Once we recognize that, the next step is to narrow down all possible sources of additional air until we discover the cause.Start by keeping an eye on your IAC number. It runs perfectly fine other wise. If idle drops below 800 it wont come back itll chug around 300 rpm for a few seconds then die. I did check for the lightning under the hood but all was well. Technically it is a warranty-voiding maneuver so proceed at your own risk. Even 50 RPM can make a difference in how much impact the transition to Drive has on the idling engine's ability to stay at a fixed RPM.I would not recommend it in this situation but anytime a "kick" in idle speed is desired that is easily done by setting the kick value in Tuning > Advanced > Adv. When I see that your TPS is 1%, that tells me that you may have an RFI problem. Drive great and idles perfect at stop signs. First--besides the fact that it's not represented on the display, it is not even a parameter that you can datalog. Just getting it to act right at startup is a struggle.
Sniper EFI Initial Startup and Troubleshooting Staff Writer 01/20/2020 (Note: in the original version of this post we had a section about checking the idle speed curve setting. One of the signs of a vehicle with a rough idle is a faulty Idle Air Control (IAC) Motor. Am I missing something. First thing I would check A common issue we see is a result of poor fuel pump grounding running a eyelet from the pump ground to a rusty or painted surface. Perfectif you have the original synchronous linkage. Enjoy! The fuel pressure regulator in the Sniper is fairly simple and not prone to failure, as far as I know. Once you so this, and after you have your CAN-to-USB harness attached to your laptop with the Sniper software, you can see precisely the cells where the system is operating when the bog occurs. When I shut it off then start it You can find those settings here: Handheld: Tuning > Advanced > Advanced Idle > Rampdown, Software: Idle > IAC Settings > IAC Ramp Down. The whole topic of using the Sniper TPS for transmission control is one deserving of it's own article but I'll try to summarize a bit here. The engine has 14: 1 compression ratio, we can not use gasoline. But I wanted to go ahead and answer this so that it would make sense to someone who might not go that route.I think the first thing I'd do is try another pressure gauge. If no air is passing (and the idle doesn't drop) then your IAC is working. I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. 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. Also ensure the TPS Position returns to zero at idle, & the IAC Hold Position isn't setup too high. These will fix the noise but if the performance is suffering then likely you won't see any difference since it is not likely to be related to this sound. Thank you in advance for your help and providing us rookies with your My Sniper is 99% great! Your suggestion to remove the PCV valve is just for diagnosis purposes, right? I do know that the reference angle is 57.5, the inductive delay says 100.0. Just thought I'd ask as there isn't a lot of info out there. I have quadruple checked my wiring and am certain it's correct. Running a bbc with coil - my timing is perfect. It's not necessary to drive it that way. When I am coming to a stop, the rpms will hang at 1200-1500 rpms. 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 have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. % = 49 I installed another return spring for the rear plates problem solved instantly. So the issue Im having is low idle. One thing you need to sync the timing and set the inductive delay. 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. And the rather cavalier "Absolutely!" Reply Quote. That initial rev is going to be determined by your IAC Park Position. Idle : IAC Rampdown : IAC hold positionChange this by maybe 2% in either direction. You should get a light spray evenly distributed in all four barrels. If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. The distributor was loose. Last night I tried setting the IAC and had the same problems after it's warmed up. If this is the case then I would look particularly close at the IAC hold position and IAC ramp start.Let us know what you find and what works for you! Let me start with the engine not starting until you press the throttle. If I go any more it will ping. check, I guess after reading everyone saying how great the system is after Thanks for all your help Chris! Give us a hand! I have a set of 8.8 Accel Rfi suppression wires on it. I can drive it a bit but pops through the throttle body when pulling out from a stop (4 speed) and sometimes in the exhaust out on the road. no timing control. A simple remove & clean will remedy this . *Possible delays due to Covid-19 click for more information. Sorta similar to a carb having the idle mixture set incorrectly (rich) or the idle speed too low. Thanks! When I put it in park the idle RPM was 2100-2200 each time.
