:-) Just don't let the parts go flying. I will turn it up some more.Is this something that the ECU will learn? They are prone to be inaccurate. Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to The Street/Strip and race cam setups tend to be too rich initially. Hello 2. Just add 5 or 10 degrees of advance and see if it doesn't idle better. I appreciate everything you are saying. Bryan McTaggart 02/28/2023 news It sounds like you need a bit more of a fuel squirt on acceleration, Brett. Generally, one of two things: a stuck throttle or noise on the TPS signal. Learning to install these is great--you're about to embark on the next great adventure of advanced troubleshooting. Tried that and it didn't work? Key, I believe, in this success is solid connections, resistance-free signal and ground paths, and solid RFI rejection. If so remove it. 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. At 0% it shouldn't be sucking any air through that port, correct? the gas it catches itself and runs fine at slower speeds. It shuts off when coming to a stop sign, at any cruising speed and romdomly at idle in park but never when excelerating. Copyright 2022 Holley Performance Products, Inc. All right reserved. All of the wiring exits below the rear fuel injector cover, for a completely stealth installation. No matter what do, my idle will not drop below 1350-1400 RPM when the engine warms. Idle quality is great, RPM is good, sometimes IAC is now between 2 and 5 exactly where it should be. THANK YOU for the "First--Check Your Idle Speed Curve Setting!" That 60% (which is configurable) is known as the Clear Flood TPS. Idle was around 1000 mark and iac 0. The hold position is part of the response that keeps the car from dying when you come off the throttle. I've helped folks work through a number of challenges with their Sniper EFI System installations. Earl's Mechanical Fuel Pressure GaugeI could use that for a quick troubleshooting for 1/3rd the cost of the Holley one. A simple remove & clean will remedy this . IAC Pos.% = 0 This curve runs fom -40 degrees to 260 degrees, and gradually reduces the RPM along that range. Fought a high idle issue until I changed your idle speed curve fix along with dropping the IAC hold to 10%. I have not heard of this. I' m going to put the 3 rd new pump this coming friday. you have it set. Super helpful and knowledgeable. Any idea's? Just getting it to act right at startup is a struggle. The link above includes the option to buy a -6 AN Its timed to 36 degrees. Once engine is warmed up been driving for awhile. 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 also noted that after some time, I could change those values as I saw fit. I keep doing that with the same result. Enjoy! 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. Or is there something else I should Even though you think your timing is perfect I'd suggest you try cranking about 5-10 degrees of advance into the distributor and just see if that doesn't work better for you.Remember this: adjustable timing pointers go out of adjustment and harmonic balancers slip. Price Point: $, Advanced throttle body injection systems capable of transmission control and more. Thanks. It is easily solved by installing a four-hole gasket or four-hole spacer (depending on your hood clearance issues.) If the ECU has not spent some significant time learning yet, I'd recommend going back through the setup wizard and getting everything back to default. No, the idle speed curve setting isn't something that you normally worry about--and especially not down at minus 40 degrees farenheit. But I am having troubles.When stepping on the accelerator slightly with idling, it will be 2000 RPM all the time. I think that this time around you will find that it starts and idles really well and only gets better from there. When I covered the IAC with my finger, the RPM dropped so low it stalled. Hello Chris. You could install the Holley Dual-Sync Distributor and let the Sniper control your timing. 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 can have it working fine (5% to 10% at target idle at operating temp.) The first thing I'd do is check your fuel pressure with a gauge like this. Turned it off and on again. If this is the case then some adjustment of the linkage or the butterfly plates themselves is necessary. So try changing your IAC hold value slightly:Tuning : Advanced : Adv. If either of these is not the case it must be remedied.After you have done this then you might want to involve Holley Tech Support about the TPS, or it may be easier/faster just to visit the local auto parts store and pick up a new TPS and install it. Thank you for any advice. You will have to do this until the TPS stays at 0% when the throttle is closed. Thank you chris for for getting back to me on this matter.I'm using russell hi pressure gas line to feed the gas up to the sniper and using the stock steel gas line that use to be the feed line for the carb to return the gas to the tank. I've been having problems with my sniper efi just shutting off. Thanks, That is an strange situation. You might have a bad O2 sensor, really bad exhaust leak or a problem with the ECU. idle counts from 0. There are six different acceleration enrichment tables that you can tweak and that may be the way to go. I had a customer who struggled to understand that. Please check your process again and see if you can see very specifically what is not working correctly. Or ?I have put a fuel pressure gauge right at the inlet of the sniper and it is reading 60-64 psi. 