If you turn the ignition off and back on, & crank it, it will start & die again. "I've edited the article with a note about the difference. Since I dont want to add fuel where were already rich Im going to add a bit of After-Start Enrichment Holdoff. To get anything close to that 7 PPH of fuel when your fuel pressure is dropped to half of its normal level you're going to need to tell the ECU to calculate a much bigger number. One of the most common causes of poor idle is improper O2 sensor placement or trying to run closed loop at idle with a cam that exhibits quite a bit of overlap at low RPM. Enjoy! injection systems capable of Yes, I have fuel pressure. If you turn the ignition off and back on, & crank it, it will start & die again. Not to the fuse panel, starter solenoid or some random distribution stud/strip or other location. Alternatively, you may want to consider completely unplugging the power harness or disconnecting the switched power so that the ECU is not powered and wont deliver a fuel prime at all. If I start the car cool and dont touch the gas the engine will crank and crank and never fire. (Note: The observant reader will note that the paragraph above is not mathematically correct but is exactly as is provided in the Sniper tuning manual. Would it start & quit like that if the switched wire wasnt working? Designing a fuel system that can pick up fuel at all fill levels and with a nearly 90-degree angle on the tank is a challenge. Thanks, Steve! Troubleshooting - engine starts and stalls Troubleshooting - engine starts and stalls Bill Tichenor 12/02/2009 10 min read Share Carburetor Installation and Tuning Video carburetor tuning and adjustments video Footage taken from Holley Carburetor Installation & Tuning DVD author Bill Tichenor 358 Posts An Article About First, it is fake news that EFI doesn't like big cams. The Ordering process was so easy and non-painful. The resulting O2 sensor failure is damaged not defective. What is important is that you understand what happens at this point. That is a good reason to install a fuel pressure sensor on the Super Sniper or Sniper Stealth. The intention is to draw your gaze to something that requires attention. Am i doing the right thing? Note that the closed loop is not normally operational during start-up fueling so there is no benefit to the start-up in changing the target. Disable the tach sweep on your ignition box. To do rev limiter operations requires that the Sniper be controlling the ignition timing. So here's how I'd do it:Pin 86: To your ignition switch (12 volts) Installed my Sniper, went through the startup procedure. Where do I start looking for the solution? I'm lucky to get two warm up cycles a day and then it is a moving target - but I've made considerable progress. That delay is called After-Start Holdoff. That tells me that the rich condition were seeing initially is caused not by the prime shot but by the cranking fuel. Lets try 75% on the fuel prime. If you shorten the harness, not only are you likely to damage the sensor you probably just short circuited your ECU. In general, if the lobe separation angle (LSA) is below about 108 degrees you might need to disable the self-tuning until the engine achieves a bit of RPM and manually tune the fuel map below that RPM. Is the sniper compatible with my distributor? Ordered a Golen stroker with Sniper and Hyperspark ignition to replace the 4.2 in my 89. In a nutshell, you do the following:1. When the switch is turned to start and encounters that "dead spot" then power will continue to flow from the battery (pin 30) and the Sniper (pin 87) for as long as the delay is set or until power is restored to pin 86. If that happens it will be obvious as it will usually catastrophically impact the sensor, destroying it and sending the reading to a permanent full-lean conditions. Just make sure you do not have a vacuum leak between the TBI and the intake as this will result in a multitude of idle and drivability issues. O2 Sensor Mounting: The O2 needs to be mounted 6-8 after the merge in the header collector.Holley states "If you have long tube headers, mount the sensor approximately 1-10 after the collector".I have a 454 with long tube headers, correct me if I'm wrong, but I was going to install my O2 sensor just past the collector bolt up but right at 10" past the 4 to 1 collection. Is a tremendous volume of fuel sprayed in all barrels? Beyond that you're going to have to get Holley tech support involved. Hard to answer. Thanks Chris, keep up the good work. Any suggestions? Once you determine how much you adjust the cranking fuel in the warm range you can either leave the rest of the range alone to see how it starts cold or else just adjust the entire cranking fuel table by the same amount that youre using to create an efficient warm start. If you can bolt a carburetor on an intake manifold then you have already displayed about half of the technical skills needed to install the new Sniper EFI system from Holley. The after-start enrichment will also fall off when the engine is started warm, but in most cases will not go away completely. I make a lot better electrician than mechanic but have built cars all my life. So now youre left with tuning the Fuel Prime Multiplier. To be 100% honest I was having an issue prior and flooded it. Certainly that seems like a good idea, though I've not seen Holley recommend it in any of their documentation and have never experienced a case where I felt the