Solving Holley Sniper High Idle Issues - EFISystemPro.com But he kept having problems so eventually he did a complete check and then he found the problem. The fact that it ran so (at times) with 90+ PSI fuel pressure is a testimony to the Holley's closed-loop technology. Its just at low speeds, not sure if its loading up or leaning out. The IAC going to 30 is normal. This page was generated at 12:25 AM. During cruising at 30 miles and release the gas pedal the engine revs at aproximaly 1500 RPM and it won't drop. Thank you chris for for getting back to me on this matter.I'm using russell hi pressure gas line to feed the gas up to the sniper and using the stock steel gas line that use to be the feed line for the carb to return the gas to the tank. Why is this? As you see above, the Sniper is going to dump in a maximum amount of fuel at zero TPS, begins to remove acceleration enrichment at 60 percent TPS, and then removes all acceleration enrichment correction at 100% TPS. We are using Target AFR of 9.0: 1, Fuel Base approximately 40% higher. These are "transitional" cells, and you really have to make the effort to learn in these areas of the map. Capability Range: Professional Yes, let me know how that setup process works. Ive had an idle at neutral as high as 2400 rpm. I called support line he said he would have to look into it and call back. As inconvenient as it might seem, I'd recommend keeping a timing light handy and checking your timing during the high idle condition and then again after restarting. The RPM would increase for no reason. When I put it in gear, it drops so low that it will stall if I don't add throttle. I go into much more detail about that in this article on startup tuning. Fought a high idle issue until I changed your idle speed curve fix along with dropping the IAC hold to 10%. My car will not idle right until it gets to around 130 -140 degrees. However I do have a couple of issues I hope you can help me resolve. This may require shortening or lengthening a rod. Bolt on 4150 Flange Carburetor Replacement. Any suggestions would be appreciated. Those don't impact the way the engine runs and can cause the whistle sound you describe.
Sniper EFI Problems - Holley Performance Products Forums You could install the Holley Dual-Sync Distributor and let the Sniper control your timing. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. Overview. If you feel you have no other choice but to run a Sniper and stand-alone controller then you can give this a try. Do I need to try taping up the IAC port and setting the idle off the idle screw? During after-start idle, the idle will jump up to about 70% if the engine is cold, stay there about 4 seconds and then ramp down to the target idle speed for the current engine temperature. 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. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. To keep it running in gear, I have to bump the neutral idle up just over 1000 RPM. We do that but most places don't. May God's grace bless you in the Lord Jesus Christ. I'm Having trouble with the Sniper on high Idle. 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. If you set the RPM above idle to start ramp too high, then it may not ever get down to the RPM above idle to re-enable. It will need to see it again and again. Its timed to 36 degrees. I put it in neutral and the idle RPM had increased to 2100-2200. The window you saw in the image above pops up. 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. It has gotten a little better after I drove it for three hours today.I want to save the Kik because if I get this working good then I would like to add A C and use the kick for it.Motor is Mopar 360 with mild cam and automatic. 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. AGAIN This is Intermittent meaning on a recent trip I stopped 3 times and issued occurred once. That is the only way to fly. 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. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. 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 get into the practice of hearing all three of these sounds you will know if you have a problem even before you turn the key to crank. No air should be able to pass. Throttle body mounted ECU - no extra boxes to mount. I also noted that after some time, I could change those values as I saw fit. I'm thinking it could be the fuel pressure--- since I have a new Spectra EFI tank and there's been some reports of the interior coating coming off and gumming up the pump however the sniper display DOES NOT show fuel pressure.the Sniper DOES measure fuel pressure on its own - i've confirmed that with holley techs as they told me to purchase the fuel pressure gauge that can just hook up to the 1 wire gauge harness from the Sniper. I think you will find that it will learn its way through this. That is the IAC hold position. Therefore The iac will always be at 10% now, correct? Once engine is warmed up been driving for awhile. 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. It's not that they (or any other manufacturer) is 100% perfect. 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!) Don't know if I should put this in a separate post. Thank you. Supports up to 650hp with Four 100 Lb/Hr Injectors! Throttle Tip-In tuning can be a bit of a challenge but I'm confident you can get this resolved, Mike.Let me start by saying that unless you've really done a lot of driving on the system in some useful learning situations then I would set this issue aside and not even think about it. Interesting question. I straightened that out, got it running and that's where it goes downhill. Hot start it most of the time wont start unless I give it a little throttle. The tps has slotted holes, can you adjust it to get to zero? However, I did have another fellow who contacted me that claims he went through three units before he could get one that would talk between the ECU and the Monitor. Give it a watch: https://youtu.be/7SO7-tZn6iw. 63 bomb But if I take off from a stop and go to 1/4 or 1/2 throttle its fine and takes off like a banshee. 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. 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. I would start by removing the progressive linkage. No timing control, coil negative ignition type. 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. 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 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. Definitely would have went with you guys. 