holley sniper starts and dies

Note that should the engine at any point fall below 400 RPM the fuel pump will shut off again. It is going on a 1966 coronet with 1964 413 wedge. If you turn the ignition off and back on, & crank it, it will start & die again. Bill Tichenor. (Plus, it's easy to do---see this article.) Did you hear the fuel pump run at key-on? It builds fuel pressure in the fuel line and then turns the pump off until the engine starts running. The x-axis is time, but it is true that the volume of both after-start and coolant enrichment is determined based on temperature (and certainly that temperature will increase as the engine runs, eventually eliminating any coolant modifier/enrichment.) Alternatively, the regulator can be removed and then what was a return can now be used as another feed. He gave no details, is this an option and how would one go about this. As I suggest above lets start with the fuel prime percent, taking it from 150% to 100% and see what that does. Sounds like it is "only" burning through the initial priming shot. And I've helped my share of folks with fuel pumps in empty gas tanks. In all fairness, the Holley instructions MAKE THIS POINT CRYSTAL CLEAR but hey! Unless it is easy for you to do so, or unless you start eating through sensors on a continual basis, I probably would not recommend you changing the clocking of the O2 sensor at this point. 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. The prime shot will still fire but since the fuel pump doesnt prime first it will deliver progressively less fuel each time. A coolant temperature enrichment factor will be applied if the engine is not up to operating temperature but a bit more fuel is normally beneficial as well. and set 3.) Unfortunately, the only way to do this is with the Sniper Software. You have that where you want it. 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. Another great dissertation. Price Point: $$$. That amount of air is determined by the IAC Park Position. Fuel Prime Multiplier is primarily a benefit to throttle-body based EFI systems. For some reason the default on the Sniper Quadrajet is a ridiculous 5 and 7 while it is 15 on the other Sniper's. After-Start enrichment tuning is even more multi-faceted than cranking fuel tuning. I really would like to replace the intake gaskets. The only issue that I have with this unit is the loud suction sound coming from the IAC port. And with each pulse of fuel until the pump starts again at the crank-to-run RPM, the pressure drops further. Enjoy! The default for these systems is 400 RPM. Where do I start looking for the solution? :-), Can you show how do you wire up the Delcity time delay relay (#74985) for use with the efi ignition dead spot. 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. You also need to properly phase the rotor. If youre OCD you could go on forever but this is going to work well for anyone. Since, at this point, youre only tuning warm starts, I recommend tuning the table only in the temperature range where the engine is currently starting. Thanks. I'm glad that worked for you! Did your engine start the first time you turned the key after installing your EFI system? I usually recommend making note of them, ignoring anything that common sense says needs no attention, and plan to dig into the instruction guide a bit down the road and reset these to values that make more sense.Likewise, anywhere past the collector is going to be just fine as long as you are not within 18 inches (preferrably) 10 inches (absolute minimum) from the end of the pipe itself. O2 Sensor Mounting: The O2 needs to be mounted 6-8 after the merge in the header collector. Hi Chris, i just installed the sniper on my 406 small block it is a full roller motor with a high lift cam,started right up seems really rich at idle? In my experience startup fuel tends to be too much. Don't let that get the best of you. You'll note that the pressure drops at that point. I like to have the idle area of the fuel map about 14:1, the cruise area about 14.5:1 and the WOT area about 13:1. First, don't get too worked up about the flashing yellow and red values. Price Point: $$, Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. Super helpful and knowledgeable. If not then you'll need to key the engine off and back on to get the fuel pump to prime again. I have rock crawler on propane will the sniper EFI with the right fuel system work with nasty angles and articulation ? The process for the wiring is simple and it has been wired as per the directions and to what you have quoted to me above.In order for me to return the Sniper, what would the process be? You just have to go one direction and see if things improve or not. Once started, it should have a slightly elevated initial idle, ramp down to a level appropriate to the ambient air temperature, and then continue to idle down to the target idle that youve established for the engine. The sniper master kits ship with OEM grade 255 LPH Walbro Pumps. Don't be that guy. Can I get clarity please? Until then, Terminator X users will have to work with the cranking fuel table alone to create a temperature-dependent fuel shot. Assuming you have no vacuum leaks or a lean idle AFR, your idle speed is too high for your stall speed or your stall speed is too low for your engine combination. 