initial start-up was delayed because it was not bled. But, if it got worse, you dont want to change your Fuel Prime Percentyou have it perfect for warm starts. Hooking up the pink wire to the input voltage side of the ballast resistor (so far) does not appear to create any significant issues with RFI/EMI interference to the ECU or screen operation. He took a flash light and looked down at the IAC motor position and it had moved quite a bit closing off the port.Now I had to try this and of course my results were not so lucky. Sure enough the pink wire DID NOT have voltage when cranking. No timing control. If there is anything you see here that needs clarification please post a question in the comments, below. Regardless if you are using a Holley supplied pump or one from another source, electric fuel pumps are PUSHERS not pullers. Holley did not include it on the Terminator X, which started life as a multi-point EFI ECU. We offer two potential solutions. Maybe I am missing something here. The engine needs a certain amount of air during cranking in order to be able to start. Free ground shipping regardless of order size! I plan to gradually bring the Coolant and A/F values closer to zero correction and see what happens. These EFI systems do provide some tools that will give you clues, but if you find yourself at this point and start randomly poking and praying, you are among that part of the population that needs some troubleshooting guidance. Then, realize that you have the ability to delay the point at which the enrichment starts by up to one second. Then, click on AE vs MAP Rate of Change and change that to 15 as well. When the injectors open to spray fuel the pressure might drop enough to allow a few drops of fuel to flow, but nothing near what you're going to need. idles good, runs amazing. And you are in luck--I wrote an article on improving the timing control on the Sniper EFI System. 12/02/2009. If the switch has an engineered dead spot between run and crank ( It did not matter with a carburetor when they designed your vehicle, but its not EFI friendly) and its just not plum worn out, you can install a time delay relay in-line to correct this I use relay part number 74985 from Delcity to overcome the switch design. You just have to go one direction and see if things improve or not. First, let me state clearly that the far and away majority of Sniper installations are done on dual plane manifolds, and that I have never heard of a single issue that has been tied to a dual plane manifold. Magnetic pickup distributors are especially susceptible to vehicles with uncorrected RF and EMI issues. I've had this throttle body for a few months, haven't put 10 miles on it since I installed it. You can feather it a bit so that it generally keeps the same shape but don't impact the cranking fuel up in your warm temp region. Question is, do I just plug what was the return at the throttle body? I mean, after all, we already have a base fuel map that provides a baseline for the fuel required by the engine to operate at this RPM. Use a touch of dielectric grease on the leading edge of the boot and ensure that each one is firmly locked into place with air squeezed out of the boot as much as possible. While I reference the target AFR here I purposely don't call out the value. It starts fairly well. Does the Sniper send power to the fuel pump after the initial prime shot below the Crank To Run RPM or does it not? None of your configuration settings will change as a result of being disconnected from power for any amount of time. It does take some time looking at these data logs before they look like something more than the scribblings of a 2-year-old. Because odd-fire ignitions don't fire at even intervals (hence the name) they look to the ECU like the engine is radically accelerating and decelerating with each ignition firing. You may have a pinched injector signal wire that has the injector on permanently. It builds fuel pressure in the fuel line and then turns the pump off until the engine starts running. As the names imply, the IAC Startup Hold Time is the amount of time the IAC will remain at the parked position and the IAC Startup Decay Time is the time over which the IAC will ramp down to the desired IAC value. My problem is that it starts and stalls instantly then acts flooded. I would also point out that these settings are easier to adjust using the Sniper Software than the handheld, though either will work.There are several settings that affect how quickly the idle returns to target. How efficient is your engine startup? Not much I can add to that. Read the instructions and Follow them. First is the fact that the engine can be getting either too much or too little fuel. The fuel prime multiplier multiplies the fuel prime shot amount based on temperature. This is the crank-to-run RPM. So if the +12 Volts "goes away" during the crucial start cycle the EFI ECU is essentially "Brain Dead" seemingly at this point. Beyond that you can turn your cranking fuel down. Back to holley.com . Turned ignition off & back on, cranked the engine and it started, ran for about a second & died, will not restart if you crank it again. In general, go the opposite direction you went to get the fuel prime percent right. Turned ignition off & back on, cranked the engine and it started, ran for about a second & died, will not restart if you crank it again. Thanks. Directly to the BATTERY!!! is setting themselves up for unnecessary frustration. Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. Fix that.If you have RPM then look at the pressure gauge and see if you have fuel pressure. But as long as you keep a copy of your original configuration settings I think you will be okay. Love the example at the end. This is most easily done using the blue fuel pump wire. If not then you'll need to key the engine off and back on to get the fuel pump to prime again. Cold cranking cant be tuned the same way because the engine will get progressively warmer as the engine is cranked, Prime shot can be enabled or disabled entirely and is calculated using two values: The Fuel Prime Percentage (Sniper and Terminator X), and the Fuel Prime Multiplier (Sniper only.) I am having a 2 572 BBC being built for my boat. Not some generic piece as some have speculated. You have that where you want it. Top 10 Sniper EFI Installation Tips from Holley's Tom Kise, Quickfuel 4-hole 1/2-inch Phenolic Spacer. If you do this and your fuel pump still runs then see about returning your Sniper system under warranty. This is why most OEM EFI pumps are in the tank. Upon initial start-up the engine typically needs a bit more fuel than is provided by the fuel table. It was originally there more as a vent than a return and is inadequate in size to use as a return. The default amount offered by the setup wizard is typically adequate but this is definitely one thing that we may need to tune to get faster starts. But I strongly suspect that is not the case. Any help with this would be greatly appreciated.Gary. Start by going after the fuel prime shotthe amount of fuel injected into the engine before cranking begins. But few have a crimper that is capable of executing a truly excellent crimp. Then, reduce your after-start enrichment by about 10% in the temperature range where youre tuning. Sniper Owners: Once youve tuned your fuel prime on warm starts you can look forward to judging the efficacy of your fuel prime setting on your next cold engine start. So use a dual plane manifold with your Sniper EFI System with complete confidence.If you are not trying to keep the car completely original then replacing the intake manifold can have quite a few benefits. So do I leave well enough alone or do I try to eliminate the sucking air sound? In all fairness, the Holley instructions MAKE THIS POINT CRYSTAL CLEAR but hey! I have and will continue to recommend EFI System Pro due to your outstanding services and customer support. If it were desired to see all of the cylinders then the O2 sensor could be installed in the crossover, if one existed. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! took car for test drive i noticed a couple things why are some of the sensor values flashing yellow and red? Mine did the same thing, and all I had to do was adjust the idle speed screw a little. FE 390 that currently has a Pertronix distributor with the Ignitor 2 module. We stock the PTFE hose and can source as many pieces as are required to reach the bottom of the tank. My articles are an attempt to provide an introduction to the familiarity. Then draw the power for the relay directly from the battery. Good point. Go Gators. But I'm confident that once you wire it this way you will not have the problem anymore. Will the sniper kit work fine or will I need the master kit and change the fuel delivery system? Super helpful. Thanks! 2. Holley's Dominator and I trust you'll be using this new knowledge to speed up cold starts up there in Alaska. Chevy 350, rocker cam, mild cam. ), I have the sniper efi system with the holley retro-fit in tank electric fuel pump. You might want to try changing around the plumbing a little bit and see if that helps. Im not looking for timing control just upgrade to EFI. Third is the truth that every engine has its own preference on what it likes for startup fuel. I call this the Happy Dance moment. I am in the middle of plumbing my new sniper throttle body system. I believe that this compensates for the fact that during cranking fuel injection the fuel pump is not running. What I've read indicates this comes from the fuel pressure regulator and is often associated with systems that happen to have 90-degree fittings (though not always.) Unfortunately, I know NOTHING about throttle stops. You are on the right track!Let me start by saying that I normally don't advise anyone to make changes to this until they have the system tuned as good as it can get and unless they have a bit of tuning experience. Hi I am running a Hyperfuel pump part #40019 with a 58 psi regulator built in to the pump am I safe to run this with my holley xflow or should I be removing the fuel pump regulator and installing one on the return line? Featured Products Sniper EFI $7.07 - $2,457.95 471 Products View Parts author Staff Writer 1711 Posts An Article About Video tech Sniper EFI Videos Sniper EFI Tech Sniper EFI sniper Installation Fuel must also be added to start the engine. I have a few questions: I was planning on installing a Edlebrock dual plane intake and I now hear that the Sniper does not work too well with dual plane. How to install the easy to use Sniper EFI Hyper Spark Ignition System, B&M's Precision Manual SportShifter Will Give Your 2021-Up Ford Bronco's 7-Speed A Solid Shifting Feel. Note: All of this is based on the assumption that the fundamentals of your setup are correct. Runs, then dies. Let me know what works for you! 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