Physially manipulating the linkage by hand will generally reveal if you have a sticking linkage that is preventing the TPS from returning from zero. If you have performed the adjustments above and still have RPM issues, it's time to look for clues. Running the vacuum advance and of course I time it disconnected. ps. That is what I really respect about Holley. Thanks for the information you have provided on this site. The Tech Tips and discussions are also great! I installed another return spring for the rear plates problem solved instantly. At idle my IAC is 3-4, AFR around 13-14, TPS is 0, timing 15-17. I was looking at a data log from my truck earlier this week and noted that at idle my IAC was zero. About two minutes after I get it set at 850 & 5%, it has progressed to 100%. I'd recommend you contact Holley Tech support to get their input (1-866-464-6553; call early for the shortest wait times.) :-). It does this with the engine off. Don't try to correct for the fuel. 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. After this whole process, the car normally rotates without a very abrupt pedal. I am Japanese who attached Sniper EFI. 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. Advanced throttle body injection systems capable of transmission control and more. All times are GMT-6. 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. Jun 12, 2021. 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. Full product line and accessories at excellent pricing. If you don't have a working coolant temperature sensor then it will never bring the idle speed down. Well you were right air was entering from another source. So you installed your Holley Sniper. These aren't generic newsletters either but instead personalized emails. In that case, and if you have an EGR valve, I might be suspicious of something going on there. Incorrect connections will result in excessive resistance. All in all, considering the system has been installed for less than 2 hours drive time we're BLOWN AWAY at how quickly it is "learning" this engine. Have you confirmed your fuel pressure at idle is 60 PSI? I have a feeling it's something simple but I thought I'd ask you first before I inadvertently change something that affects other areas. The only way to do this is by installing a mechanical fuel pressure gauge. Target AFR, A / F = 13.5 This is normally used as an A/C idle-up circuit. If the connection is loose it will cause the system to shut fuel off because the signal telling the EFI the motor is turning stops (to prevent excess fuel from being dumped in the motor). Price Point: $, Advanced throttle body injection systems capable of transmission control and more. 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. You've got it running and warmed up but now you need to set. (Grease can sometimes do the same thing as a more permanent gasket sealer without making the removal of the air cleaner such a pain.). Is that normal? But another thing to consider is adjusting your target A/F ratio. There are six different acceleration enrichment tables that you can tweak and that may be the way to go. Tps is saying 26% when it at idle. 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. I installed a sniper efi system on my 1969 Camaro. I installed Holley Sniper on three other Mavericks here in Brazil and the problem also exists.I did not make any changes to the parameters, only on Target AFR and the correction on the Idle Speed Curve chart. Also its extremely rich at idle. it will jerk and rpm will go up and down and AFR will be around 20 : 1 or more or less. Both Sniper and trans controller grounds were direct to the battery ground, as they should be. Rpm with 4-8 iac but it still shows red and shuts off randomly at idle and it won't even drive 2 miles without shutting off. Your task will be to find that. I ask because I'm using a PCV valve with my Sniper and have random idle issues as well. However, whenever you start changing things, you can get into a chain reaction. 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. Note: The IAC breather hole is the roughly 1/4-inch triangular hole that sits above and between the secondaries. I've been having problems with my sniper efi just shutting off. 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? Well, it sounds to me like your Sniper is doing its best to reduce your idle. It may take a few tries. It's not necessary to drive it that way. They always responded to my questions with guidance that helped me choose the right system for me. After only running for about 15 minutes or so the system starts to fail stalling the motor. Just add 5 or 10 degrees of advance and see if it doesn't idle better. 63 bomb RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the This may require shortening or lengthening a rod. Ensure there isn't a vacuum leak causing the IAC Position to drop to 0%. Do you have any clue? The Sniper EFI system looks at the closed-loop fuel compensation required to reach your target AFR. 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 have adjusted many settings and eventually mess it up and go back to the original map. I believe that you have this problem solved now with your new inline filter/regulator. That's not the IAC Hold Position, it's a percentage value. Hope this helps! He has walked me through every question Iv. 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. That initial rev is going to be determined by your IAC Park Position. Repeat until that stumble goes away, and then try a bit more throttle. The AFR was pretty consistent around 13. One of them might be faulty. What an amazing site you have here. This value is itself enough to raise the idle a bit. To do this, open up the Initial Startup gauge screen that was used in section 17.0. When you first posted this I had no idea how to respond. 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. My problem is low idle. 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. We offer some tips to help with that. Follow this link to download it for free if you have not already done so. Bottom line ismy first one must have been faulty. Holley documentation and videos didn't work and the $300 I paid for "expert" tuning didn't work either. There is no sense proceeding until your TPS is at zero at key-on. What can I do? Hi Chris thanks in advance for any tips. If the screen shows iac at 0 and you block the hole to find it open what does that mean? 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. is the fuel pressure. Does that make sense to you? I have an entire article on choosing between Sniper and Terminator X throttle body solutions and while Sniper is still a sound choice for some applications, Terminator X (with transmission control) is hands-down the way to go for those who need that. In the Wizard, select the stock cam setting. MAP Sensor. But get that fuel system fixed before going any further. Get On The List for Emails Straight From Our Pro? Then your low idle problem will go away. Sorta similar to a carb having the idle mixture set incorrectly (rich) or the idle speed too low. Thank you for this guide on setting IAC. I've helped folks work through a number of challenges with their Sniper EFI System installations. If you go the other way then you might find that the IAC zero's out when the fans are off. As I said above, you could have a bad IAC, but then again, the IAC might be fine and there's a deeper problem such as RFI noise causing the issue or a vacuum leak that is confusing things. It will need to see it again and again. Cycled the ignition off. If you find that the IAC is more than 8 percent, repeat this process and instead of shooting for 50 RPM below your target make it only 40 RPM below the target idle speed. The very first thing I would do is get ground truth on your timing. And if you're going to go this route I'd recommend that you switch from "Simple" (3 A/F targets, one each for Idle, Cruise, and WOT) and go to the 2-D Table Hey Chris! Unfortunately I did not buy my sniper efi from you. Key, I believe, in this success is solid connections, resistance-free signal and ground paths, and solid RFI rejection. 