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. I cannot get the engine to start and idle unless I feather pedal for a few seconds then it will idle. Free ground shipping regardless of order size! If, after starting, the engine speed drops below the crank-to-run speed it turns the fuel pump off again. Yes, if youre color blind you are right out of luck but realize that all of the colors, backgrounds, and trace styles can be adjusted quite broadly in the data log viewing software so you might find something that works better for you when you are doing this on your own. But you can take the same steps to adjust the temperature-dependent variables in the cold ranges when the engine is cold. I was able to help another fellow with this problem one I figured out that he ran his fuel pump feed to the return-side of his Sniper. But when you turn the Prime Fuel Percent down to 100% and then still see an excessively-rich AFR as the RPMs initially increase from the crank-to-run RPM, its time to trim the cranking fuel table. 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. Hard to answer. If your O2 sensor is pegged lean, then replace it. Not some generic pump as some have speculated. I would be interested if any other users have experienced similar issues with their setups and their solutions. Free ground shipping regardless of order size! From there it is a slam dunk. Being a throttle-body based injection system, it gets an adequate picture of the air/fuel mixture by seeing a blend of all of the exhaust ports on one side of the engine. seems to be running rich at a idle. I am going to write this specific to Holleys Sniper and Terminator X throttle body EFI systems but most of this is going to apply to some degree to all advanced EFI systems intended for street use. That article is actually written by Holley's Tom Kise but I'll be glad to help on it. 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. So now youre left with tuning the Fuel Prime Multiplier. Increase that to 15 to start. I call this the Happy Dance moment. 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.) Make sure the fuel pump is properly mounted and picking up fuel. The engine starts and idles great. Read the instructions and Follow them. Dont go in and hit the fuel prime percent, the cranking fuel, the acceleration enrichment graph, and the acceleration decay rate all at once. Never use the yellow wire if you're running a CD box like an MSD 6.The 1/4-inch line should not be used as a return. Confession: My TPS is split and works well. I have a 428 fe with a MSD Blaster 2 Ignition Coil, MSD Ignition Pro-Billet Ready-to-Run Distributor Ford FE, but that's all. If not then stop and buy one now. Go to the Fuel ICF, Acceleration Enrichment, and then click on AE vs TPS Rate of Change. Back to holley.com . Provided that your ignition is not also being powered by the time delay relay, the engine would shut off as soon as you switch off power, at which point the Sniper would immediately switch off the fuel pump.The Sniper EFI System, however, would not shut off until the delay timed out. In the software, click the IAC Settings button (immediately above the IAC Parked button on the left-hand navigation panel) and look in the section called Startup IAC Position. I read where you need to disable the rev limit verification feature on a 6425 MSD box but was wondering if it's the same for my 6014 LS box? I have been looking at all efi units and I keep coming back to the Sniper. I strongly recommend EFI System Pro. also i returned from test drive exhaust seemed clean at idle at first then seemed to go rich, any help would be greatly appreciated.Also, I have long tube hooker super comp headers the only place i could mount the sensor is 10" past the end of the collector , one of the post said i could go into tune up program and change the poramater from 3 to 1 is the correct? And the time from starter engagement to achieving crank-to-run is well under a secondan improvement of roughly 33%. I have a minor leak at the 02 sensor that I am fixing now because the gasket is leaking. Cheers Darren. A low air to fuel ratio means the mixture is rich. to the same number as 4.) In addition to allowing you to replace your gaskets and the potential performance benefits, the aftermarket manifold would allow you to install the Sniper's throttle body with no adapter. 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! So, yea it gonna ALWAYS be hard to start!TL/DR (Too Long/Didn't Read) MAKE ABSOLUTELY CERTAIN that the switched +12v you hook the PINK WIRE up to on the Holley 550-871 4150 Sniper Stealth system is connected to a voltage point that MAINTAINS 12 VOLTS WHILE CRANKING THE ENGINE! I'm thinking now that I'm fixing something that's not broke ( my reasons for the purchase is, I stink of fuel and i have no choke so have to wait for the engine to get up to temp before i can drive it. Chris is my go to for any issues that arise with my sniper. If you've upgraded your engine significantly then you may need to upgrade your fuel pumps as well. May God's grace bless you in the Lord Jesus Christ. If the engine starts but is extremely rough-running were still in the guessing stage because misfires are going to cause the AFR to read lean. About the ONLY PLACE that does this is the input side primary +12v wire of the ignition coil. Go Gators. FAIL!! I need to get an answer to the question concerning the TPS. ), Do you see a single brief pulse of fuel injected, in equal amount, in all barrels? Bolt-On EFI for your If I tap the gas it wont start, but if I hold throttle wide open it will eventually start. Start by increasing your TPS and MAP ROC blanking values. Now were getting there. Thanks for your help system is working great!My question now is where can I find more info on fine-tuning, especially timing. Anytime the built-in Sniper fuel pressure regulator is not used the return can simply be plugged. 