These are "transitional" cells, and you really have to make the effort to learn in these areas of the map. (Plus they it just looks way cool in your engine compartment!) If I adjust idle screw out to get the tps to zero or even 1% the engine will not idle. Sorry for all the questions, new to the efi world. I have adjusted many settings and eventually mess it up and go back to the original map. 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. If the TPS is 1% or below then the air is coming from somewhere else. Seems to behave more better now. I am Japanese who attached Sniper EFI. Thank you for any advice. Let's start by not assuming anything. (If you do this you will need to reset the -40 degree setting mentioned at the top of this article. That initial rev is going to be determined by your IAC Park Position. 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. It has a lightweight centrifugal spring kit installed so I reach total timing around 2500 rpm. Drives just fine but won't stay running unless I keep my foot on the gas. https://www.gmperformancemotor.com/parts/19210007.html, http://forums.holley.com/showthread.3128#post83128, If this is your first visit, be sure to You'll have to go back and forth a couple of times to get it just right. The distributor was loose. Does that make sense to you? I have not heard of this. IAC looks good once it finally s fires. Clearly, something is changing. installing and cruising down the highway 70 mph I just wonder if all I have to do Thanks! Thanks for your very detailed question! port that goes right on the inlet of your Sniper and makes installation a breeze.If your fuel pressure is solid at about 60 PSI then you should start looking at Save Share. Copyright 2022 Holley Performance Products, Inc. All right reserved. To start viewing messages, select the forum that you want to visit from the selection below. 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. Your mechanical advance will naturally change the timing a bit but it should be fairly close. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. After speaking with Holley Tech Support and Tech Support from where I purchased the systemthey decided to replace it. 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. The answer will divide the possible sources of additional air into two, greatly simplifying the problem.If the IAC number has not increased, then review the article above regarding high idle from a vacuum leak or high idle from sticking linkage. 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. The next time it happens is the perfect opportunity to find the problem. And thanks again for taking your time to answer these questions. 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! That So the issue Im having is low idle. After only running for about 15 minutes or so the system starts to fail stalling the motor. A few, however, get tangled up getting the idle control working just the way they want. An undersized or partially plugged fuel filter is a classic EFI installation mistake. One of them might be faulty. Consider adding fuel in the AE vs TPS and/or AE vs MAP ROC tables in the area where the stumble is occuring.Since this is happening at such low TPS levels it is possible that your engine would prefer a lower (richer) target AFR number at idle. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds Anyway I have a 327 sbc in a 1987 Monte SS with a T5 5 speed and 3:73 posi rear. The learn function will offset the base fuel table until the closed-loop compensation only requires minimal changes. Thanks again Chris, your help has been invaluable.If anyone is considering going EFI, Chris is the man to chat with. Keep in mind that at 60 miles the While confirming, in the handheld ensure that the Reference Angle is set to 57.5 and that the Inductive Delay is set to 100. That is the first thing you must find. Turning it off and back on would reset it, and then it would work as advertised for a while. I.e. )Then look a the datalog and find out what TPS ROC and MAP ROC is most likely to cause the problem. Holley EFI Electronic Fuel Pressure Gauge, article on choosing between Sniper and Terminator X throttle body solutions. It's hard to know what the previous owner did right versus wrong. close to idle with the IAC between 2% & 12%. So check that timing and I think that you're going to find you need a good bit of advance. There's still a very small amount of airflow that squeezes past a closed IAC valve; it's that venturi like sound you're hearing. Any suggestions? If it creates an issue (not normally the case) then you'll know. Handheld shows plenty of fuel so I dought it's an issue there. first attempt but as it tries to idle down to the target RPMsit can never even Camshaft is M-6250-B303 .480 lift intake & exhaust, duration at .050 is 224 degrees for intake & exhaust. Jump on board now! In the time it takes to add your email address you can be at the top of the heap for getting the latest information from our authority. 