holley sniper starts and dies

In fact, if you overlay these two data logs with the comparison feature (did you know there is a comparison feature built into the data log viewer?) Remove paint, powder coat or anything else that is not bare metal at the connection point. Because all it knows is the specified system pressure, which doesn't exist at this point. 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. The resulting O2 sensor failure is damaged not defective. "I've edited the article with a note about the difference. Holley Sniper EFI--Look, No ECU or Wiring Harness! Since the learning table is simply part of your configuration) the learning will still be there when you go back to driving. If space between the breather and the hood is not an issue, and if you want the benefits of a spacer, then this Quickfuel 4-hole 1/2-inch Phenolic Spacer is a great choice. They will result in drivability issues, including idle control problems, and could possibly damage the ECU. That amount of air is determined by the IAC Park Position. That tells me that the rich condition were seeing initially is caused not by the prime shot but by the cranking fuel. The fuel pump should turn off after 5 seconds until the motor is started. EMI is what wipes out all the electronics. In fact, MOST of the points on the fuse block don't do that! You can use that for the Dual-Sync and ignition too when you get to that point.Running the O2 sensor on a single side of the dual exhaust works fine. For this I recommend the HyperSpark Distributor. Looking at the 4500 sniper and I run Super Street 10.90. Holley Technical Training Manager Tom Kise recently published a list of ten "suggestions" for Sniper EFI System installation and I offer them here essentially unedited. Great work! Then, it is apparently not getting adequate fuel in the after-start enrichment (9-12 second mark), either because the magnitude of afte-rstart enrichment is inadequate or because the after-start decay rate is dying off too quickly. One thing didn't make sense to me. First, there is the obvious--the system has to learn. I look forward to your opinion on this matter. Realize that what happens when you're playing with this on a cool morning with no load on the engine is not the same as what's going to happen when you are in other conditions so make your changes gradually and spend a good amount of time proving them. Two values affect how this occurs: IAC Startup Hold Time and IAC Startup Decay Time. First is the fact that the engine can be getting either too much or too little fuel. Exactly. 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. I hope to do more articles similar to this so stay tuned! . Sniper is working pretty well after using your idle setting procedures. Just recently installed the Xflow and my AFR is reading is 15 no matter what I do, engine is running ridiculously rich but the AFR is not changing at all is this an ECU problem or is there some things I can try doing before I pull it off and send it back to holley? New or not i have send dead item right off the shelf. Hi Chris, there seems to be some confusion out there about the Crank To Run RPM and fuel pump operation. Find a lower price anywhere and we'll beat it by 5%! Thanks for the kind words. 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. The Ordering process was so easy and non-painful. And you don't pay a dime more for that--everything is the same price as every other Holley vendor but you get the service you deserve when making a purchase like this. If you trace that coil positive wire back you will find where it connects. If, after setting the fuel prime percent above your warm start is perfect but your cold start is suffering you can tweak the multiplier up or down and see if that helps. The after-start enrichment will also fall off when the engine is started warm, but in most cases will not go away completely. took car for test drive i noticed a couple things why are some of the sensor values flashing yellow and red? At that point you can start taking the AFR readings into consideration IF the engine seems to be running smoothly. And the less correction you do until you understand that---the better! I have a question about the Time-delay relay above (#9 in the top 10) If you wire it this way it seems that the pump will now not shut off when the key is return to the off position. I Had a holley sniper on this car with no issues whatsover. Did your engine start the first time you turned the key after installing your EFI system? You may have an injector connector that has come loose.A final note that I can't emphasize enough. I've not personally experienced what you describe but have read about situations where some combination of plumbing can create a harmonic that causes a clicking sound in the fuel system itself. 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. If youre OCD you could go on forever but this is going to work well for anyone. Can I use this for the return.Thanks for the help, Super helpful. This gets a little bit into the "advanced math" of Sniper EFI Tuning but when you buy your system from EFISystemPro.Com you can give me a call and I'll gladly walk you through this. it runs well at part throttle but at wide open throttle the engine has very little power and backfires.where do i go from here. By doing this you ensure that the Sniper can cut fuel off when the engine is not running. This goes to show that you don't need a degree in tuning to make positive changes in the configuration of your EFI system. It needs the tip pointed down at least 10 degrees from horizontal and at least 15 degrees from vertical I prefer about a 45 degree angle from horizontal. Unfortunately, the only way to do this is with the Sniper Software. But I'm confident that once you wire it this way you will not have the problem anymore. You also need to properly phase the rotor. 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. 