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 have replaced the IAC motor and the problem remains. I' m going to put the 3rd new pump this coming friday. You will need to change the -40 degree idle speed setting again but I recommend not touching anything else. That is the first thing you must find. I recently had IAC issues identical to what you describe. (It should be at or near 60 PSI at idle. Im thinking a faulty TPS. Chris, I recently installed my Sniper and have an intermittent idle problem. To be honest, you sound like an ideal candidate for Sniper ECU ignition timing control. 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. :-) Just don't let the parts go flying. I think I figured some of my problems outI'll try to explain. Your comment doesn't imply any sort of problem that would make me give up on idle timing control. You'll have to go back and forth a couple of times to get it just right. is jumping all over the place when you experience this condition, it does not The broad consensus has been that the Sniper is an amazingly straight-forward install and starts and tunes as expected. No problems with either cold or hot starts. In that case, and if you have an EGR valve, I might be suspicious of something going on there. Drives just fine but won't stay running unless I keep my foot on the gas. So I have been doing the slow take offs and thinking that it would learn its way out. That is certainly not normal! First, recognize that the IAC and the TPS are not inter-related in any way. Start by doing the fastest start you can that doesn't bog. Ensure all your sensors are displaying proper values. 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 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. When the system is up and running the fuel pressure regulator inside the Sniper is making a rattling sound like a shaking a paint can. 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. I'm going to jump out on a limb here and say you either don't have adequate fuel flow or pressure. To finish, I rather tightly twisted the TPS signal and ground wires all the way from the controller to the Sniper TPS and very carefully routed them away from sources of RFI. Yes, it will talk to you--but not with words. So try changing your IAC hold value slightly:Tuning : Advanced : Adv. My car will now start when its cold, but after about 30 seconds the idle drops down and begins to run like crap. It is probably that your RPM above the maximum point at which ramp-down can occur. Rpm with 4-8 iac but it still shows red and shuts off randomly at idle and it won't even drive 2 miles without shutting off. EFI Systems based on Holley's world-class Dominator and HP ECU's. 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. If so remove it. This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. :-). I appreciate the help youve given to everyone as it continually helps me! Car has run perfect every time and has never hesitated or stalled since. You have to remove all hoses in order to debug the problem.
Sniper EFI - Holley 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. This minimizes installation time and packages really well on a diverse group of engine applications. It didnt do this with the carb on it. One of them might be faulty. That changes almost instantly as the engine revs.Since the learning algorithm requires some time exposure to a certain condition to make larger changes, that half-second makes only the smallest impact. As I said I didn't buy from you so you don't owe me anything. 1. And the only way to be positive about that is with a gauge.Unfortunately, the Sniper does not provide an input for an electronic sender so the next best thing is an analog gauge. If the TPS is 1% or below then the air is coming from somewhere else. If the IAC number is increased during this high idle, review the points about high idle from tuning issues. This can cause the engine to run rough and may even lead to engine damage. Find a lower price anywhere and we'll beat it by 5%! But you've got to find where air is getting into your engine.The reason it's going up as high as 2400 RPM is because once you press the throttle beyond 1% the IAC opens to the park position. Again, I would lean on that solution to let the vehicle drive/learn before you try to "fix" anything. If I put the truck in neutral the TPMS will raise all the way up over 2000. The on board fuel pressure regulator in the Sniper throttle body has a small filter clipped over one end . Hi Chris thanks in advance for any tips. I.e. The "PC Text" indicates what will be shown on the PC/Laptop data monitor or data logger. Capability Range: Moderate It is how the engineers allow you to clear a flood condition when you detect it. I notice at 2-3% tps the iac is 18-25% and it stumbles, when the iac gets to my hold position of 30 it stops. Or, at least, it should. All of the wiring exits below the rear fuel injector cover, for a completely stealth installation. But I am having troubles.When stepping on the accelerator slightly with idling, it will be 2000 RPM all the time. Thank you so much for your follow-up. I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. Thanks again. To figure this out it's going to be important to gather a bit more data. Idle was back to normal but iac was at 0. Next, clean the IAC and all related parts with brake cleaner. Thanks for your very detailed question! I was looking at a data log from my truck earlier this week and noted that at idle my IAC was zero. If the engine will after the 4 seconds that the IAC kick drops off then it's not really going to help.At any rate, it costs you nothing to advance the ignition and see if that doesn't improve the idle, right? I will turn it up some. 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%. This happens no matter how much I adjust the idle screw. And yes, monitoring the fuel pressure is the right answer. Plus, you can email that file to me and I can be of more help. If you look down and your TPS is 2% then either your throttle is stuck slightly open (which itself will cause the idle-up) or RFI riding on the TPS signal has caused the ECU to see the throttle as open and, as a result, open the IAC to the hold position. Also its extremely rich at idle. Usually it wont stay on 0% very long and soon changes to another number like 1 or 2%. I can adjust at 160deg, but my fans turn on at 180deg. Have a look--I think this is going to allow you to fix your idle problem. 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.