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. Give that a go and see if you don't make some progress! I have a 406SBC that does most everything right with this sniper setup. AGAIN This is Intermittent meaning on a recent trip I stopped 3 times and issued occurred once. (Plus they it just looks way cool in your engine compartment!) I had that problem, right out of the box it would not power up, sent it back in, had defective hand held. The very first thing I would do is get ground truth on your timing. What I would recommend is getting somewhere that you can spend a significant amount of time doing starts. I have one customer who is having some similar issues and his AFR is down at 9.6:1 when it won't start. Based on your situation above as well as some of other experiences, I recognized that I needed to improve my tuning procedures above to better explain what steps to take if that 10-step process doesn't completely solve the problem. I'd say make sure you buy from someone who can give you good after-purchase help (hint!) Just wondered if you've ever run across a system not powering up? 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. First, recognize that the IAC and the TPS are not inter-related in any way. Now it registers zero and I have good idle but it will not register until it hits 60 and up. Could be a bad IAC motor, replace it and see if that solves the problem. Were the additional load a simple step function it would be challenge enough for the ECU to gracefully increase the engine speed without overshooting. 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 Thank you in advance for your help and providing us rookies with your 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. And Earl's makes a fantastic little 100 PSI gauge. I have adjusted many settings and eventually mess it up and go back to the original map. Since it is unlikely that anything else changed it is most likely the IAC is problematic or the butterflies are not shut all the way. However, I have what I will call a whistle at a throttle position on 35 - 50. Those don't impact the way the engine runs and can cause the whistle sound you describe. If it is then something is commanding the ECU to open the IAC. nothing stays steady. 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. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds I looking for your expert opinion. Also when ac kicks on it will idle down and stall. EFI System Pro had everything I needed for my EFI upgrade. I have an adapter on the manifold for squarebore to spreadbore and then a phenolic spacer. 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. 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! Its rare that you find someone that genuinely wants to help and see something work good, the information I have received from this page and Chris himself is top notch.1969 Dart GT 340 with a Holley Sniper, I purchased the Holley sniper from jegs wish I knew you sold them put on my truck got the IAC set haven't checked the -40 idle setting yet my problem is my headers are glowing red called Holley I think I got the worst person seemed to care less Afr is set at 12.8 for idle only thing I have changed I don't smell any fumes at idle someone said I could change the coolant temp enrichment but I don't know if it is rich or lean I figured since no smell it is lean any ideas would be appreciated thanks i have a fuel psi gauge reads 60 psi don't wanna melt my motor did not glow with a carburetor. If you use your handheld to go here: I am Japanese who attached Sniper EFI. Cheers Darren. Thanks for sharing that, Jason--great info! Those little 1/8 NPT gauges are pretty inexpensive and generally pretty easy to find locally.If you confirm that the pressure is indeed 90 PSI you could pull the fuel pressure regulator apart and check it. I will try the other stuff when I get off work. I have certainly seen this before on other fuel injected vehicles when hot. Thanks for all your help Chris! I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. 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. I'm happy to walk you through what is required. The RPM would increase for no reason. Your task will be to find that. Physially manipulating the linkage by hand will generally reveal if you have a sticking linkage that is preventing the TPS from returning from zero. Genuine Walbro fuel pumps are virtually bullet-proof. 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. Put a strong piece of tape over the IAC breather hole--duct tape or something that couldn't possibly be sucked into the throttle body. Usually it wont stay on 0% very long and soon changes to another number like 1 or 2%. Has a good size camshaft cant find any vacuum leaks. Part# 538-13. RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the OK, I did the baseline idle speed screw setting. Now, in my lifetime of experience with Holley ECU's that seems unlikely, but this guy sounded really sharp and had nothing to gain by convincing me of his dilemma. 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. 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. To be honest, you sound like an ideal candidate for Sniper ECU ignition timing control. What should I be looking at to calm this down? Be sure to re-enable it once you get your idle tuned. Once it decides to come back down, it does so with no issue. 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 you do find you have RFI issues then I've written an .