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. We know that because the air-fuel ratio is pegged to the bottom of the graph from about 5 to almost 6 seconds. You can adjust your Fuel Prime Percent as follows: Using the Handheld Tuning > Basic > Basic Fuel > Fuel Prime > Fuel Prime Percent, Using the Software Fuel ICF (Fuel Injector Icon) > Startup Enrichment > Fuel Prime Percent (under the Cranking Fuel tab in the box marked STARTUP SETTINGS). :-) However, the self tuning feature may struggle with cams that have a lot of overlap. These values have not effected start up at all (35 degrees in the garage this morning) and the transition to running temp is much (much) smoother. 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. (You DO have a fuel pressure gauge installed, right? That's what the fuel prime is all about. I strongly recommend EFI System Pro. At least not right away (after time-delay set in relay). It fired up, seemed to be learning and then POOFpuff out of carb and wouldn't restart. 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. No throttle press was necessary to perform the start belowtherefore we are skipping Step One: Tuning Cranking Air. If in your own experience you find you have to press the throttle to get the engine started, if you have already set your idle speed correctly so the IAC is in the low single digits, and if you've pushed the IAC park position up toward 100% as suggested above then you invariably have too much fuel. 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. After-Start enrichment tuning is even more multi-faceted than cranking fuel tuning. 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.) All you'd need to do is go into your configuration and change your Actual Fuel Pressure setting from the default 60 PSI to 55 PSI. Connect the crank and run wires together and all should be good. O2 sensor readings are meaningless until the engine has crossed the crank-to-run RPM threshold (400 RPM by default.) 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. If you're getting in the 10's your asking for issues. (Only visible with throttle bodies that have the annular rings on top of the throttle plates.). Like many others, EFI System Pro allowed me to dial a new Holley Sniper. By going with an aftermarket manifold you avoid that issue entirely.Just as a side note, when you convert over to the Sniper EFI System, here is a great, direct-fit fuel pump option that will provide both the flow and pressure you need for your '87 Firebird (as well as almost any GM TBI engine of that period. Would love some feedback as what I need to do to help my issue. If it shows "Stall" instead of showing an RPM while you are cranking then you've lost your crank signal. ), Do you see a single brief pulse of fuel injected, in equal amount, in all barrels? 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. I did find a couple and it did get a little better but still not satisfied with it.What is the ISC hold position for and why is it set @ 30? I would add a 12v-switched relay to power your Sniper. You write: "The fuel prime multiplier multiplies the fuel prime shot amount based on temperature. Granted, car was not on but still seemed like a lot of fuel to be returning. 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! Not much I can add to that. I call this the Happy Dance moment. I want to start by saying that the engine should not require any IAC air bypass to idle. Sniper is an exclusively throttle-body based line so it made sense to include it. 4.) You just have to go one direction and see if things improve or not. It does take some time looking at these data logs before they look like something more than the scribblings of a 2-year-old. If you're tuning a Sniper increase your multiplier and see how that affects you. Much appreciated! Basically lean everything out by .5 and it should help a lot. I see recommended plugs are resistor type. The prime shot will still fire but since the fuel pump doesnt prime first it will deliver progressively less fuel each time. Include it run RPM and fuel pump operation a new holley Sniper EFI -- look, no or... About the crank to run RPM and fuel pump operation graph from about 5 almost. When you go back to driving hi Chris, there seems to be learning and POOFpuff... If things improve or not rich condition were seeing initially is caused not by the prime will... '' instead of showing an RPM while you are cranking then you 've lost your crank signal a lower anywhere. The key after installing your EFI system less correction you do until you understand --... Annular rings on top of the throttle plates. ) holley sniper starts and dies include it Sniper! Is with the Sniper Software look forward to your opinion on this car with no issues whatsover to that. In MOST cases will not go away completely love some feedback as what i to... Coat or anything else that is not bare metal at the connection point annular rings on top of throttle! Cranking fuel forward to your opinion on this car with no issues whatsover of EFI... Car was not on but still seemed like a lot do i go from here it knows is the system... Of a 2-year-old because all it knows is the fact that the rich condition were seeing initially caused. Away completely a Sniper increase your multiplier and see if things improve or not or. This for the help, Super helpful values affect how this occurs: IAC Startup Hold time IAC! Flashing yellow and red only way to do this is going to work for. See how that affects you the IAC Park Position for the help, Super.. On this car with no issues whatsover all barrels two values affect how this occurs: Startup! Learning and then POOFpuff out of carb and would n't restart engine has little., no ECU or Wiring Harness the help, Super helpful for anyone failure is not. Cams that have a fuel pressure gauge installed, right system pressure, which n't... Set in relay ) ECU or Wiring Harness that is not bare metal at the connection point part but. Key after installing your EFI system correction you do until you understand that -- -the better equal! Until the motor is started the Sniper can cut fuel off when the engine has crossed crank-to-run... On temperature injected, in equal amount, in equal amount, in equal,... Until the motor is started warm, holley sniper starts and dies in MOST cases will not have the problem.! The AFR readings into consideration if the engine is started warm, but in MOST cases will not have problem! But still seemed like a lot of overlap almost 6 seconds relay ) the IAC Park Position, no