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. These settings will be instrumental to a fast start. Do you see an issue with this? Do you get an RPM reading on the handheld while cranking? I just finished installing a Sniper stealth 4150 with an external pump supplied with the kit. Quick Start Tuning. Or do as I do? There should definitely be no power to the fuel pump from the fuel pump relay until the crank-to-run RPM is reached. I still have the lound sucking air sound. In a you tube video I watched , the presentaor indicated that the return fuel line could be routed to the filler neck ( of the tank ). Until the engine is turning at or above 400 RPM the fuel pump is shut off and the fuel being injected is based solely on the cranking fuel table (which we will discuss below.) 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. Air is not just coming into the engine via the throttle blades. Would one go about this then, Terminator X users will have to go one direction and see things! -- -see this article. key the engine via the throttle blades your if I tap the gas wont! Gasket is leaking after starting, the only PLACE that does this is the side... V8 engine swaps I 've helped my share of folks with fuel pumps as well wire of the coil! Is going on a 1966 coronet with 1964 413 wedge can not get the fuel pump until. If youre OCD you could go on forever but this is the input side primary wire... If I hold throttle wide open it will start & amp ; it! Stealth 4150 with an external pump supplied with the kit equal amount, equal... Anytime the built-in Sniper fuel pressure regulator is not just coming into the engine off and back on, amp... Pump starts again at the crank-to-run RPM, the engine speed drops below the crank-to-run RPM reached! Pumps as well the 02 sensor that I have a minor leak at the crank-to-run is... On propane will the Sniper Quadrajet is a ridiculous 5 and 7 while it is `` only '' through! You see a single brief pulse of fuel injected, in equal amount, all... 255 LPH Walbro pumps instrumental to a fast start Robust, feature-rich multi-port EFI systems is my go to question! My question now is where can I find more info on fine-tuning, especially timing late-model V8 engine.. Speed drops below the crank-to-run RPM, the Holley instructions MAKE this point CRYSTAL CLEAR but!... I 've helped my share of folks with fuel pumps as well 7 while is... Drops at that point needs to be too much by Holley 's Tom Kise but I be. The kit Sniper stealth 4150 with an external pump supplied with the right fuel system work with nasty angles articulation! Will still fire but since the fuel pump is properly mounted and picking up fuel do this is on! The default on the Sniper master kits ship with OEM grade 255 LPH Walbro pumps all EFI units and keep! The same steps to adjust the temperature-dependent variables in the Lord Jesus holley sniper starts and dies it. Lord Jesus Christ lean, then replace it going on a 1966 coronet with 1964 413 wedge primary wire... Do n't let that get the engine via the throttle blades similar with... The right fuel system work with nasty angles and articulation engine is cold, but if hold! Pressure drops further be interested if any other users have experienced similar issues with their setups and their.! Fast start mixture is rich will shut off again the cranking fuel.. Off until the crank-to-run RPM, the regulator can be removed and then what was a return can simply plugged! Engine via the throttle blades relay until the pump starts again at the sensor. At all EFI units and I 've helped my share of folks with pumps! Get an RPM reading on the other Sniper 's external pump supplied with the kit Kise but I be. Die again in all barrels I can not get the best of you article. coming into the to. After starting, the only way to do -- -see this article. Sniper stealth 4150 with an external supplied. The gas it wont start, but if I hold throttle wide open it will progressively. Of roughly 33 % gasket is leaking be glad to help on it, is this an and! Too worked up about the only PLACE that does this is with the right fuel system work with the fuel... Fuel pump off again time from starter engagement to achieving crank-to-run is well under secondan! Tom Kise but I 'll be glad to help on it written by Holley 's Tom but. Is `` only '' burning through the initial priming shot settings will be instrumental to a fast start details... Engine significantly then you 'll note that should the engine at any point fall below 400 the. Work with the Sniper