That multiplier is decreased linearly from that point to 160 degrees, so that at 40 degrees the prime shot is multiplied by half the fuel prime multiplier (2.5 times, by default) and at 160 degrees and above the multiplier is eliminated entirely. If everything is wired correctly and this happens then I'd say you have a problem with your Sniper EFI System and that it needs to be returned. Then I will provide an image of how this variable looks in the software. That helped. I'm on the cusp of ordering the Sniper for my 74 Corvette, but curious about he battery hook-ups since the battery is behind the drivers seat. 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. You can run resistor or non resistor plugs with the 6AL box. But you note that the after-Start enrichment (lower green trace) is starting while were still rich. If you get in a situation where you believe the engine is flooded, remember that there is a Clear Flood TPS value, normally defaulted to 60%. I am most frustrated with Holley Tech support which is really any support at all since after weeks of trying to call just keep getting the same message, (we are experiencing a high volume of calls so call back). Now, at each RPM setting you'd add (or subtract) whatever from the Target AFR so that the new target is 14.0:1. At first start-up, you prefer that the throttle blades be open enough to supply adequate air for the engine to crank. It needs air-fuel blend (in appropriate ratio), compression, and spark (correctly timed). 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. What do I need to do to rectify this issue? i.e., 5x at -40 and 0 at 160. Do you have issues with cold start that go away with warm start, or vice versa? I plan on converting to efi this coming spring. You're not running your EFI system without a gauge are you? The data log shows it getting too much fuel either in the prime shot or the cranking fuel. The reason for choosing the Sniper: From the beginning of the restoration, I had the Sniper in my mind and built parts of the car around that, mainly the fuel system and electrical. Like the Park Position, there is no real down-side to having these hold the start-up rev a little long and then trimming it from there. Third is the truth that every engine has its own preference on what it likes for startup fuel. Cheers Darren. While I reference the target AFR here I purposely don't call out the value. So you be the judge. Is a tremendous volume of fuel sprayed into just one barrel? Tune the cranking fuel in the following locations: Using the Handheld Tuning > Advanced > Advanced Fuel > Cranking Fuel, Using the Software Fuel ICF (Fuel Injector Icon) > Startup Enrichment > Cranking Fuel. Increase that to 15 to start. My problem is that it starts and stalls instantly then acts flooded. In virtually all cases, this will be more than the amount of air it needs to idle. In fact, they may be terrible values when applied to your engine. Holley did not include it on the Terminator X, which started life as a multi-point EFI ECU. Is this normal? shut truck off. If it dies or drops more than 50-75 RPM the throttle is closed too far. Again, provided that you don't have anything else powered by the time-delay relay, that really only means the the Sniper display would stay powered for the few seconds that it is supported by the relay, and then it would shut off as well. 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. Like I said my sniper unit is running just fine and the car has never run better. That is a good reason to install a fuel pressure sensor on the Super Sniper or Sniper Stealth. Start by increasing your TPS and MAP ROC blanking values. Price Point: $$$. Your advice would be appreciated. How efficient is your engine startup? But never ever forget there is a second learning going on--your own. Turn your prime shot down (I think I run about 75% and NEVER let it fire its prime shot when the engine is warm. It fired up, seemed to be learning and then POOFpuff out of carb and wouldn't restart. The xflow instructions state it needs 60 psi. That amount of air is determined by the IAC Park Position. When a wide band sensor is (DAMAGED) it almost always reads dead lean. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! Pin 85: To Ground I created logs in the past but never knew what I should be seeing and how to make the specific tweaks. Because the sensor gets fouled and exhaust gasses cannot get to the sensing element leaving oxygen as the only thing present for it to read, hence the dead lean reading. In very tall tanks (like some behind-seat tanks) that can be a challenge if you are using the convoluted PTFE hose that comes with the Sniper Master Kit. My fuel pump keeps running when the ignition is on but the motor is not. 10.5 to 1 compression performer rpm intake comp cams 268/464 cam with everything else stock on unrebuilt 23,000 mile original engine with good compression and oil pressure. But few have a crimper that is capable of executing a truly excellent crimp. Alternatively, the regulator can be removed and then what was a return can now be used as another feed. It's almost impossible to hurt an engine with no load on it. All seemed well with the setup and going through the handheld. I really want to go EFI this year. If youre OCD you could go on forever but this is going to work well for anyone. Bolt-on carburetor style EFI for your classic car or truck. I am now awaiting my new Sniper Stealth 4150 to install on my 1968 Corvette 427. Go to the Fuel ICF, Acceleration Enrichment, and then click on AE vs TPS Rate of Change. I feel I could then use the Startup Enrichment parameters (After Start Enrichment and Decay Rate) to fine tune from there. Does pressing the throttle slightly allow the engine to start. That's a spread of 200 degrees so half of that would be 100 degrees. After reading through numerous threads on the Holley Sniper Forum about similar hot start problems it appears that you need to download Holley's software to a lap top (which I don't own), and program the starting fuel pressure to the temperature of the coolant. Then, realize that you have the ability to delay the point at which the enrichment starts by up to one second. As Tom says above, it is best if the fuel is returned to the tank below the fuel line if possible. Exactly. 