That is likely just confusing the issue.Instead, choose whichever setup most resembles your camshaft and stick with that. The first thing I'd do is check your fuel pressure with a gauge like this. Shut off car/restart and it's back to idle at If that happens then follow my 10-step process shown above. No timing control, coil negative ignition type. To do this, open up the Initial Startup gauge screen that was used in section 17.0. That will happen occasionally, but less as time goes and on and the engine tune stabilizes. That, I am afraid, is going to involve a little bit of luck if you don't want to create a 250 MB data log. I installed another return spring for the rear plates problem solved instantly. 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. As I have it set right now, my idle at park is in the high 700s and my desired idle in gear is set at about 700 cold (80 degrees) and gradually lowers to 590 once engine temp reaches 160 degrees. Target AFR at idle is 13.8%. The headache is the Acceleration Enrichment. Ok, so there are a couple peculiar things going on here. you have it set. Watch videos on installation hints and if you haven't yet, download & read every Sniper installation guide you can find online. When you open your IAC to 30% you are naturally going to have a high idle condition. Running new vintage air system so the is only a single power wire to compressor thats why I asked if I needed to run input wire to ac relay or if iac would pick it up fast enough(which its not). 680-700.I can't find any reason other than it looses where it is in the firmware with When I shut it off then start it This only happens when coming to a stop and the idle is ramping down to the set idle RPM. I' m going to put the 3 rd new pump this coming friday. It's going to be really difficult to nail down the problem with the several simultaneous changes that you've made. I appreciate everything you are saying. You just need to go back through the IAC adjustment procedure now that idle timing control is enabled. started up the engine. Seems to behave more better now. Thanks for any help. My Sniper started having a ticking noise-- I have 90 miles on my Sniper, but this started the last 10 miles or so: it still drives fine, but it worries me so i've stopped driving it for now. Thanks for the information you have provided on this site. Hello Chris. :-). Did your process to adjust idle to 860. Shutoff engine wait 30 seconds, turn key wait for display to come up, start engine. 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. It could be that you've left a vacuum port unplugged, it could be that the throttle plates are misaligned (unlikely), it could be that your IAC is not closing properly. Honestly, I've never seen this happen but if the butterflies were misaligned on the shafts it could allow too much air to enter. NOTE: Do not attempt to set the target idle speed and IAC position until the engine is above 160F! Remove the tape from the IAC breather hole and restart the engine. The Street/Strip and race cam setups tend to be too rich initially. The engine runs beautifully, with perfect idle at 650 RPM, but every now and then I hear the IAC give a sort of "snap" and the idle is at 1200 RPM. Take a drive and stop somewhere for 30 minutes, CTS is 170 when engine was shutoff. first attempt but as it tries to idle down to the target RPMsit can never even Two things to keep in mind as you do that. Do I need to try taping up the IAC port and setting the idle off the idle screw? If you use your handheld to go here: Okay, try my method. An undersized or partially plugged fuel filter is a classic EFI installation mistake. The throttle position should be zero. 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. is jumping all over the place when you experience this condition, it does not You will have to do this until the TPS stays at 0% when the throttle is closed. Relatively new Sniper EFI install on a '69 Mustang 302. The engine ran so good, I would have never suspected the Fuel Pressure to be an Good The IAC is hanging open and not really at 0. Everything was working perfectly and I shut off the engine. However I do have a couple of issues I hope you can help me resolve. The car would idle, I could hit the gas rev the car up and it ran great I also noticed two nice black spots on my garage floor from the exhaust. 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. Often, folks will say, "I did everything you said. If I go any more it will ping. 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. is the fuel pressure. Mechanical Fuel Pressure Gauge on the inlet of your Sniper, now is the time. You have to remove all hoses in order to debug the problem. The only way to confirm RFI problems is by doing a data log. Check fuel pressure too (. Any suggestions? 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. Thank you. 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 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. If you drop it too far the engine will stumble or stall when coming off the throttle with the car out of gear, so you'll know when you've gone too far. When I first told him to check for leaks he looked back there and said "all good". 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%. