Ensure there isn't a vacuum leak causing the IAC Position to drop to 0%. I've tried repeatedly re-creating the scenario in hopes that the E.C.M. If your fuel pressure is at or about 60 PSI then visually inspect the barrels of the throttle body while having someone key on the Sniper. Once you've done this, the next natural step is to transfer the learn table to the base map, then go in and smooth out the sharp edges, which are going to be at these transitional states. 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. At low levels RF interference will often reset the ECU so quickly that the engine will not stall. I believe because the TPS is not registering. After this whole process, the car normally rotates without a very abrupt pedal. 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. Then, when you experience the high idle, note if the IAC number has increased. Your second problem should be a bit more concerning. That is the only way to fly. I' m going to put the 3 rd new pump this coming friday. Turning off and then on again, the engine returns to normal. 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. But, if the idle is so high that it is making you crazy then you might try dropping that number just a bit. Adding a wrap to the return spring on the shaft is one alternative to solving this. Ok, so I'm stumped! 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. Physially manipulating the linkage by hand will generally reveal if you have a sticking linkage that is preventing the TPS from returning from zero. I believe that for the HyperSpark the Reference Angle should be 57.5. If you haven't confirmed that they it is worth checking. Resistance results in heat and heat results in more resistance. 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'm new to EFI and have no idea what to try next. One way is to very carefully watch the handheld monitor, and that may be adequate. I am having an issue with the IAC on the Sniper. RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the 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.
Holley Sniper IAC Surging???? A problem since day 1 - YouTube By the way, this is a new installation on a 69 Camaro, stock 350, dual sync, etc. Hi Chris , greetings from Down Under (AUS) Just a note on the hi fuel pressure issue .
Holley Sniper EFI Problems: Best Fixes According to Manufacturer Could the IAC be broken/malfunctioning? I have adjusted many settings and eventually mess it up and go back to the original map. All times are GMT-6. An under-sized filter will allow part- throttle operation but fuel pressure will drop at WOT and run very lean - perhaps surge under power. Let me be perfectly clear: If your engine will not drop below 1350 RPM with the idle speed screw turned all the way out then you have an air leak. Even at 0% it's sucking a bunch of air through the IAC port. 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. 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. I keep doing that with the same result. If no air is passing (and the idle doesn't drop) then your IAC is working. A simple remove & clean will remedy this . I think that the more important point is that Holley kept sending him units until everything was working. Give that a go and see if you don't make some progress! But if you can datalog the bog you can know much more precisely what is happening. I am having an idle issue (other than that is absolutely perfect). If your RPM is 2000, your TPS is 0, and your IAC is not closing, then there is some problem. Not to bandstand here but this is the point when where you bought your system is so important. i would have been happy to answer there. Tuning > Advanced > Adv Idle > IAC Startup 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. Cracked casing from a side cover screw being installed crossed threaded. Bottom line ismy first one must have been faulty. Again, I would lean on that solution to let the vehicle drive/learn before you try to "fix" anything. EFI parts, including the throttle body, and the problem persists.Please give me a hand. The first 250-300 miles were amazing as the Sniper EFI worked flawlessly. I'm wonder if the iac can cause this. installing and cruising down the highway 70 mph I just wonder if all I have to do There are six different acceleration enrichment tables that you can tweak and that may be the way to go. For someone in your position, it will become an indispensable tool in your tool box. In the wizard I set my Idle to 500RPM but it never got slower than 800RPM, if I run the wizard again and lower to 400 RPM then it never gets lower than 700RPM.After reading about the Idle Speed curver I checked its settings and found that the curve was 300rpm faster at every point over the temp range no matter what temp I had, I adjusted the curve to match what I put in on the wizard and now the RPM is correct, I'd say you have a bug in the wizard.Idle Speed > Idle Speed Curve: Here is where the lack of coolant temperature is going to affect you. For the first couple of drives it was running well, Sniper EFI was working exactly as advertised. Those don't impact the way the engine runs and can cause the whistle sound you describe. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? If you go too low then it may stumble or even stall when coming off of throttle. That is the IAC hold position. Any suggestions would be appreciated. Note that Brazilian gasoline has 27% ethyl alcohol. Hot start it most of the time wont start unless I give it a little throttle. Or ?I have put a fuel pressure gauge right at the inlet of the sniper and it is reading 60-64 psi. MSD pro billet and 6AL box started up the engine. I did read some comments on regulator issues is there a way to check it for an issue ? After pumping the pedal a few times at different times it dropped to zero and started to work. Should the iac% fluctuate? Duty Cycle% = 3 I can adjust at 160deg, but my fans turn on at 180deg. I think in some of the Wizards with the handheld it doesn't use 57.5 as the default. Therefore The iac will always be at 10% now, correct? After a stall the car will restart but will be in a high idle. 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!
