holley sniper efi iac problems

The fact that it ran so (at times) with 90+ PSI fuel pressure is a testimony to the Holley's closed-loop technology. So try changing your IAC hold value slightly:Tuning : Advanced : Adv. It will learn the fueling eventually either way, it's just that one might get you there a little faster.If the idle is fine at start-up but then increases after you depress the throttle then you might need to lower your IAC Hold Position a bit. Hey Tommy, we've got at least one thing in common. It wont fire up. 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. No matter what do, my idle will not drop below 1350-1400 RPM when the engine warms. Check fuel pressure too (. If it creates an issue (not normally the case) then you'll know. The noise changes sound with the throttle position. Somehow air is entering the engine that was not entering the engine when you originally set the idle speed screw. A good example of why it's so important to run a good pre filter in the fuel line. If your RPM is 2000, your TPS is 0, and your IAC is not closing, then there is some problem. any advise would be appreciated. I started with right after I first adjusted for 2% IAC and took pics about every 30 seconds over about 2 minutes. That initial rev is going to be determined by your IAC Park Position. In that case, and if you have an EGR valve, I might be suspicious of something going on there. Thank you. There are two ways to address this--you can let the system learn or you can manually adjust the acceleration enrichment. One way is to very carefully watch the handheld monitor, and that may be adequate. 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. Copyright 2017 Cyberspace Automotive Performance, Inc. All Rights Reserved. You might have a bad O2 sensor, really bad exhaust leak or a problem with the ECU. If you go too low then it may stumble or even stall when coming off of throttle. Is there away to program the ecu to compensate for this at start up. I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. issue. I put sniper on in hopes to be able to just turn key and start without fumbling with pedal to keep it going and to correct idle drop when ac kicks on. hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I Intake has been on and off 3 times no change. :-) Just don't let the parts go flying. I have heard some guys complain that the idle is too good and they can't hear their cam anymore I'm kind of like that. Relatively new Sniper EFI install on a '69 Mustang 302. I have been able to get it pretty I believe because the TPS is not registering. In this short video you learn to replace the IAC. 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. I've been messing around for a bit trying to eliminate any possible vacuum leaks. Thanks for any info./insight you can provide, Mark. Then it started behaving oddly. One of the best Ive seen so far. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. Hopefully replacing the pump again will resolve both issuesWhoa. I'd suggest that you assume everything the previous owner did was wrong until you can prove that it was done correctly. Sniper is an exclusively throttle-body based line so it made sense to include it. If you have a bellcrank in your throttle linkage, ensure that the linkage is not engaging the bellcrank at an angle greater than 45 degrees at either end of the throw. no timing control. However, whenever you start changing things, you can get into a chain reaction. Or alternator? Check the Distributor Tach Connection to the EFI. 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. Given the circumstances I would say that it is either the IAC motor itself or RFI but you seem to have ruled both of those out. We offer some tips to help with that. You mentioned going from 13.5 to 14.2 but you'd want to go in the other direction--maybe to 13.2. 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. Once you confirm the operation of your IAC then it's time to read my article on Solving RFI Problems. We're having trouble with a Ford Maverick 302 V8, using ethanol. I got it home, checked it all over, everything is hooked up correctly. A few, however, get tangled up getting the idle control working just the way they want. 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? This was an issue in the earliest version of the Sniper firmware. Ensure all your sensors are displaying proper values. Hey Chris! 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. Going lower with the blanking might pay dividends, but there is so little room below 7/8 that you will quickly be in a range where every tiny variation in the TPS or MAP is throwing extra fuel into the engine. I had a customer recently with a high idle problem that he eventually traced to pad plug on one of the vacuum ports. I know this is old, but I bought and installed a Sniper kit in 9/18. The learn percentage should gradually decrease to virtually nothing as the map plus learn table begin to get more and more accurate to your specific setup. 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. Anyway I have a 327 sbc in a 1987 Monte SS with a T5 5 speed and 3:73 posi rear. After pumping the pedal a few times at different times it dropped to zero and started to work. So I had my Idle set up perfect, with idle timing control off and engine hot the IAC was right at 2-4%. Watch videos on installation hints and if you haven't yet, download & read every Sniper installation guide you can find online. Fortunately, Holley has another product that can solve that: Hydramat.. Hydramat is not inexpensive but you won't believe what it can do. knowledge with the sniper efi setup. 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 figured out I was going the wrong direction when I was messing with the AFR programming. Hello If you don't have a working coolant temperature sensor then it will never bring the idle speed down. If you have performed the adjustments above and still have RPM issues, it's time to look for clues. 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. OK, I did the baseline idle speed screw setting. 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 have an entirely separate article on Solving RF Intereference Issues. Thank you so much for your follow-up. Am I missing something. I did change the -40 thing also. I think I figured some of my problems outI'll try to explain. AGAIN This is Intermittent meaning on a recent trip I stopped 3 times and issued occurred once. The person I bought it from said he never could get it to run for more than a few seconds. 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. When you key on, you will hear three distinct sounds: The ECU initializing the IAC, the fuel pump priming, and the injectors firing their prime shot. I will let you know what the results are. Those don't impact the way the engine runs and can cause the whistle sound you describe. I installed my Sniper and the engine fired up great. Doesn't want to start, runs like crap. Initial thought is timing but Im running a cd box and the ecu is not controlling and I did not physically change it during the install. Your issues are likely related to one of these two things. 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. If no air is passing (and the idle doesn't drop) then your IAC is working. 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. 