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've helped folks work through a number of challenges with their Sniper EFI System installations. I think that the more important point is that Holley kept sending him units until everything was working. However, I have what I will call a whistle at a throttle position on 35 - 50. Commanding the engine to automatically increase speed when switching into drive is a little scary to me though. If I put the truck in park it comes down to idle. So this is my issue ( I did just email Holly). Hello We are using Target AFR of 9.0: 1, Fuel Base approximately 40% higher. Without it you are working in the dark. So you installed your Holley Sniper. 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. (Do this while you are cranking.) Let After pumping the pedal a few times at different times it dropped to zero and started to work. I also noted that after some time, I could change those values as I saw fit. Genuine Walbro fuel pumps are virtually bullet-proof. !I called Holley today, and before I could even described the symptoms the Running the vacuum advance and of course I time it disconnected. Second--even in the HP and Dominator systems where a fuel pressure sensor can be dalogged and displayed, the fuel pressure is not fed back into the algorithm. I'll give the ". Suddenly, the engine accelerates alone, hears a great deal of air being sucked in, I recently bought the car with the EFI system on it. The Super Sniper will allow you to monifor fuel pressure if you add an electronic sender but this is not an option with the standard Sniper. 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. 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. started up the engine. You are looking in the right area but I would probably not change the ROC blanking. Eventually the IAC will drop back to zero, I'll readjust it to 850 RPM & 2-9%, and then watch it steadily climb again. Strangely, what I've seen is that it idles too lean as the injectors are effectively shut off.Thanks again for the follow-up and glad to hear that everything is working well now. I've been trying to correct that 1% small issue/annoyance. Another suggestion is to add an extra turn to the spring built into the linkage to increase the closing force on the throttle shaft. What is it supppse to be at idle and while driving under heavy acceleration? 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 Cycle the ignition as instructed by the handheld and then navigate to the distributor setup screen. hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I The idle will not return to the set value.The second issue is the same as the first but the motor will stall out. mail today. A good example of why it's so important to run a good pre filter in the fuel line. Start by doing the fastest start you can that doesn't bog. is the fuel pressure. 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. School's out for spring break this week though so I'm covering for employees on vacation. 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. You're going to have to get this fixed or it's going to cause even more problems than the high idle. But if you can datalog the bog you can know much more precisely what is happening. 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. Of the two options, I generally recommend the self-learn. We're having trouble with a Ford Maverick 302 V8, using ethanol. It wont fire up. Target AFR, A / F = 13.5 I am having an issue with the IAC on the Sniper. There are two ways to address this--you can let the system learn or you can manually adjust the acceleration enrichment. engine works beautiful, the car runs a lot, but suddenly, the engine does that. Im not sure what its doing, have messed with after start fuel, fuel at cranking. Last night I tried setting the IAC and had the same problems after it's warmed up. Thank you for this guide on setting IAC. 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!) Have a look--I think this is going to allow you to fix your idle problem. When I first told him to check for leaks he looked back there and said "all good". Any suggestions would be appreciated. Sniper EFI offers superior throttle response and wide-open throttle power. After this whole process, the car normally rotates without a very abrupt pedal. Hi Chris I didn't get any traction on Holley.com 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. Any idea's? Start engine let it warm up to 160, learn mode is learning. Remove the tape from the IAC breather hole and restart the engine. When running it will only stay in closed loop and learn at idle. 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. The team at Holley has designed the perfect solution for your problems. Always had to set idle above 950. It runs perfectly fine other wise. I'm new to the efi thing and any help would be seriously appreciated. I am new to the EFI scene but want to learn. This can cause the engine to run rough and may even lead to engine damage. It sounds a little different from mine, since it commands a 1300 or so increase intermittently. It's the same one that Holley puts in their Sniper Master Kits and I've never heard anyone with anything but good things to say about it. I have one customer who is having some similar issues and his AFR is down at 9.6:1 when it won't start. Thanks again. )So before I hook up another gauge to see if the Auto Meter is bad (assuming I can find a 0-100 test gauge in my shop). This software is going to allow you to open both the configuration file and the datalogs that you create, overlay them and you can get a much better idea of what is happening. :-). 