Holley Sniper high RPM - IAC problem? I do know that the reference angle is 57.5, the inductive delay says 100.0. Seems like its too slow to grab idle when ac kicks on. I straightened that out, got it running and that's where it goes downhill. If that happens then follow my 10-step process shown above. Two months fighting, cursing, not getting any help from Holley OR the forum, and a stupid little tin plate. No air should be able to pass. idle counts from 0. And your understanding of how the throttle position affects idle is exactly correct. Some have suggested mis-setting sets the idle speed at 850 RPM but I suspect it is not a fixed number but rather a delta of about 300 RPM above the target. 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. back upthe RPMs shoot up to anywhere between 1500 and 2000 and they will not get Great work, expert! 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. As you have noted, each time the idle goes up.
Holley sniper, bogging/ losing power "NOW FIXED" Have a look--I think this is going to allow you to fix your idle problem. One of the great features of Holley's Sniper is the ability to set your air/fuel ratio (AFR) where you want it. no timing control.
Holley Sniper EFI Was perfect idle iac reading 3. 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. Suddenly, the engine accelerates alone, hears a great deal of air being sucked in, I've been trying to correct that 1% small issue/annoyance. Should I just disable idle timing control? Ensure all your sensors are displaying proper values. Realize that when you drop the throttle, the engine enters a condition it will only see for a fraction of a second at a time. Yes its at 95lbs, needless to say he promised a new regulator would be in the The next time it happens is the perfect opportunity to find the problem. I have driven it a few times maybe 100 miles or so. The Sniper resets the TPS to 0% each time that you key the system on. I didn't find your site until I was having trouble. One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. So something is triggering the ECU to be in Open Loop. About two minutes after I get it set at 850 & 5%, it has progressed to 100%. 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. I installed another return spring for the rear plates problem solved instantly. After speaking with Holley Tech Support and Tech Support from where I purchased the systemthey decided to replace it. I've abbreviated it just a little bit but am appreciative of the added insight your comments provided.Off-idle performance can really be a challenge to self-learn but be assured that it can almost always be done. Yes, you are correct. 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.
Holley Sniper IAC | Chevy Nova Forum When I first told him to check for leaks he looked back there and said "all good". That is not something I'd ignore. Holley EFI Electronic Fuel Pressure GaugeI think its a little ridiculous that I cant see fuel pressure on the display even though its measuring it but whatever. I did buy the Sniper from you guys and the service was fantastic. When you open your IAC to 30% you are naturally going to have a high idle condition. If the IAC number is increased during this high idle, review the points about high idle from tuning issues. A good example of why it's so important to run a good pre filter in the fuel line. And Earl's makes a fantastic little 100 PSI gauge. 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. Price Point: $, Advanced throttle body injection systems capable of transmission control and more. 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. If I block off the iac with tape , I can get it to somewhat idle, but its not consistent. It started right up and we did your idle control fix and all is good at idle. I appreciate everything you are saying. Free ground shipping regardless of order size! I've been messing around for a bit trying to eliminate any possible vacuum leaks. That's what you're seeing. I used the Casper's Electronics 108103 splitter and carefully soldered my connections. Incorrect connections will result in excessive resistance. I did notice that when I thought I had it set By the way your site and your accessory products are nice. 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. A problem since day 1 - YouTube Leave a comment if you've had this issue and how you resolved. (Do this while you are cranking.) What can I do? Honestly, I've never seen this happen but if the butterflies were misaligned on the shafts it could allow too much air to enter. If idle drops below 800 it wont come back itll chug around 300 rpm for a few seconds then die. Hello Chris. That is the default "Clear Flood" TPS setting and turns all fuel off until the engine cranks. If I put the truck in neutral the TPMS will raise all the way up over 2000. Capability Range: Professional If it does then you can put on a heavier spring so the advance doesn't come in as fast, or use a lighter weight. And so glad you guys are enjoying the Sniper EFI system. My Sniper is 99% great! You are aware of the idle-up problem. Now it's at 5% on a big cam 440 Mopar. Cycle the ignition as instructed by the handheld and then navigate to the distributor setup screen. I'm new to the efi thing and any help would be seriously appreciated. 