point when where you bought your system is so important. Some have suggested mis-setting sets the idle speed at 850 RPM but I suspect it is not a fixed number but rather a delta of about 300 RPM above the target. But if you will just advance the timing at idle and see if it makes a difference then that will tell you what you need to know. 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. I' m going to put the 3rd new pump this coming friday. Advanced throttle body injection systems capable of transmission control and more. 90% of time with engine hot. it seems to ramp to 60 psi on the initial prime, but as soon as the motor start the psi spikes.I guess a workaround would be an inline return/filter regulator? But he kept having problems so eventually he did a complete check and then he found the problem. The warmer the motor, the higher the idle will be at this point. The first 250-300 miles were amazing as the Sniper EFI worked flawlessly. 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 am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. Sniper EFI offers superior throttle response and wide-open throttle power. Sometimes an engine can produce enough vacuum to pull the secondaries open slightly. Your issues are likely related to one of these two things. EFI parts, including the throttle body, and the problem persists.Please give me a hand. Two things to keep in mind as you do that. 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. You will have to do this until the TPS stays at 0% when the throttle is closed. Yes it is controlling the timing and I had issues at first and it controlled the idle just fine. When I cover it with my hands, it gets quieter. Everything was working perfectly and I shut off the engine. Any idea's? 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. I've been having problems with my sniper efi just shutting off. The link above includes the option to buy a -6 AN This was an issue in the earliest version of the Sniper firmware. check out the. Hi I wish I had bought from you but I didn't find this site until now. 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. The noise is definitely coming OUT of the throttle body. :-). From herethe cycle continues and I am Turning off and then on again, the engine returns to normal. The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. (Grease can sometimes do the same thing as a more permanent gasket sealer without making the removal of the air cleaner such a pain.). This is extremely unreliable afrer warm. If I go any more it will ping. I.e. 3 different fuel pumps. All in all, considering the system has been installed for less than 2 hours drive time we're BLOWN AWAY at how quickly it is "learning" this engine. I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. The latest was changing the power brake booster.Today I drove it to work and no issues at all. Maybe give it a half-turn before you start it and then start and tweak. 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. :-). The problem I believe this is creating is after I start vehicle (and its still in park), the IAC drops down to my hold percentage of 10% (since throttle % is not 0) before engine is warm and therefore causing the engine to stall out. and when I close the IAC's hole with his finger, the engine is normal.The data on the touch screen I see are:AFR, A / F = 35.6 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. Glad to hear that you have timing control enabled, Gary. 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. 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. While you have over 200 miles on the system, you must realize that in the part of the map where the ECU finds itself during lanches you might only have a total of 5-10 seconds in any given cell. 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. 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. The IAC going to 30 is normal. 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. It does this with the engine off. Your comment doesn't imply any sort of problem that would make me give up on idle timing control. If your TPS has snuck up to 2% then your IAC will be at the hold position, which by default is 30%. 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.) 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. 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. We can not hit it at all, we hit the pedal abruptly, the engine gives a lot of excess fuel, the AFR gets super poor at first, the car stops, then the AFR gets super rich and the car runs until it cleans up. TP range is normal goes up to about 90% with throttle pedal to the floor. Good I have driven it a few times maybe 100 miles or so. :-). These aren't generic newsletters either but instead personalized emails. AGAIN This is Intermittent meaning on a recent trip I stopped 3 times and issued occurred once. I don't want to go on too long here but once you know if you're trying to add or remove fuel, there are a couple of ways to go. Do I have to hook up sniper ac wire to relay or should iac pick up idle? itself out and hold idleeventually stalling. The RPM would increase for no reason. What I can't explain is why your TPS is acting so randomly. It's not that they (or any other manufacturer) is 100% perfect. I recently bought the car with the EFI system on it. 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!) When I put it in park the idle RPM was 2100-2200 each time. Replacement Idle Air Control (IAC) Motor for Sniper EFI TBI Systems, Sniper 90/92/102mm Throttle Bodies, Terminator TBI, Avenger 4bbl TBI, HP 4bbl TBI, Commander 950 & Digital Pro-Jection Systems. Mechanical Fuel Pressure Gauge on the inlet of your Sniper, now is the time. One of them might be faulty. 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. Generally, one of two things: a stuck throttle or noise on the TPS signal. We are running a Sniper on my mates 355ci small block V8 & so far he is very impressed ! Setup: 1965 Impala SS; ZZ6 Crate Engine, EFI Distributor. Without it you are working in the dark. So check that timing and I think that you're going to find you need a good bit of advance. I took some pics of the sensors page this morning after the car warmed up. When running it will only stay in closed loop and learn at idle. carburetor setup, but it does blow when I can't jump on the highway like I use 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. It works instantly for him.If that fixes your problem then you have a starting place. Your mechanical advance will naturally change the timing a bit but it should be fairly close. You will find a startup IAC percentage, an amount of time it holds at that percentage, and an amount of time it takes to idle down to the normal idle speed.By default, that number is 50% at normal operating temperature.
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