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. :-). Its timed to 36 degrees. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. Do you have a PCV on the engine? Hi Chris thanks in advance for any tips. other things that might cause the idle to faulter, but this is a good start. 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. Inj. Very annoying ended up being simple my rear plates would stay open constantly it was driving me nuts I'd let off the pedal idle at 1300 blip the throttle a few times finally come back to 850. Bolt on 4150 Flange Carburetor Replacement. I also raised idle at Park a bit with the idle screw. If you do find you have RFI issues then I've written an . I think that your Sniper system is working fine but would definitely check ouf the fuel pump. Idle Tuning is a very important part of tuning any EFI system, especially our self-learning units like Sniper or Terminator X EFI. 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. By the way, this is a new installation on a 69 Camaro, stock 350, dual sync, etc. If you find that adding 5-10 degrees of advance helps then it's time to do reconfirm TDC. I drove it a bunch more yesterday afternoon/evening and the same thing happened several times. That's what you're seeing. About two minutes after I get it set at 850 & 5%, it has progressed to 100%. Adding a wrap to the return spring on the shaft is one alternative to solving this. Holley Sniper EFI Troubleshooting Mudford Garage 8.6K subscribers 38K views 3 years ago My Bronco with Holley Sniper EFI was running poorly. I have a Holley Sniper EFI with HyperSpark ignition. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. Even though the Sniper's fuel map is programmed to provide the correct amount of fuel via injectors spraying at 60 PSI, if the pressure is jacked up to 90 PSI the wideband sees that you are rich and faster than you can even detect it audibly lowers the duty cycle to inject the correct amount of fuel. Let me start with the engine not starting until you press the throttle. This is actually more troubling than the sound you originally described. It is how the engineers allow you to clear a flood condition when you detect it. The headache is the Acceleration Enrichment. back upthe RPMs shoot up to anywhere between 1500 and 2000 and they will not get Your suggestion to remove the PCV valve is just for diagnosis purposes, right? Intake has been on and off 3 times no change. May God's grace bless you in the Lord Jesus Christ. 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. It's all part of the adventure! This is normally used as an A/C idle-up circuit. Should I just disable idle timing control? 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. 1. Price Point: $$, Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. ChrisI finally got everything resolved. 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. If I cruise down the road at lets say 60 mph and lay into it, she will take off and go. When I put it in gear, it drops so low that it will stall if I don't add throttle. So if you are trying to achieve a stoichiometric mixture in ethanol (which is achieved at an AFR of 9.0:1) then you should continue to target 14.7:1 since that is what will be displayed. I am at the point where I almost insist that every Sniper EFI System owner purchase one of these. I would only play with this if you are finding that the other adjustments I suggested aren't working. It won't take much! If it is already adding fuel, it may be worth expanding this into the area where the tip-in is occuring (and where there is no learning occuring. If the screen shows iac at 0 and you block the hole to find it open what does that mean? I have been able to get it pretty Thanks so much for reading! The only way to do this is by installing a mechanical fuel pressure gauge. I am having an idle issue (other than that is absolutely perfect). 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 did change the -40 thing also. The on board fuel pressure regulator in the Sniper throttle body has a small filter clipped over one end . Full product line and accessories at excellent pricing. 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 put it in neutral and the idle RPM had increased to 2100-2200. But nothing beats a good solid gut-check I'm happy to walk you through what is required. With everything else being right and since you can make it start by adding fuel it seems like you must have some sort of fuel pressure issue. The Sniper EFI remote IAC (Idle Air Control) and plug is designed to gain installation clearance on some Sniper EFI 2x4 installations. 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.