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. Confirm the placement of all wiring, ensure that the WBO2 sensor is positioned properly, etc. It didnt do this with the carb on it. There's a procedure there I can share with you if you'd like.. 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. A couple of those and you should feel it getting better. :-). Only show this user . Reply Quote. The noise changes sound with the throttle position. If your mixture is too rich, it means there's too much fuel and not enough air. This is more of a bit of a reality check. On startup- cold or hot, I get a 2 second high idle of about 1500 RPM before normal set idle of 750 RPM happens. 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. Enjoy your Sniper! That When I removed the tape and started it again, it was idling at 1400-1500 RPM and sucking a bunch of air through the IAC, even though it showed 0% on the sensors screen (pic attached). It is a common one. Thanks so much for reading! Ultimately, it is about making the pedal softer, particularly at initial throttle opening. Am I missing something. 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. idle counts from 0. However, I have never found that to be the case. First thing I would check This is actually more troubling than the sound you originally described. 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. If I adjust idle screw out to get the tps to zero or even 1% the engine will not idle. I haven't driven it for the 30-40 minutes like the several times it idled at 2200. However, it is a good question so I thought I'd throw a few bits of info out there that I think might help.First, I believe that you may have a basic misunderstanding of what is being referred to sort of generically as AFR. The engine has 14: 1 compression ratio, we can not use gasoline. 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. Others might require 60 RPM. Jump on board now! Shut off car/restart and it's back to idle at The last 2 times have been shorter and one time the high idle was around 1400, this time around 1100. We have shipped quite a few of these to customers in Australia and New Zealand so I know that there is becoming a good following there!We recommend this Inline 10-micron fuel filter to prevent problems like that. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. I drove it a bunch more yesterday afternoon/evening and the same thing happened several times. You advise would be greatly appreciated. Its just at low speeds, not sure if its loading up or leaning out. In the setup, I set the hot idle for 850. Yes, it will talk to you--but not with words. Should I just disable idle timing control? Holley will take a look and tell you you have RFI and wish you good luck in finding it. The fuel pressure regulator in the Sniper is fairly simple and not prone to failure, as far as I know. Find a lower price anywhere and we'll beat it by 5%! (If you do this you will need to reset the -40 degree setting mentioned at the top of this article. First, recognize that the IAC and the TPS are not inter-related in any way. THANK YOU for the "First--Check Your Idle Speed Curve Setting!" hard start about 1/2 throttle from stop it bogs down after 3 or 4 seconds.What I 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. Thanks for any info./insight you can provide, Mark. 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%. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. I will let you know what the results are. Could you provide me with some things to check or some things to adjust? That is the only way to fly. 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. The biggest issue is these problems are intermittent meaning they do not occur all the time. Do you have a PCV on the engine? Then a little faster--until bogs at that level work themselves out. issue. Check fuel pressure too (. Learning to install these is great--you're about to embark on the next great adventure of advanced troubleshooting. Idle was around 1000 mark and iac 0. is train the system or there is actually something wrong.I do love the system at Maybe Holley will add Fuel Prime Multiplier to Terminator X later. Please check your process again and see if you can see very specifically what is not working correctly. I know this is old, but I bought and installed a Sniper kit in 9/18. Usually it wont stay on 0% very long and soon changes to another number like 1 or 2%. Throttle Tip-In puts you in a part of the fuel map where you stay for only milliseconds at a time. Once it decides to come back down, it does so with no issue. 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). I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. I readjusted my IAC, now it's perfect. 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 IAC Pos.% = 0 It is easily solved by installing a four-hole gasket or four-hole spacer (depending on your hood clearance issues.) My guess is a faulty IAC since it is intermittent and I have not done any setup changes. 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. So what--you're never going to drive in minus 40 degrees, right? I'm also having a high idle problem but its different. 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. After doing TPS reset it starts fine but when you give it some gas it hangs at 1500 and will not return to idle. All times are GMT-6. By going into the IAC settings and turning off the Idle Spark control and setting Target Idle to 750 RPM my idle issues are gone, and it now returns to desired idle after cruise. I presume your idle speed table doesn't increase at 200 degrees? I have driven car about 200 miles. The latest was changing the power brake booster.Today I drove it to work and no issues at all. That's what you're seeing. Now that you've installed at least four Snipers it is going to be imperative that you learn to create and read datalogs. The car cruises fine, and if I was to keep idle at 2000rpm the issue wont happen, its only when the car tries to ramp down to idle position.Thank you for your help, any advice would be appreciated.Thank you,Eric, Whenever we see the AFR go to "Heating" that is an indication that the ECU has been reset. The team at EFI pro are some of the best I have ever dealt with when coming to ordering parts or having the knowledge to answer any question you may have. If I block off the iac with tape , I can get it to somewhat idle, but its not consistent.