Is there away to program the ecu to compensate for this at start up. Solving Holley Sniper High Idle Issues - EFISystemPro.com 63 bomb your IAC is at zero. carburetor setup, but it does blow when I can't jump on the highway like I use Definitely would have went with you guys. Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to I would start by datalogging the situation and seeing exactly what your learn table looks like in the area immediately around the tip-in. Properly configured, the Sniper does a fantastic job of responding to the transition from Park to Drive. I never had a problem with this. I have driven a stand-alone transmission controller for the 4L60E in my (then) Sniper-equipped '95 GMC pickup using the Sniper TPS with complete success. Any help would b great. 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. If your mixture is too rich, it means there's too much fuel and not enough air. I have an entirely separate article on Solving RF Intereference Issues. At that point, with 90 PSI of fuel, the ECU can't turn the duty cycle down low enough to idle properly. That initial rev is going to be determined by your IAC Park Position. 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 have an adapter on the manifold for squarebore to spreadbore and then a phenolic spacer. Do I have to hook up sniper ac wire to relay or should iac pick up idle? I'm so glad you found this helpful--that makes my day!Don't get too concerned about the specific learn percentage. I have a set of 8.8 Accel Rfi suppression wires on it. 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). In the warm state IAC adjusted to a position of 2 to 10%. From herethe cycle continues and I am Fought a high idle issue until I changed your idle speed curve fix along with dropping the IAC hold to 10%. The Sniper EFI remote IAC (Idle Air Control) and plug is designed to gain installation clearance on some Sniper EFI 2x4 installations. A couple of those and you should feel it getting better. :-DStill, I hate to leave someone hanging so I'll try to help. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds Give us a hand! 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. Getting the throttle blades and IAC to work together will keep your fuel injected hot rod running smooth and predictable. Using the handheld, navigate to Tuning > Basic > Basic Idle and ensure your target idle speed is set to the RPM you desire. No, the idle speed curve setting isn't something that you normally worry about--and especially not down at minus 40 degrees farenheit. This page was generated at 12:25 AM. Holley Sniper EFI Self-Tuning Master Kit - Black Ceramic Finish That is not the way to go. When you open your IAC to 30% you are naturally going to have a high idle condition. 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. Thanks for the information you have provided on this site. Do you have a PCV on the engine? First--besides the fact that it's not represented on the display, it is not even a parameter that you can datalog. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. Eventually the IAC will drop back to zero, I'll readjust it to 850 RPM & 2-9%, and then watch it steadily climb again. 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. Is that normal? Since a key cycle resets it to 0 and out to 30 or wherever 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. no timing control. Any suggestions would be appreciated. Well, it turns out that with the current firmware this throws the IAC control into a bit of confusion. Also when ac kicks on it will idle down and stall. If you do find you have RFI issues then I've written an article on solving RFI problems. Turning it off and back on would reset it, and then it would work as advertised for a while. Sometimes an engine can produce enough vacuum to pull the secondaries open slightly. 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. I readjusted my IAC, now it's perfect. have the system learn the higher speeds? Except at idle. Interesting question. That is the IAC hold position. Any suggestions? I have changed my roc/tps to 7 from 15 but that only took me out of learn mode. Im thinking a faulty TPS. I can have it working fine (5% to 10% at target idle at operating temp.) If you use your handheld to go here: We have never had that problem with any of the units that we have shipped. It sounds like you need a bit more of a fuel squirt on acceleration, Brett. I'm wonder if the iac can cause this. Then do it just a bit faster--just enough for it to bog a bit. 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. The first 250-300 miles were amazing as the Sniper EFI worked flawlessly. I have been reading these posts and have learned a lot. Kind of cuts into forum time. I straightened that out, got it running and that's where it goes downhill. I have now determined with the TPS the noise correlates with the opening of the secondary butterflies. Incorrect connections will result in excessive resistance. The motor has 376hp at flywheel and the car is a stick shift. Ive played with the timing on this thing multiple times.Car was fullly restored last year. 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. There are six different acceleration enrichment tables that you can tweak and that may be the way to go. If I read it correctly, the solution from the other thread seemed to fix a constant 300 or so RPM increase. 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). I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. Have you checked your fuel filter and made sure it's not plugged?If both of these are okay you're going to have to find a way to monitor your fuel pressure while under load. 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. If you have any questions about the car/setup let me know. It will need to see it again and again. 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. We're having trouble with a Ford Maverick 302 V8, using ethanol. RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the The distributor was loose. Capability Range: Moderate I started with right after I first adjusted for 2% IAC and took pics about every 30 seconds over about 2 minutes. If I'm driving along and pull up to a light and leave it in gear it idles just fine but it seems not to be able to compensate if I put it in neutral and then back and drive. 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. Then you can take a close look at the IAC and see if it is opening. Holley Sniper IAC | Chevy Nova Forum 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. I'd suggest that you assume everything the previous owner did was wrong until you can prove that it was done correctly. If your RPM is 2000, your TPS is 0, and your IAC is not closing, then there is some problem. We're never going to fill up your email box with nonsense. What would cause the idle to faulter like that? It could be a problem with the power/ground for the Sniper but much more commonly this is a result of too much RFI. Clearly, something is changing. 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. Using a Snap-on variable timing light so this is why I say timing is perfect. Capability Range: Professional I have verified that there are no vacuum leaks, not to mention the car runs to good to have a vacuum leak bad enough to make this noise. 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. That is the first thing you must find. 1. You have to remove all hoses in order to debug the problem. When the lambda is 1.0, the displayed AFR is 14.7;1 REGARDLESS OF THE FUEL. Any idea's? I will turn it up some more.Is this something that the ECU will learn? Fortunately, these are much easier to solve. I've been having problems with my sniper efi just shutting off. I'd say make sure you buy from someone who can give you good after-purchase help (hint!) Add To Cart. 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. 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. itself out and hold idleeventually stalling. :-). Everything was working perfectly and I shut off the engine. I can adjust at 160deg, but my fans turn on at 180deg. Your issues are likely related to one of these two things. 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'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. If I put the truck in park it comes down to idle. Well you were right air was entering from another source. 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. Does anyone have photos of this additional return spring they installed? Simply turn the idle speed screw on the linkage in until the throttle plates open enough for the idle to increase. The problem I experience is that after driving for about 10-15 minutes, the car starts idle to high.