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. It only lowers to 2-6% when I take my foot off the gas. Going back to what you said. Thanks, That is an strange situation. :-). Bolt on 4150 Flange Carburetor Replacement. In the setup, I set the hot idle for 850. But they are 100% committed to your satisfaction. that my Air/Fuel ration was 15:1 and I believe the target is 13.5:1. Thanks again for your insights! I figured out I was going the wrong direction when I was messing with the AFR programming. Any suggestions? I took some pics of the sensors page this morning after the car warmed up. If you go too high then the motor will not return to your target idle when you come off the throttle. It could be that the air flow across the secondaries as they are opening is creating that whistle but that isn't commonly the case.Did you check for leaks around the gasket of the air cleaner? When running it will only stay in closed loop and learn at idle. That, on top of your air leak, is allowing the engine to idle at 2400 RPM. But there are several degrees of play there in which it should still work fine. I then saw you guys have an awesome little gauge that can hookup inline to the snipers existing fuel feed?? Ensure that the secondary linkage is completely closed (both visually and manually.). Thanks for the info Chris. Confirm the placement of all wiring, ensure that the WBO2 sensor is positioned properly, etc. I drove it a bunch more yesterday afternoon/evening and the same thing happened several times. First, recognize that the IAC and the TPS are not inter-related in any way. Price Point: $$$. 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. At some point you come upon problems that evade the easy answers and this is a good example. If they are closed, check the primaries. Also its extremely rich at idle. 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. 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. itself out and hold idleeventually stalling. 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. Then it started behaving oddly. I went on the good ole interweb and found your website which was VERY helpful! shut truck off. Chris's Idle Speed Adjustment Instructions*: *Note: If you are using your Sniper to control ignition timing then I recommend that before you start this process you disable idle spark control If you are trying to do this while the ECU is simultaneously trying to bring your idle under control by adjusting the advance it is going to be counter-productive. Then follow all of the instructions above, including confirming the idle speed curve setting at -40 degress as well as following my 10-step process for setting the idle. 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. If I put the vehicle in gear the idle gets higher with temp. :-). 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.
Sniper EFI Initial Startup and Troubleshooting Staff Writer 01/20/2020 Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. 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. Now it registers zero and I have good idle but it will not register until it hits 60 and up. If you did not rotate the distributor to set the actual timing to 15 that might be the only issue. Holly offers a very nice Analog-Style Fuel Pressure Gauge that is another option. Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to Well you were right air was entering from another source. Im not sure what its doing, have messed with after start fuel, fuel at cranking.
Solving Holley Sniper High Idle Issues - EFISystemPro.com 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. Thank you very much. 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. If your mixture is too rich, it means there's too much fuel and not enough air. Observing the temperature on the 3.5-inch handheld (only), wait for the temperature to achieve 160 degrees F. Once above 160 degrees, turn the idle speed screw so that the idle is about 50 RPM below your target idle speed set in step 1, above. If I were there in person I would test the function of the IAC (see this article.) The window you saw in the image above pops up. 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. This item: Holley - 543-105 EFI Idle Air Control Motor , Black $71.72 Holley Sniper EFI 870001 Throttle Position Sensor $34.60 Holley 860004-1 92MM Sniper Throttle BDY $223.93 Customers who viewed this item also viewed Page 1 of 1 Start over Holley EFI Idle Air Control (Iac) Valve Motor 30 13 offers from $79.56 If I keep the rpm's up it does fine but my clutch can't keep up with this for long.Also when I cover the IAC port the engine dies. Good I had this same exact issue. ?I never had my Carb Cold start RPM any higher then 1600 RPM.THANK YOU. Hello Chris. They always responded to my questions with guidance that helped me choose the right system for me. 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. You'll be amazed at how much of this just "goes away" when you drive it enough. 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. In the Wizard, select the stock cam setting. :-). Earl's Mechanical Fuel Pressure GaugeI could use that for a quick troubleshooting for 1/3rd the cost of the Holley one. Will restart but only for a minute or so a couple of times then shuts down fuel delivery and will not restart. But I can tell you that for most people who try this it introduces so much RFI onto the Sniper that it never works right. 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. If I try and get the 2-10% i get all the way up to 1200 rpm. A question I cannot get a 100% answer on is can you piggy back off the Sniper EFI TPS for an electronic transmission? However based on your reply I connected the Fuel Pressure gauge and Save Share. to. 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.