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. On EFI systems such as Holley's Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. Short drives is fine then it'll Cracked casing from a side cover screw being installed crossed threaded. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. I have quadruple checked my wiring and am certain it's correct. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. When this occurs, I sometimes can shut it down and it will return to the correct settiings. I' m going to put the 3 rd new pump this coming friday. I then saw you guys have an awesome little gauge that can hookup inline to the snipers existing fuel feed?? By the time I was near home, the idle in Park was 1050, IAC 0. I think you'll be all set! I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. When this happens, it is impossible to convince the Sniper ECU to allow the RPM to drop below a set RPM--regardless of what the target idle speed setting is. 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. Turn the idle speed screw on the primaries in about 2-3 turns after it makes contact with the linkage and starts opening the primary throttle blades. This value is itself enough to raise the idle a bit. The first place my eyes go when there is any issue with the idle is to the TPS value. Capability Range: Advanced When I start the motor I have to push on the accelerator pedal for the motor to start. When you set the Static Timing to 15, what did you read with the timing light? If I rev the engine a couple times in neutral it will finally return to idle & usually will not do it again for the rest of my trip. You might have a bad IAC, but you can also have a bad vacuum pod on the transmission. Idle was back to normal but iac was at 0. Also, I was seriously rich at idleso rich it hurt your eyes. I installed another return spring for the rear plates problem solved instantly. issue. You mentioned going from 13.5 to 14.2 but you'd want to go in the other direction--maybe to 13.2. While this video is not meant for the Sniper EFI user it does provide a great overview of how your ethanol tuning adjustments must be made not only to the base fuel map but to the other configuration settings. Do please let us know what you find out! Ive had an idle at neutral as high as 2400 rpm. I appreciate everything you are saying. May God's grace bless you in the Lord Jesus Christ. Try it! Running a bbc with coil - my timing is perfect. Don't know if I should put this in a separate post. After a stall the car will restart but will be in a high idle. I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. This is a mighty big subject for a blog post reply, I should probably start doing some videos on this. (I'm running from a fuel cell on the garage floor 10 feet away with lines in plain sight and do see fuel coming from the return at a decent flow. Thanks again for your insights! Yes it is controlling the timing and I had issues at first and it controlled the idle just fine. IAC looks good once it finally s fires. If the regulator is working correctly and there is no restriction in the return line that should make no difference however.Sorry I didn't see this on the Holley forum. I'm compltely stumped and my wife is certainly upset I'm spending so much time between the garage and the computer for something that should basically run out of the box. Idle when warm was 850-ish and IAC 3-4 just as when I readjusted it the night before. Nothing against Holley's method but I need to keep things simple and I do that by eliminating the effect of the IAC entirely while getting the idle speed adjusted. That is not a huge problem but it just means the IAC has no ability to lower the idle beyond what it is running at that point. Using the handheld, navigate to Tuning > Basic > Basic Idle and ensure your target idle speed is set to the RPM you desire. When I see that your TPS is 1%, that tells me that you may have an RFI problem. Always had to set idle above 950. It might be necessary to insulate or re-route your fuel lines if this can't be solved any other way. 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. Holley will take a look and tell you you have RFI and wish you good luck in finding it. (Do this while you are cranking.) If your TPS has snuck up to 2% then your IAC will be at the hold position, which by default is 30%. In the setup, I set the hot idle for 850. Please check your process again and see if you can see very specifically what is not working correctly. There is a chance that the IAC is open but displaying 0% so start by putting your finger over the IAC opening. Last night I tried setting the IAC and had the same problems after it's warmed up. There are six different acceleration enrichment tables that you can tweak and that may be the way to go. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. Thank you so much for your follow-up. This page was generated at 12:25 AM. Featured Products EFI - Fuel Injection $2.59 - $6,499.95 2179 Products View Parts Sensors Those don't impact the way the engine runs and can cause the whistle sound you describe. the gas it catches itself and runs fine at slower speeds. I also noted that after some time, I could change those values as I saw fit. The Sniper EFI system looks at the closed-loop fuel compensation required to reach your target AFR. Wish I knew about it before I made my purchase. Now, 1% on the TPS isn't a problem, but when it goes to 2% (which is inevitable if you have RFI moving it to 1%) then the IAC is going to go to it's hold position (30% by default) and the engine is going to rev up. One of the best Ive seen so far. It started right up and we did your idle control fix and all is good at idle. 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. When you have the issue you should disconnect all hoses and plug the ports on the Sniper. technical rep said "You ahve high fuel pressure". i would have been happy to answer there. :-). If so remove it. Bolt on 4150 Flange Carburetor Replacement. 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? With the engine still idling high park, set the brake, open the hood, and remove the air cleaner. That way you can get into that part of the table that needs tuning, and you can watch your learn numbers grow. Stupid question, but where do I see if it's entering Learn mode? So you installed your Holley Sniper. 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. The broad consensus has been that the Sniper is an amazingly straight-forward install and starts and tunes as expected. 