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. If the IAC number is increased during this high idle, review the points about high idle from tuning issues. it seems to ramp to 60 psi on the initial prime, but as soon as the motor start the psi spikes.I guess a workaround would be an inline return/filter regulator? Two things to keep in mind as you do that. I've been trying to correct that 1% small issue/annoyance. So you installed your Holley Sniper. In the setup, I set the hot idle for 850. Ok, so I'm stumped! 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. 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. Since a key cycle resets it to 0 and out to 30 or wherever 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. It might be necessary to insulate or re-route your fuel lines if this can't be solved any other way. Engine warms up to 195 degrees and stays. He said they have been having an issue with these lately. All times are GMT-6. Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. While confirming, in the handheld ensure that the Reference Angle is set to 57.5 and that the Inductive Delay is set to 100. 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. IAC looks good once it finally s fires. Incorrect connections will result in excessive resistance. Holley Sniper Iac Delete Another suggestion is to add an extra turn to the spring built into the linkage to increase the closing force on the throttle shaft. have the system learn the higher speeds? If there is an issue with using the Sniper EFI TPS signal, is there a remote TPS or an adaptor for the Sniper EFI that allows the TPS signal to be accessed for the transmission. Hot start it most of the time wont start unless I give it a little throttle. Though it started and ran good, it was dumping fuel and would not lean out to AFR set points. The engine ran so good, I would have never suspected the Fuel Pressure to be an 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. The progressive link can be a great solution on standard (non-Stealth) throttle bodies but I would install this LAST after everything else is working perfectly. IAC percentage is 5 to 10% when idling with fans on, What you're experiencing is the delay time between the ECU sensing the additional load and the IAC actually increasing the RPM. carburetor setup, but it does blow when I can't jump on the highway like I use Yes, you are correct. I installed the Holley Sniper in my Chevelle this winter with a brand new BluePrint 496. The problem I experience is that after driving for about 10-15 minutes, the car starts idle to high. Then your low idle problem will go away. It runs perfectly fine other wise. When you have the issue you should disconnect all hoses and plug the ports on the Sniper. Please let us know how this works out for you! If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. 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%. 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. Don't be surprised if one or the other is slightly open. 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. EFI System Pro had everything I needed for my EFI upgrade. 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. Thank you very much. The hold position is part of the response that keeps the car from dying when you come off the throttle. Price Point: $, Advanced throttle body injection systems capable of transmission control and more. It'll start & run till it's warm, then when I try setting the IAC every time, I try getting it between the 2 & 8% it quits. In your case, however, I think you're close to getting it running. The IAC is hanging open and not really at 0. I will turn it up some more.Is this something that the ECU will learn? You are looking in the right area but I would probably not change the ROC blanking. Both Sniper and trans controller grounds were direct to the battery ground, as they should be. If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. But I think it is safe to say that you are now at a point were some manual tuning is a good idea. (Note: in the original version of this post we had a section about checking the idle speed curve setting. Nice to meet you. Just getting it to act right at startup is a struggle. Of the two options, I generally recommend the self-learn. This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. If you are idling at 2100 RPM (based on a default IAC Hold position of 30%) and your target idle speed is 900, then the ECU is not going to try to idle down. We can not hit it at all, we hit the pedal abruptly, the engine gives a lot of excess fuel, the AFR gets super poor at first, the car stops, then the AFR gets super rich and the car runs until it cleans up. All of the wiring exits below the rear fuel injector cover, for a completely stealth installation. 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. 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. First thing I would check One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. And, hopefully, within those degrees you will find a place where you don't get the whistle. 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. I think you will find that it will learn its way through this. Engine has never stalled with Sniper system, once placed in Drive it just goes!!! Don't know if I should put this in a separate post. The "Gauge Text" is what would be shown on a 2-1/16 gauge or the Avenger handheld display. Thank you for any advice. 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.) Featured Products Sniper EFI $7.07 - $2,457.95 470 Products View Parts author Staff Writer 1711 Posts An Article About Video tech Sniper EFI Videos Sniper EFI Tech Sniper EFI sniper Installation 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. normal city driving, I no longer have other problems I had with the original Always had to set idle above 950. 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. Sniper is still learning so it will continue to improve.Second, you may have heard the phrase, "correlation is not causation." Using a Snap-on variable timing light so this is why I say timing is perfect. The idle is 1350-1400 with the idle screw at initial contact. (Do this while you are cranking.) Part# 538-13. Take a drive and stop somewhere for 30 minutes, CTS is 170 when engine was shutoff. Idle > IAC Kick. Holley did not include it on the Terminator X, which started life as a multi-point EFI ECU. It really takes a lot of throttle tip-ins before you get anywhere near "learned" in this part of the fuel map.Based on your description, it sounds like you have a lean stumble. EFI parts, including the throttle body, and the problem persists.Please give me a hand. holley efi. Short drives is fine then it'll Could be a bad IAC motor, replace it and see if that solves the problem. The fix? Shut it off and immediately restarted and idle was now 880 with IAC at 8.If this is a vacuum leak I can't figure out what would cause it to go away immediately after shutting down the car and restarting. When I see that your TPS is 1%, that tells me that you may have an RFI problem. It's going to be really difficult to nail down the problem with the several simultaneous changes that you've made. About two minutes after I get it set at 850 & 5%, it has progressed to 100%. The solution is to either lower the IAC hold position or increase the RPM above idle to start ramp (default is 1000 RPM). It does this with the engine off. It appears that I could now use the dongle and a laptop to custom tune for idle issues if needed.

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