Holley Sniper EFI :-). 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! shut truck off. These aren't generic newsletters either but instead personalized emails. Hopefully replacing the pump again will resolve both issuesWhoa. 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. This car has never idled under 900 without stalling with 3 carbs and does the same thing with sniper edit. See these. Cycling the power to the Sniper EFI would cure the problem, but not prevent it from coming back. This page was generated at 12:26 AM. 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. MAP Sensor. One additional wrap on the secondary coiled shaft spring is all that's necessary. The Tech Tips and discussions are also great! We have never had that problem with any of the units that we have shipped. (Don't drive and watch--get a helper!) Super helpful and knowledgeable. After 50 on the throttle position I'm not sure if the whistle goes away or you just can't here it anymore. It appears that I could now use the dongle and a laptop to custom tune for idle issues if needed. All times are GMT-6. Then it will ramp down to 1200 but will not return to idle. Shut off the engine, ensure power to the Sniper is switched off. The engine ran so good, I would have never suspected the Fuel Pressure to be an P.S. I have been able to get it pretty 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. 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. around 45 mph it bogs down, catches itself, bogs, catches, bogs and catches. Holley Sniper IAC Surging???? 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 very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. When I put it in gear, it drops so low that it will stall if I don't add throttle. If you can track specific engine coolant temperatures where the engine stumbles and dies that would be a good place to start. What I would recommend is getting somewhere that you can spend a significant amount of time doing starts. Please check your process again and see if you can see very specifically what is not working correctly. it will jerk and rpm will go up and down and AFR will be around 20 : 1 or more or less. Since your target is probably more like 700, and since 2400 is way over 1700 RPM, it's going to leave the IAC in the park position.Buckle down and find how air is getting into your engine. At any rate, once the setting was moved up, the RPM jumped right to the target RPM and was solved. first attempt but as it tries to idle down to the target RPMsit can never even A couple of those and you should feel it getting better. ChrisI finally got everything resolved. 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. What an amazing site you have here. itself out and hold idleeventually stalling. Ok, so there are a couple peculiar things going on here. 2. Thanks. 3 different fuel pumps. First, recognize that the amount below your target where you set the hard idle will be different on different engines. The first 250-300 miles were amazing as the Sniper EFI worked flawlessly. Suddenly, the engine accelerates alone, hears a great deal of air being sucked in, If you hit the gas it pops & backfires through the throttle body. That will at least tell you something. Is there away to program the ecu to compensate for this at start up. Thanks. Ensure there isn't a vacuum leak causing the IAC Position to drop to 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. Contact whomever sold you your system or Holley directly. If I cruise down the road at lets say 60 mph and lay into it, she will take off and go. Lubricate the linkage so there isn't as much native resistance. Going in the direction you did (higher) is going to reduce the acceleration fueling that the engine sees. If that happens then follow my 10-step process shown above. I received from the controller manufacturer greatly understates (at best) the repeated failures of others I know personally who have tried and failed. Was perfect idle iac reading 3. If not then I think you are going to find that this will solve much of your problem. By the way, this is a new installation on a 69 Camaro, stock 350, dual sync, etc. Thanks again for your insights! For someone in your position, it will become an indispensable tool in your tool box. Second, Holley just released over the weekend a video on how to implement a flex fuel sensor on their HP and Dominator ECU's. ps. If it is then something is commanding the ECU to open the IAC. EFI System Pro had everything I needed for my EFI upgrade. The fuel pump is mounted under rocker panel as low as possible and far away from any heat. 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. This is extremely unreliable afrer warm. Chris thank you for the info. 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. I am right back to where I started. 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. This may sound crazy but I'm going to jump out on a limb here and say you don't have an idle issue--you have a timing issue.
Holley Motor Life The Sniper EFI remote IAC (Idle Air Control) and plug is designed to gain installation clearance on some Sniper EFI 2x4 installations.
Holley - 543-105 EFI Idle Air Control Motor , Black - amazon.com