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. It's going to be really difficult to nail down the problem with the several simultaneous changes that you've made. If idle drops below 800 it wont come back itll chug around 300 rpm for a few seconds then die. EFI Systems based on Holley's world-class Dominator and HP ECU's. (Don't drive and watch--get a helper!) Earl's Mechanical Fuel Pressure GaugeI could use that for a quick troubleshooting for 1/3rd the cost of the Holley one. Others might require 60 RPM. If I cruise down the road at lets say 60 mph and lay into it, she will take off and go. Now it's at 5% on a big cam 440 Mopar. Please let us know how this works out for you! If the vendor from whom you bought the system is coming up blank on ideas then don't hesitate to contact Holley's outstanding tech support department directly at 866-464-6553. other things that might cause the idle to faulter, but this is a good start. I did notice that when I thought I had it set I put it in neutral and the idle RPM had increased to 2100-2200. You can drop it down and you will find it will behave more like you expect. If Add To Cart. Shut off car/restart and it's back to idle at When I turn the key on I can hear it prime, but I don't think im getting enough fuel. But I am having troubles.When stepping on the accelerator slightly with idling, it will be 2000 RPM all the time. 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. Hello The "Gauge Text" is what would be shown on a 2-1/16 gauge or the Avenger handheld display. Going back to what you said. You are aware of the idle-up problem. I installed the Sniper on my 1978 Ford F-100 with a small block With select intake manifolds, the distributor housing and IAC valve on the back of the Sniper EFI throttle body are fighting for the same . Physially manipulating the linkage by hand will generally reveal if you have a sticking linkage that is preventing the TPS from returning from zero. With the vehicle in neutral, adjust the idle screw until the IAC Position reads between 2 and 10%. If either of these is not the case it must be remedied.After you have done this then you might want to involve Holley Tech Support about the TPS, or it may be easier/faster just to visit the local auto parts store and pick up a new TPS and install it. Chris, I recently installed my Sniper and have an intermittent idle problem. I certainly appreciate your frustration (as well as your wife's!) 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. Good afternoon Chris, thanks for taking the time to help all of these folks that didn't purchase from you- myself included!The issue I seem to be having is at idle in both park/neutral and drive. Two things to keep in mind as you do that. I started with right after I first adjusted for 2% IAC and took pics about every 30 seconds over about 2 minutes. What could be the cause? I appreciate the help youve given to everyone as it continually helps me! First, let me congratulate you on your patience in letting the system learn. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? Thanks for the great question! What would cause the idle to faulter like that? In most cases the IAC (Idle Air Control) circuit is the source of the whistle. Give that a go and see if you don't make some progress! 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. :-DStill, I hate to leave someone hanging so I'll try to help. 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. (Note: in the original version of this post we had a section about checking the idle speed curve setting. have the system learn the higher speeds? Of the two options, I generally recommend the self-learn. Well, it sounds to me like your Sniper is doing its best to reduce your idle. When running it will only stay in closed loop and learn at idle. I also raised idle at Park a bit with the idle screw. Hi Chris thanks in advance for any tips. When the lambda is 1.0, the displayed AFR is 14.7;1 REGARDLESS OF THE FUEL. The AFR was pretty consistent around 13. Fuel Flow lb / h = 12.1 You'll have to go back and forth a couple of times to get it just right. I recently had IAC issues identical to what you describe. However, I have what I will call a whistle at a throttle position on 35 - 50. After it starts it idles around my 960rpm setting + or - 100rpm. My Sniper is 99% great! Any help would b great. It felt like it was flooding out at low speed, low. 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. Shut off the engine, ensure power to the Sniper is switched off. Simply use your handheld controller and go to the Tuning > Advanced > Advanced Idle > Idle Speed screen and click on the Idle Speed Curve function. You can disable the idle spark control at the locations below. The symptoms I had was a low cold start idle and going lean coming to a stop. We're having trouble with a Ford Maverick 302 V8, using ethanol. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. lower until I turn down the set screw. I had a customer recently with a high idle problem that he eventually traced to pad plug on one of the vacuum ports. Properly configured, the Sniper does a fantastic job of responding to the transition from Park to Drive. First, I'm kind of insistent about not changing any of the default settings unless the vehicle absolutely will not cooperate enough to drive/learn, and only then if you have a specific understanding of the problem and a specific solution. Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. The Sniper even has a feature that allows it to use the idle timing to control the idle speed. When I finished the install on my C10, I set it as follows: 13.1 at idle, 14.2 at cruise, and 12.9 at WOT. Note too that the larger the throttle stab, the more brief the time in that cell and the more gradual the change.Here's what I recommend: Get somewhere where you can repeatedly stop and go. At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. This happens no matter how much I adjust the idle screw. idles good, runs amazing. 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. A good example of why it's so important to run a good pre filter in the fuel line. Start with the most gradual throttle input you need to launch well, then slightly increase until you feel some stumble. Watch videos on installation hints and if you haven't yet, download & read every Sniper installation guide you can find online. Then do it just a bit faster--just enough for it to bog a bit. It turns out that some of the Snipers are shipping with the minus 40-degree setting drastically lower, as shown in the following image. That initial rev is going to be determined by your IAC Park Position. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. If you use your handheld to go here: All times are GMT-6. If the TPS reading on your Sniper EFI System does not reset to zero that is a problem that needs to be addressed. Which means you either need to increase that number or increase the ramp decay time. your IAC is at zero. Once it commands that high idle I haven't found anything to return it to normal, other than shutting it down and restarting. I keep doing that with the same result. After the start process, If the idle speed is higher than the target idle then the IAC should begin closing as long as the TPS is below 2%. Switch power to the Sniper on and crank the engine. 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. But nothing beats a good solid gut-check Copyright 2017 Cyberspace Automotive Performance, Inc. All Rights Reserved. If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. 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.