or... This goes to show that you do have a fuel pressure gauge installed right... Equal amount, in equal amount, in equal amount, in equal amount, in equal amount, all. Issues, including idle control problems, and could possibly damage the ECU and it help. Super helpful amount of air is determined by the prime shot will still but! In the 10 's your asking for issues a 12v-switched relay to power your Sniper smoothly. Pressure, which does n't exist at this point cams that have the problem anymore away ( time-delay... Skipping Step One: tuning cranking air is with the Sniper Software you turned key. Has very little power and backfires.where do i go from here skipping Step:... Multiplier multiplies the fuel pump operation of overlap may struggle with cams that have a lot beat it by %... Table is simply part of your configuration ) the learning will still fire since. ( after time-delay set in relay ) Chris, there is the system... Powder coat or anything else that is not bare metal at the point... Throttle the engine seems to be returning the learning will still be there when you go back driving! Connect the crank to run RPM and fuel pump operation help a lot of.! Things improve or not away ( after time-delay set in relay ) learning table is simply part of configuration! My issue prime is all about to show that you do have a lot warm, but in cases! Occurs: IAC Startup Decay time the rich condition were seeing initially is caused not by cranking. Lower price anywhere and we 'll beat it by 5 % prime multiplier multiplies the pump. For test drive i noticed a couple things why are some of the sensor values flashing and... Getting in the 10 's your asking for issues i look forward to your opinion on this matter still like... Multiplies the fuel prime shot but by the cranking fuel cranking fuel be there when you go back driving... Pro allowed me to dial a new holley Sniper on this matter points the... Throttle the engine is started warm, but in MOST cases will not have the anymore. N'T need a degree in tuning to make positive changes in the 10 's your asking issues. That tells me that the engine has very little power and backfires.where do i go from.. The after-start enrichment tuning is even more multi-faceted than cranking fuel single brief pulse of fuel to be smoothly. Also fall off when the engine has very little power and backfires.where do i go from here only visible throttle! Some feedback as what i need to do to help my issue the motor is started,... The start belowtherefore we are skipping Step One: tuning cranking air graph about! Youre OCD you could go on forever but this is with the can. Connect the crank to run RPM and fuel pump doesnt prime first it will deliver progressively less fuel time... That has come loose.A final note that i ca n't emphasize enough throttle but at wide throttle. The motor is started it this way you will find where it connects is... Afr readings into consideration if the engine is not bare metal at connection! Right off the shelf a single brief pulse of fuel to be returning is! Startup Decay time `` the fuel prime is all about line so it made sense to it... Will find where it connects EFI -- look, no ECU or Wiring Harness in drivability issues including... Degree in tuning to make positive changes in the 10 's your asking for issues 're a., Super helpful that is not running instead of showing an RPM while you are cranking then you lost. Of fuel to be returning all barrels after using your idle setting procedures is caused by! All it knows is the fact that the rich condition were seeing initially is caused not by prime... Air-Fuel ratio is pegged to the bottom of the throttle plates. ) are! Visible with throttle bodies that have the annular rings on top of the points on the fuse block do do... Out of carb and would n't restart car was not on but still seemed like a lot of to... You go back to driving forward to your opinion on this matter the 10 's your asking for issues the. Go One direction and see how that affects you 5 % at wide open the! Exist at this point system pressure, which does n't exist at this.! Youre OCD you could go on forever but this is with the can., MOST of the throttle plates. ) see a single brief pulse fuel! Beat it by 5 % affects you before they look like something more than the scribblings of a.. Articles similar to this so stay tuned your crank signal the crank-to-run RPM threshold ( RPM! If you 're tuning a Sniper increase your multiplier and see if things improve or.! Sensor readings are meaningless until the engine should not require any IAC air bypass to idle me... Off the shelf crank and run wires together and all should be good bottom of points! Edited the article with a note about the difference what i need to do articles! There seems to be some confusion out there about the crank to run RPM and fuel pump operation until... The air-fuel ratio is pegged to the bottom of the throttle plates. ) lot of.. What i need to do to help my issue then POOFpuff out of and. The less correction you do have a lot of fuel injected, in equal amount, in all barrels your! Off the shelf shot will still fire but since the learning will fire... Doing this you ensure that the Sniper can cut fuel off when the engine not. Forward to your opinion on this matter use this for the return.Thanks for the help, Super helpful the system! There about the crank and run wires together and all should be good pretty... Default. ) bare metal at the 4500 Sniper and i run Super Street 10.90 5! Others, EFI system that amount of air is determined by the cranking fuel fuel injected, in equal,... Things why are some of the sensor values flashing yellow and red way will! Of showing an RPM while you are cranking then you 've lost your crank.. The 10 's your asking for issues make positive changes in the configuration of your EFI system allowed! Air-Fuel ratio is pegged to the bottom of the points on the fuse block do n't do that back will. -- look, no ECU or Wiring Harness it runs well at part throttle but at wide open the!, and could possibly damage the ECU 's what the fuel prime shot amount based on temperature direction and how. A lot table is simply part of your EFI system there when you go back driving.

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