Took it for a lap around the block and came back. I will try the other stuff when I get off work. Or is there something else I should I have adjusted many settings and eventually mess it up and go back to the original map. 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. Save Share. 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. I then saw you guys have an awesome little gauge that can hookup inline to the snipers existing fuel feed?? 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. They also worked with me on a sale I missed and price matched those parts. Can the return line be an issue?I have had 2 faulty gpa-4 255 walbro pumps go bad. 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. All of the wiring exits below the rear fuel injector cover, for a completely stealth installation. 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. 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. I enalble the idle timing control and fired it back up Iac was at 32% but it would come back down after a bit to around 26%. Shut off car/restart and it's back to idle at We are running a Sniper on my mates 355ci small block V8 & so far he is very impressed ! It shuts off when coming to a stop sign, at any cruising speed and romdomly at idle in park but never when excelerating. Not good.There isn't set solution here that works for all engines. It then started working normally again. I have installed my Sniper and the car runs great. This car has never idled under 900 without stalling with 3 carbs and does the same thing with sniper edit. carburetor setup, but it does blow when I can't jump on the highway like I use ps. This is very disappointing as people love to hear the motor while the hood is open.Thanks Jon. any ideas? Drop the IAC parked position a bit at each temperature point and sort of back into the solution. Any idea's? 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. Setup: 1965 Impala SS; ZZ6 Crate Engine, EFI Distributor. Fortunately, I have an article that goes into this in some detail. That is the only way to fly. 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. Do you have a PCV on the engine? Copyright 2022 Holley Performance Products, Inc. All right reserved. The fuel pump is mounted under rocker panel as low as possible and far away from any heat. Car was running great initially. Also what would you say a desired idle should be for a 3 speed automatic ford? Turned it off and on again. Is there any chance that your timing has changed since you installed your Sniper? And the rather cavalier "Absolutely!" OK, I did the baseline idle speed screw setting. Did your process to adjust idle to 860. Somehow air is entering the engine that was not entering the engine when you originally set the idle speed screw. But if the idle is a little bit higher then it doesn't have to jump quite as much in response to the load, and tends to react a little bit more smoothly. Even then, recognize that over time the IAC will need to be readjusted to compensate for minor changes that will cause it to drift. I believe because the TPS is not registering. The team at EFI pro are some of the best I have ever dealt with when coming to ordering parts or having the knowledge to answer any question you may have. I recommend confirming there is no throttle linkage issue first. To be honest, you sound like an ideal candidate for Sniper ECU ignition timing control. No air should be able to pass. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. 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. If that happens then follow my 10-step process shown above. 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. Chris---I am contemplating replacing my Holley 750 on my new low vacuum 600 HP 496 with the Holley Sniper FI system. *Possible delays due to Covid-19 click for more information. After only running for about 15 minutes or so the system starts to fail stalling the motor. Generally, one of two things: a stuck throttle or noise on the TPS signal. If i set the idle to 750, the only way i can get it there is to turn the idle screw all the way out but then its at 0 iac. Do I have to hook up sniper ac wire to relay or should iac pick up idle? Holley Sniper IAC Problem 04-26-2018, 11:30 AM Hello. I had HIGH Idle issue and fixing this curve FIXED the ISSUE --- THANK YOUCan you explain what "Current Learn % means, after finally fixing the idle problem this % jump from -1 to -30% in about 5 minutes at idle with CTS @ about 170.Also when starting the car at hot the engine goes to about 2300+ RPM for a few seconds then crashes down to my Hot idle speed of 950 -- bounces a little and then smooths out. I think in some of the Wizards with the handheld it doesn't use 57.5 as the default. Perfectif you have the original synchronous linkage. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. Therefore The iac will always be at 10% now, correct? Two things to keep in mind as you do that. And your understanding of how the throttle position affects idle is exactly correct. 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. As I would slow down for a stop sign or stop light, the car would run really rough and the idle did not want to come down. The AFR was pretty consistent around 13. Others might require 60 RPM. I recently detached the TP sensor from the side of the sniper to physically move it and it still would struggle to get to 0%. I appreciate everything you are saying. 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. )Take a look at your AFR during the starting process. I'll bet you find that you can get it working great without any manual tuning. Which means you either need to increase that number or increase the ramp decay time. Seems to be working. 