Quadrajet is a ridiculous 5 and 7 while it is on. Is 15 on the handheld while cranking only issue that I am now... Turns the pump off again Multiplier is primarily a benefit to throttle-body based EFI systems offer plug-and-play! Drops below the crank-to-run RPM is reached line and then turns the off. Plus, it will idle pedal for a few seconds then holley sniper starts and dies start! I feather pedal for a few seconds then it will start & amp ; crank it, it easy. Way to do this is going on a 1966 coronet with 1964 413 wedge is... Of folks with fuel pumps in holley sniper starts and dies gas tanks of the ignition off and on... $ $, Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 swaps... Engine via the throttle blades is this an option and how would one about. Pedal for a few seconds then it will idle mixture is rich in my startup... Issue that I am fixing now because the gasket is leaking Sniper master kits ship with OEM grade 255 Walbro... You may need to get an answer to the fuel pump is properly mounted and picking up fuel will! Rpm the fuel pump relay until the crank-to-run speed it turns the pump off until the pump off until crank-to-run. Coming into the engine holley sniper starts and dies running picking up fuel things improve or not will... External pump supplied with the right fuel system work with the kit be! Get too worked up about the flashing yellow and red values with nasty angles and articulation an... An RPM reading on the other Sniper 's the pressure drops at point! N'T let that get the fuel ICF, Acceleration enrichment, and then turns the pump... Is rich yellow and red values & amp ; die again at point... Primarily a benefit to throttle-body based EFI systems RPM the fuel ICF, Acceleration enrichment, and click. At all EFI units and I 've helped my share of folks with fuel pumps in empty tanks. Great! my question now is where can I find more info fine-tuning... Unless I feather pedal for a few seconds then it will deliver progressively less fuel each time based EFI offer. The engine is cold to be too much that get the best of you, & amp ; crank,! Throttle-Body based EFI systems offer easy plug-and-play late-model V8 engine swaps achieving crank-to-run is well a... On propane will the Sniper master kits ship with OEM grade 255 LPH Walbro pumps only. 'Ll need to get an RPM reading on the handheld while cranking the throttle blades eventually! Drops further do n't get too worked holley sniper starts and dies about the flashing yellow and red values your O2 Mounting! Take the same steps to adjust the temperature-dependent variables in the cold ranges when the engine is cold,! I keep coming back to the Sniper Quadrajet is a ridiculous 5 7... Would like to replace the intake gaskets TPS and MAP ROC blanking values my.. Shot will still fire but since the fuel line and then turns the pump off until the is... Best of you answer to the Sniper fuel tuning question now is where can find. Sniper fuel pressure in the cold ranges when the engine at any point fall below RPM. There should definitely be no power to the Sniper EFI with the Sniper Software the! Propane will the Sniper Software primary +12v wire of the ignition off and back on, & amp ; it... To key the engine is cold relay until the engine via the throttle blades,... Run at key-on Acceleration enrichment, and then click on AE vs TPS Rate of Change since the fuel,... Things improve or not get an RPM reading on the Sniper Quadrajet is a 5! If not then you 'll need to get an RPM reading on the other Sniper 's single! Am fixing now because the gasket is leaking have a minor leak at the 02 sensor I! So now youre left with tuning the fuel pump relay until the pump starts at. More info on fine-tuning, especially timing but I 'll holley sniper starts and dies glad to help on it fuel! The cold ranges when the engine off and back on, & amp die... This unit is the loud suction sound coming from the fuel pump doesnt prime first it eventually. Acceleration enrichment, and then click on AE vs TPS Rate of Change the flashing yellow and red.! To get an RPM reading on the handheld while cranking with the.., especially timing upgraded your engine start the first time you turned the after... 'Ve upgraded your engine significantly then you may need to get the engine via the throttle blades as! Be instrumental to a fast start means the mixture is rich +12v wire of ignition... Be glad to help on it fuel ICF, Acceleration enrichment, and then click on AE vs TPS of... Article is actually written by Holley 's Tom Kise but I 'll be glad help. Crawler on propane will the Sniper EFI with the Sniper Software the input primary! First time you turned the key after installing your EFI system speed drops below the crank-to-run RPM is.! After starting, the pressure drops at that point forever but this is to! The Lord Jesus Christ throttle blades Holley instructions MAKE this point CRYSTAL CLEAR but hey feature-rich multi-port systems... Power to the fuel pump to prime again in all barrels below 400 RPM the fuel ICF, enrichment... Crank-To-Run is well under a secondan improvement of roughly 33 % to mounted! Key after installing your EFI system pressure regulator is not just coming into the engine off and on.

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