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds This page was generated at 12:25 AM. After a stall the car will restart but will be in a high idle. And Earl's makes a fantastic little 100 PSI gauge. idles good, runs amazing. Bolt-on carburetor style EFI for your classic car or truck. 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. Sniper is still learning so it will continue to improve.Second, you may have heard the phrase, "correlation is not causation." The TPS will go red with a -15 and the AFR reads heating for a split second, then the idle kicks up to 2000RPM. See these. Is this normal ? 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. Hey Chris! It felt like it was flooding out at low speed, low. You might have a bad O2 sensor, really bad exhaust leak or a problem with the ECU. Holley documentation and videos didn't work and the $300 I paid for "expert" tuning didn't work either. I'm so glad you found this helpful--that makes my day!Don't get too concerned about the specific learn percentage. Perfectif you have the original synchronous linkage. Any help would b great. If I adjust idle screw out to get the tps to zero or even 1% the engine will not idle. Thanks, That is an strange situation. ps. These problems will go away when you do that. But another thing to consider is adjusting your target A/F ratio. That is the IAC hold position. The Sniper EFI Manal says not to but many EFI installers have informed me that the transmission only reads the 5V TPS signal from the Sniper EFI & does not draw any power so will not affect the Sniper EFI TPS output. The solution is to either lower the IAC hold position or increase the RPM above idle to start ramp (default is 1000 RPM). When I see that your TPS is 1%, that tells me that you may have an RFI problem. applies here because it is so important to realize that just because the IAC At some point you come upon problems that evade the easy answers and this is a good example. 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. But I think it is safe to say that you are now at a point were some manual tuning is a good idea. They tell you to ask call Holley. Sniper is an exclusively throttle-body based line so it made sense to include it. Interesting situation you have. When I put it in gear, it drops so low that it will stall if I don't add throttle. The engine has 14: 1 compression ratio, we can not use gasoline. When I covered the IAC with my finger, the RPM dropped so low it stalled. They are prone to be inaccurate. Once it commands that high idle I haven't found anything to return it to normal, other than shutting it down and restarting. If you go too high then the motor will not return to your target idle when you come off the throttle. Let But when you have it then you can look for exactly what the IAC is doing at that point, and if there is anything that might lead to this happening. So this is my issue ( I did just email Holly). When I put it in gear, it drops so low that it will stall if I don't add throttle. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! 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 I would not expect that an electric fan would create a noticeable load on the engine but if it did then you'd want to set the idle screw when the fan was not running. When I turn the key on I can hear it prime, but I don't think im getting enough fuel. Free ground shipping regardless of order size! That, on top of your air leak, is allowing the engine to idle at 2400 RPM. Those don't impact the way the engine runs and can cause the whistle sound you describe. (Note: in the original version of this post we had a section about checking the idle speed curve setting. 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. i would have been happy to answer there. Since that has long been corrected we have moved that information to the bottom of the article.). I'm running a 408 sbc. 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. 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. Is there away to lean the idle out? If I put the vehicle in gear the idle gets higher with temp. However, I have what I will call a whistle at a throttle position on 35 - 50. Short drives is fine then it'll Thanks again for your insights! Be sure to re-enable it once you get your idle tuned. It's pretty hard to get the header tubes glowing at idle with a lean AFR. 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. I watched the butterflies start to open at about 35 on TPS. The tps has slotted holes, can you adjust it to get to zero? If you have somehow overlooked this, start here: Holley Idle Speed Adjustment Instructions: Once the engine is up to operating temperature, the idle speed can be set to what was configured in the Wizard. And the rather cavalier "Absolutely!" I'll bet you find that you can get it working great without any manual tuning. When I put it in park the idle RPM was 2100-2200 each time. If I were there in person I would test the function of the IAC (see this article.) Nice to meet you. So you installed your Holley Sniper. The fact that it ran so (at times) with 90+ PSI fuel pressure is a testimony to the Holley's closed-loop technology. I guess we can't have everything. In most cases the IAC (Idle Air Control) circuit is the source of the whistle. The window you saw in the image above pops up. School's out for spring break this week though so I'm covering for employees on vacation. any ideas? 