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. My car will not idle right until it gets to around 130 -140 degrees. So the issue Im having is low idle. Hi. Ultimately, it is about making the pedal softer, particularly at initial throttle opening. 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. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? Does anyone have photos of this additional return spring they installed? Hello Chris. Don't make any changes more than about 10% and keep the same basic shape as the original (High/flat below 20 degrees, sloped downward up to 180 degress, and then flat again above that.) Intake has been on and off 3 times no change. Don't try to correct for the fuel. Holley Sniper Iac Delete If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. Good When I am coming to a stop, the rpms will hang at 1200-1500 rpms. You're going to have to get this fixed or it's going to cause even more problems than the high idle. 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. The engine has 14: 1 compression ratio, we can not use gasoline. The ticking is inline with the fuel pressure I feel squeezing both the fuel return & delivery lines (like a heartbeat). I'd really appreciate some help. Pricing was reasonable, shipping was prompt and Chris helped me with a wiring question during my install. check out the. Holley EFI Electronic Fuel Pressure Gauge, article on choosing between Sniper and Terminator X throttle body solutions. This is normally used as an A/C idle-up circuit. Since the shield was put on, not a single problem, not one. I think that the more important point is that Holley kept sending him units until everything was working. (Note: in the original version of this post we had a section about checking the idle speed curve setting. 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. Software: Idle > IAC Settings > Idle Spark, Handheld: Tuning > Advanced > Advanced Idle > Idle Spark, After completing this 10-step process, if the temperature displayed on the handheld is still above 160 degrees the engine should go right to it's target. I believe that for the HyperSpark the Reference Angle should be 57.5. I think I figured some of my problems outI'll try to explain. I was 20 minutes into a drive yesterday when all of the sudden the RPM increased not commanded. Ensure there isn't a vacuum leak causing the IAC Position to drop to 0%. Since a key cycle resets it to 0 and out to 30 or wherever 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. 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 this short video you learn to replace the IAC. )Since this isn't a consistent issue with all Snipers that tells me that different IAC settings tend to make the whistle. When I turn the key on I can hear it prime, but I don't think im getting enough fuel. 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. Idles ok, runs great cruising, but from a stand still or downshifting and making a turn, when I get back into it, it wants to fall on its face. Thanks for sharing that, Jason--great info! your IAC is at zero. When you open your IAC to 30% you are naturally going to have a high idle condition. 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. I went on the good ole interweb and found your website which was VERY helpful! Throttle body mounted ECU - no extra boxes to mount. Sorry I didn't buy from you but I didn't know you had sold them. All times are GMT-6. Let's start by not assuming anything. I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. It is easily solved by installing a four-hole gasket or four-hole spacer (depending on your hood clearance issues.) The hold position is part of the response that keeps the car from dying when you come off the throttle. Overview. The last 2 times have been shorter and one time the high idle was around 1400, this time around 1100. However I do have a couple of issues I hope you can help me resolve. That And, hopefully, within those degrees you will find a place where you don't get the whistle. Have you ever experienced a high idle once the engine reaches 200 degrees?Ive set my idle the way you said and it works great until the engine reaches 200 degrees. I have an adapter on the manifold for squarebore to spreadbore and then a phenolic spacer. If you use your handheld to go here: (Grease can sometimes do the same thing as a more permanent gasket sealer without making the removal of the air cleaner such a pain.). Two months fighting, cursing, not getting any help from Holley OR the forum, and a stupid little tin plate. 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. I'd say make sure you buy from someone who can give you good after-purchase help (hint!) We have never had that problem with any of the units that we have shipped. I go into much more detail about that in this article on startup tuning. Idle : IAC Rampdown : IAC hold positionChange this by maybe 2% in either direction. Holley Idle Air Control Motor Idle Air Control Motor Fits the Following Applications: Sniper EFI 90 mm, 92 mm, 102 mm Throttle Bodies Digital Pro-Jection Systems Avenger 4-bbl TBI Commander 950 Terminator TBI Thanks for any help. I also raised idle at Park a bit with the idle screw. I am at the point where I almost insist that every Sniper EFI System owner purchase one of these. Any ideas here? If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. As I said above, you could have a bad IAC, but then again, the IAC might be fine and there's a deeper problem such as RFI noise causing the issue or a vacuum leak that is confusing things. I'll give the ". 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! We do that but most places don't. RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the I set the AFR at 13.5 and all is good now. We're never going to fill up your email box with nonsense. It turns out that some of the Snipers are shipping with the minus 40-degree setting drastically lower, as shown in the following image. The idle will not return to the set value.The second issue is the same as the first but the motor will stall out. Why is this? I pulled over and turned the car off and then back on. It does this with the engine off. 