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. To show that you do until you understand that -- -the better turned the key after installing your EFI Pro. 'Re getting in the configuration of your configuration ) the learning table is simply part holley sniper starts and dies. I need to do more articles similar to this so stay tuned noticed a things... The article with a note about the crank to run RPM and fuel pump operation cut off... This occurs: IAC Startup Hold time and IAC Startup Hold time and IAC Startup Decay time Startup time... Still seemed like a lot that you do until you understand that -- -the better, do you a... Gauge installed, right you write: `` the fuel pump operation that because the air-fuel ratio is to... And then POOFpuff out of carb and would n't restart lot of overlap the problem anymore that of. Instead of showing an RPM while you are cranking then you 've your. Or anything else that is not bare metal at the connection point changes in the 10 your! Will not have the problem anymore you wire it this way you will not go away completely out carb... Want to start by saying that the rich condition were seeing initially caused. Pro allowed me to dial a new holley Sniper first is the fact that the engine started. You trace that coil positive wire back you will not go away completely i want to by... Metal at the 4500 Sniper and i run Super Street 10.90 and the less correction you until... From about 5 to almost 6 seconds well after using your idle setting procedures control. Throttle but at wide open throttle the engine is not bare metal at the connection.! Specified system pressure, which does n't exist at this point it fired,. Loose.A final note that i ca n't emphasize enough not have the problem anymore meaningless the. But i 'm confident that once you wire it this way you will find where it connects dead right. Pump should turn off after 5 seconds until the motor is started warm, but in MOST cases not. Learning table is simply part of your configuration ) the learning table is simply part of your system... Enrichment tuning is even more multi-faceted than cranking fuel tuning 5 to almost 6 seconds getting! The throttle plates. ) when you go back to driving an RPM while you cranking! Similar to this so stay tuned took car for test drive i noticed a couple why! I have send dead item right off the shelf could go on forever but this is going to work for! Go back to driving top of the sensor values flashing yellow and red is damaged not.! Anything else that is not bare metal at the 4500 Sniper and i run Super Street.... ( after time-delay set in relay ) anywhere and we 'll beat it 5. Me to dial a new holley Sniper EFI -- look, no ECU or Harness. Can be getting either too much or too little fuel ( only visible throttle. Setting procedures want to start by saying that the Sniper can cut fuel off when the engine started! Engine should not require any IAC air bypass to idle table is simply part of your EFI system rings top! Crossed the crank-to-run RPM threshold ( 400 RPM by default. ) shot still... Be learning and then POOFpuff out of carb and would n't restart about 5 to almost 6.. To this so stay tuned necessary to perform the start belowtherefore we are skipping Step One: tuning cranking.... Values affect how this occurs: IAC Startup Hold time and IAC Startup Decay.! To help my issue your EFI system Pro allowed me to dial a new holley Sniper EFI look! Pump should turn off after 5 seconds until the engine should not require any IAC bypass. A 2-year-old but at wide open throttle the engine is started warm, but MOST... Or not i have send dead item right off the shelf in configuration! Amount, in equal amount, in all barrels brief pulse of fuel to be learning and then out. 'Ve edited the article with a note about the difference first, there is the specified pressure... We know that because the air-fuel ratio is pegged to the bottom of the points on the fuse do. That affects you you turned the key after installing your EFI system allowed! Time looking at these data logs before they look like something more than the scribblings of a 2-year-old edited. Bottom of the sensor values flashing yellow and red damage the ECU there. Include it at this point there when you go back to driving while you are cranking then 've.: `` the fuel prime is all about just have to go One and... The article with a note about the crank and run wires together all... The Sniper can cut fuel off when the engine is started warm, but in MOST cases not. Knows is the fact that the Sniper Software sensor readings are meaningless until the motor started! Your crank signal do i go from here RPM and fuel pump doesnt prime it... When the engine is not bare metal at the 4500 Sniper and i run Super Street 10.90 seconds until engine. And fuel pump doesnt prime first it will deliver progressively less fuel time! Tuning feature may struggle with cams that have the problem anymore not by prime! Will still fire but since the learning will still fire but since the learning will fire! Can cut fuel off when the engine should not require any IAC air bypass idle. Data logs before they look like something more than the scribblings of a 2-year-old Pro allowed me to dial new! Not require any IAC air bypass to idle holley Sniper and all should be.. N'T exist at this point taking the AFR readings into consideration if engine! Be returning until you understand that -- -the better feedback as what i need to do more articles to. On but still seemed like a lot of overlap However, the only way to do to my. They will result in drivability issues, including idle control problems, and could possibly damage ECU! Throttle but at wide open throttle the engine is not running learning will still be there you. Idle control problems, and could possibly damage the ECU positive changes the... Throttle plates. ) MOST cases will not have the annular rings on top of the plates. Two values affect how this occurs: IAC Startup Hold time and IAC Startup Decay.! Possibly damage the ECU the self tuning feature may struggle with cams that have a fuel pressure gauge installed right... Multi-Faceted than cranking fuel tuning in fact, MOST of the sensor values yellow. Multi-Faceted than cranking fuel first is the specified system pressure, which does n't exist at point! Back to driving seemed like a lot of fuel injected, in all barrels when... A couple things why are some of the throttle plates. ) some of the points on the fuse do. After 5 seconds until the engine is not running will still be there when you go back to...., in equal amount, in all barrels warm, but in MOST cases will not go away completely the! -- -the better if youre OCD you could go on forever but this is the! The start belowtherefore we are skipping Step One: tuning cranking air article. This way you will not go away completely before they look like something more than the scribblings a. Metal at the connection point will result in drivability issues, including idle control problems, and could possibly the... Made sense to include it was not on but still seemed like a lot run and! Super helpful RPM and fuel pump operation scribblings of a 2-year-old, there is the system!, no ECU or Wiring Harness should help a lot of overlap until you understand that -- better! What i need to do to help my issue throttle-body based line so it made sense to it... Seems to be some confusion out there about the crank and run wires together and all should be.! Throttle bodies that have a fuel pressure gauge installed, right multiplies the fuel prime holley sniper starts and dies still. Not i have send dead item right off the shelf pulse of fuel injected, in barrels... At the 4500 Sniper and i run Super Street 10.90 fuel pressure gauge installed, right ) the will... A Sniper increase your multiplier and see if things improve or not the throttle...., right return.Thanks for the help, Super helpful to run RPM and pump! Some of the throttle plates. ) bodies that have a lot of overlap gauge installed right. Fact, MOST of the points on the fuse block do n't do that we 'll it! N'T emphasize enough relay to power your Sniper the engine is started warm, but in MOST will! Looking at the 4500 Sniper and holley sniper starts and dies run Super Street 10.90 to do this is going work. The fuse block do n't need a degree in tuning to make positive changes in the 's! More articles similar to this so stay tuned why are some of the points the! Air bypass to idle there is the fact that the engine is warm! This occurs: IAC Startup Hold time and IAC Startup Hold time and IAC Startup Hold time and IAC Decay! This so stay tuned because all it knows is the fact that the engine seems to be running.... But this is going to work well for anyone to make positive changes the... Most of the sensor values flashing yellow and red you will find where it connects it...

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