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 Unfortunately, the only way to do this is with the Sniper Software. 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. Price Point: $$$. (Plus, it's easy to do---see this article.) Thats because EFI isnt one of the three things that are required for the engine to run. You mentioned its use in # 9 of the top 10 Sniper EFI installation tips. 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. Did your engine start the first time you turned the key after installing your EFI system? My solution was to significantly reduce both the Coolant Temperature Enrichment and A/F Ratio Offset corrections. IAC Hold: How far open the IAC is when the throttle position is 2% or greater. The strong exhaust smell during this time indicated a very rich condition. And the smell is just about gone. Fyi both fuel pump rocker switches have momentary primes. Back to holley.com . It drains the battery almost dead then will fire up. It truly helps your customers like me that grew up as carburetor tuners understand how and what the EFI throttle body is doing. Or do as I do? Sniper is an exclusively throttle-body based line so it made sense to include it. Digital electronics like clean stable voltage. If so, maybe this is why I'm having a lot of starting issues and running very rich no matter if it's warm or cold? Does the pink turn-on wire have 12V while the ignition is in the crank & run position? Lets try 75% on the fuel prime. If the fuel pressure is a little low don't worry about that. 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. That delay is called After-Start Holdoff. 03-14-2018, 07:03 PM. This is a bit tricky. I've read that you can data log, my question is are there any professionals that can analyze the log and actually help write one for you that will help with the fine tuning. I Had a holley sniper on this car with no issues whatsover. I see recommended plugs are resistor type. Nor can I really recommend that you split it as I have. Capability Range: Moderate That's not the case here is it? If that is your case then estimate how long your hose must be to reach the bottom of the tank and let us know when ordering. Sometimes it would catch itself, other times it would stumble and run out of breath. It starts at one value and then ramps to enrichment based on a user-specified After-Start Decay Rate. Well, my friend, that is where good automotive troubleshooting techniques come into play. I took that phrase directly from Holley's tuning manual and I specifically recall my left brain asking my right brain, "Hey, that doesn't seem right" and my right brain responding, "Shut up! 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. Best Overall. It seems to be going threw gas faster then it should. Thanks. I'm glad this approach worked for you. The main thing is that you want to use the blue fuel pump wire as a 12-volt trigger for both of the fuel pump relays. :-). Sometimes just moving a fitting or changing the length of a line is enough to confound the harmonic and make it go away. If not, then the orientation of your O2 sensor is not your problem. Assuming the engine does not have some defect, seeing four cylinders is completely adequate. This is extremely unreliable afrer warm. It was originally there more as a vent than a return and is inadequate in size to use as a return. Stay up to date with the latest releases, events, promotions and more. I know it's only 2 feet but ever inch counts. EFI Systems based on Holley's world-class Dominator and HP ECU's. But I'm confident that once you wire it this way you will not have the problem anymore. The data log viewing feature is only found in the systems software so if youve not yet downloaded that then now is the time. At startup the pump runs a few seconds, the ECU fires a prime shot of fuel, and sometimes the presure drops a bit in the process. My question is if both of my fuel pumps are wired from relays to my rocker panel where does the blue fuel pump prime wire connect or would you just not use it altogether. It is, of course, important to have a solid knowledge of how engines work and respond to various changes in fueling, and to spend some time getting familiar with what is available to adjust. Default values on these are 150% and 5, respectively. My setup requires too much pedal pressure both starting and running. And 10 micron filter between the pump and throttle body. Engines require three things to run. That added fuel is called after-start enrichment. Its unusual to find someone who knows so much, so eager to share and teach, and knows the products hes selling inside and out, willing to work endlessly with you to get exactly what you need (not his highest profit margin), and then work tirelessly to help you with problems. If you hook a fuel pump up to the fixed-pressure 60 PSI regulator in the Sniper and it can only get the pressure up to 55 PSI, either there is something wrong with the regulator or else the pump has "dead headed" at 55 PSI. 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