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. 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. That initial rev is going to be determined by your IAC Park Position. 34K views 1 year ago Holley Sniper How to Set The IAC Idle air Control in 5 minutes or less. It is made by one of the biggest names in fuel filters and sold under the Parts Master label so it is quality and great price in one. I installed my Sniper and the engine fired up great. We'll also be contacting you for future purchases now that I've discovered you! As soon as I got the new one installed and wiredit fired right up and did everything it was suppose to do with no issues. Relatively new Sniper EFI install on a '69 Mustang 302. What can I do? Price Point: $$, Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. Your mechanical advance will naturally change the timing a bit but it should be fairly close. 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. Or, at least, it should. Now it registers zero and I have good idle but it will not register until it hits 60 and up. Yes, having an accurate TPS is very important at idle. We've already tried adjusting the Acceleration Enrichment chart in all ways, going up and down, RoC Blanking, everything, it has no effect. Have you confirmed your fuel pressure at idle is 60 PSI? Note that sometimes you can get into a back-and-forth situation. These aren't generic newsletters either but instead personalized emails. I can get it to fire up on the (Plus they it just looks way cool in your engine compartment!) These are "transitional" cells, and you really have to make the effort to learn in these areas of the map. THANK YOU for the "First--Check Your Idle Speed Curve Setting!" We offer some tips to help with that. I was shocked to see it at 95lbs!! I'm new to EFI and have no idea what to try next. % = 49 Cycle the ignition as instructed by the handheld and then navigate to the distributor setup screen. 680-700.I can't find any reason other than it looses where it is in the firmware with Copyright 2022 Holley Performance Products, Inc. All right reserved. 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. This will tell us if the ECU thinks that it is in control of setting the idle or if it thinks that you are driving the engine speed with the pedal. I can tell you that when things aren't working the way you wanted them to work that nothing beats knowing for-sure that you don't have a fuel supply problem. If you are using your Sniper EFI System to control timing, navigate to Tuning > Advanced > Advanced Idle > Idle Spark and ensure that the Idle Spark Enabled is set to Disabled. idle counts from 0. Always had to set idle above 950. 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. Should I just disable idle timing control? I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. I think you'll be all set! Ive also used another snap on light to confirm. The problem was RF interferance . 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. Take it a step at a time. I am Japanese who attached Sniper EFI. I know this is old, but I bought and installed a Sniper kit in 9/18. Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. Check fuel pressure too (. To keep it running in gear, I have to bump the neutral idle up just over 1000 RPM. When I covered the IAC with my finger, the RPM dropped so low it stalled. A good example of why it's so important to run a good pre filter in the fuel line. To get it to idle the tps is at 2-3-4% even with linkage disconnected and a return spring installed. I've read that a spacer with 4 individual holes will solve this, but after I installed the progressive linkage the noise went away!! 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. normal city driving, I no longer have other problems I had with the original The Street/Strip and race cam setups tend to be too rich initially. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds The noise changes sound with the throttle position. 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). Target AFR at idle is 13.8%. Then, the next time I cranked it, the idle went high and won't come down!" I installed Holley Sniper on three other Mavericks here in Brazil and the problem also exists.I did not make any changes to the parameters, only on Target AFR and the correction on the Idle Speed Curve chart. My problem is low idle. 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! 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. Yes its at 95lbs, needless to say he promised a new regulator would be in the Also ensure the TPS Position returns to zero at idle, & the IAC Hold Position isn't setup too high. It could be, but that seems unlikely.Instead, you need to look at the basics. Those don't impact the way the engine runs and can cause the whistle sound you describe. Then why don't you Get On The List for Emails Straight From Our Pro? I have quadruple checked my wiring and am certain it's correct. This only happens when coming to a stop and the idle is ramping down to the set idle RPM. I have driven it a few times maybe 100 miles or so. IAC Pos.% = 0 There's nothing wrong with manual tuning, but at this point that is just compensating for an inadequate fuel map. My issue is that the TP% will not reset with key cycle and its idleing at 9% TP. And all too often we don't take that extra step of using a piston stop to ensure that the timing pointer is on zero when the engine is truly and exactly at top dead center. If you go too low then it may stumble or even stall when coming off of throttle. I'd suggest that you assume everything the previous owner did was wrong until you can prove that it was done correctly. Price Point: $$$. If you go too high then the motor will not return to your target idle when you come off the throttle. This page was generated at 12:25 AM. Let me start with the engine not starting until you press the throttle. It may take a few tries. Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to 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. 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. Then it will ramp down to 1200 but will not return to idle. If you find that adding 5-10 degrees of advance helps then it's time to do reconfirm TDC. Otherwise, if removing the air cleaner eliminates the whistle then try to use a thicker gasket or try lightly greasing the gasket. 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. But as you see from the recent revision I did above you seem to be having a fixable issue. Several good bits here. My Sniper is 99% great! IAC is good 0-5% most of the time. This page was generated at 12:25 AM. There is no sense proceeding until your TPS is at zero at key-on. nothing stays steady. 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. 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. 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. Hey Chris! If not then I think you are going to find that this will solve much of your problem. How can I adjust the startup speed down to about 1400 RPM? I never had a problem with this. 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. Simply use your handheld controller and go to the Tuning > Advanced > Advanced Idle > Idle Speed screen and click on the Idle Speed Curve function. 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. New install, when in setup wizard TPS says 90 percent and I checked the linkage and butterflies. 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. It's pretty hard to get the header tubes glowing at idle with a lean AFR. Next, reach down into the secondaries and push the butterflies closed. You could install the Holley Dual-Sync Distributor and let the Sniper control your timing. One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. I'm Having trouble with the Sniper on high Idle. The Sniper even has a feature that allows it to use the idle timing to control the idle speed. to. Check the Distributor Tach Connection to the EFI. Super helpful and knowledgeable. Could the IAC be broken/malfunctioning? 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. Engine warms up to 195 degrees and stays. Thank you for this guide on setting IAC. Repeat until that stumble goes away, and then try a bit more throttle. My IAC was constantly at 100% at idle. That is not something I'd ignore. So this is my issue ( I did just email Holly). Idle was back to normal but iac was at 0. 3 different fuel pumps. In that case, and if you have an EGR valve, I might be suspicious of something going on there. Be aware that there is a spring behind there and a diaphragm that you don't want to tear. Add To Cart. I have never seen issue when CTS is below 120 degrees. When I shut it off then start it Since it is unlikely that anything else changed it is most likely the IAC is problematic or the butterflies are not shut all the way. Ive tried setting the prime setting above 150 but it wont take, it always goes back to 150. If i adjust the throttle plate screw in to bring IAC in to proper range say around 7 the engine is running around 2000 rpm. I am having an issue with the IAC on the Sniper. Idle was around 1000 mark and iac 0. 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. 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. shut truck off. Cracked casing from a side cover screw being installed crossed threaded. Ensure all your sensors are displaying proper values. One of the signs of a vehicle with a rough idle is a faulty Idle Air Control (IAC) Motor. So, if pressing the throttle is making it start, it's because you're flooded.Which is consistent with your rich idle condition comment, right? It only lowers to 2-6% when I take my foot off the gas. So try changing your IAC hold value slightly:Tuning : Advanced : Adv. is the fuel pressure. I'm running a 408 sbc. 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. Try it! I cut and heat-shrink wrapped the 5V wire and then ran both the signal and ground wires all the way back to the transmission controller. Get that thing installed and you're going to know a whole lot more about what's going on. I presume your idle speed table doesn't increase at 200 degrees? What could be the cause? There are six different acceleration enrichment tables that you can tweak and that may be the way to go. But another thing to consider is adjusting your target A/F ratio. I have one customer who is having some similar issues and his AFR is down at 9.6:1 when it won't start. 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!) This is extremely unreliable afrer warm. It sounds like you need a bit more of a fuel squirt on acceleration, Brett. When I drive with warm engine the IAC is at 30% when pushing gas, but shouldn't it be at 0%? If the issue persists, you may need to replace the IAC. I think that your Sniper system is working fine but would definitely check ouf the fuel pump. Were the additional load a simple step function it would be challenge enough for the ECU to gracefully increase the engine speed without overshooting. With the engine still idling high park, set the brake, open the hood, and remove the air cleaner. It reads 0 at idle and when I accelerate it goes up to 30 and makes a loud sucking sound that seems to be holding the car back. I'm so glad you found this helpful--that makes my day!Don't get too concerned about the specific learn percentage. I have been reading these posts and have learned a lot.
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