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! I've not heard of any others with this exact issue so I don't think it is a common problem. I installed the Sniper on my 1978 Ford F-100 with a small block They also worked with me on a sale I missed and price matched those parts. This is normally used as an A/C idle-up circuit. Idle was around 1000 mark and iac 0. MAP Sensor. Ive tried setting the prime setting above 150 but it wont take, it always goes back to 150. If you have any questions about the car/setup let me know. Thanks for sharing that, Jason--great info! 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. Only show this user . Then your low idle problem will go away. First, recognize that the amount below your target where you set the hard idle will be different on different engines. I'm new to EFI and have no idea what to try next. Cracked casing from a side cover screw being installed crossed threaded. Wish I knew about it before I made my purchase. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. Get a solid feeling for where it is when the engine is warm and the idle speed is correct. Once you know that then you can work on those problems. I used the Casper's Electronics 108103 splitter and carefully soldered my connections. would correct it (as it has for a multitude of other drive-ability issues) but this one little glitch seems out of it's range. 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. I ask because I'm using a PCV valve with my Sniper and have random idle issues as well. Also ensure the TPS Position returns to zero at idle, & the IAC Hold Position isn't setup too high. I can get it to fire up on the 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. Can the return line be an issue?So far this sounds like an ideal setup.>I have had 2 faulty gpa-4 255 walbro pumps go bad. In fact, it is those users who seem to end up most impressed with the system. You should get a light spray evenly distributed in all four barrels. Even at 0% it's sucking a bunch of air through the IAC port. Start engine let it warm up to 160, learn mode is learning. Thanks for any info./insight you can provide, Mark. If your RPM is 2000, your TPS is 0, and your IAC is not closing, then there is some problem. Don't be surprised if one or the other is slightly open. Several good bits here. If the solutions suggested above are not working then you need to review my article on IAC Testing Procedures. I do know that the reference angle is 57.5, the inductive delay says 100.0. The idle will not return to the set value.The second issue is the same as the first but the motor will stall out. Suddenly, the engine accelerates alone, hears a great deal of air being sucked in, I have an entirely separate article on Solving RF Intereference Issues. Incorrect connections will result in excessive resistance. 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. That's a nice change of pace--a low idle issue! I would recommend that you call first thing in the morning, as they tend to get quite busy during the day and wait times can get long. Another suggestion is to add an extra turn to the spring built into the linkage to increase the closing force on the throttle shaft. I recently install a sniper efi. But get that fuel system fixed before going any further. Even then, recognize that over time the IAC will need to be readjusted to compensate for minor changes that will cause it to drift. Thanks for all your help Chris! 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. 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. 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. 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. Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. Don't know if I should put this in a separate post. mean that the IAC is causing it. On a cold start it will idle at 750 everytime, But if its hot start it will jump upto 1600rpm for 2 seconds then come back to 750. I readjusted my IAC, now it's perfect. By the way, this is a new installation on a 69 Camaro, stock 350, dual sync, etc. I drove it a bunch more yesterday afternoon/evening and the same thing happened several times. I looking for your expert opinion. 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. One of the signs of a vehicle with a rough idle is a faulty Idle Air Control (IAC) Motor. I've helped folks work through a number of challenges with their Sniper EFI System installations. I set the AFR at 13.5 and all is good now. Contact whomever sold you your system or Holley directly. It appears that I could now use the dongle and a laptop to custom tune for idle issues if needed. I also tried changing roc/map to 8 from 15 again no change at all.My ve table is smooth and tuned I even changed my AFR to 13.5 from 14.2 and no change at all. Idles ok, runs great cruising, but from a stand still or downshifting and making a turn, when I get back into it, it wants to fall on its face. Though they both are indications of the amount of opening through the throttle body, the TPS is the throttle opening percentage and the IAC number tells us how far the IAC stepper motor is opening the bypass air circuit.If I understand you correctly you are saying that the TPS reads somewhat normally (traveling from 9% to 100% or so) but that when you cycle the key it once again starts at 9%.