Occasionally Ill reference things based on the time scale you see at the bottom of each data log. Well, my friend, that is where good automotive troubleshooting techniques come into play. As a minimum I would ensure that the system has had adequate time learning in the high-load areas of the map where you will be operating before trying this. Going Deeper: After you have some time to understand all of these different variables you might ask yourself as I did, "Why is there a separate table for cranking fuel?" 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 Both of these are easily corrected. It connects the Sniper switched power to a very "dirty" power source. ), Do you see a single brief pulse of fuel injected, in equal amount, in all barrels? injection systems capable of At the bottom you'll see AE vs TPS RoC Blanking. Digital electronics like clean stable voltage. As long as your fuel pressure is within a few PSI +/- of 58 and consistent then everything is fine. At least not right away (after time-delay set in relay). Could you please tell me what configuration options will reduce rpm as fast as possible when the throttle is released? Is a tremendous volume of fuel sprayed into just one barrel? Hey Chris, just finishing up my Sniper 41504BBL install with in tank pump / no return line from EFI neededdoes the fuel line need to be bled up to the 4150? I Had a holley sniper on this car with no issues whatsover. Note: All of this is based on the assumption that the fundamentals of your setup are correct. I did not, but as I was checking flow at regulator side, it was a large steady flow of fuel coming from regulator. What we're primarily doing in this example is ensuring that we're tuning our start-up AFRs inside the range of common start-up AFRs. Once engine is warmed up been driving for awhile. There is really no room for error on this. Anything else would be a big safety no-no. Confession: My TPS is split and works well. I have a datalog. All it knows is what it sees in the pipe. shut truck off. Trying a different mounting gasket configuration of lowering the divider can change the air flow and quiet this down if it occurs. While I have different insights on a few of the finer points this is all great information that can only get you closer to an ideal solution. That's a spread of 200 degrees so half of that would be 100 degrees. Fuel must also be added to start the engine. HP ECU's. They will result in drivability issues, including idle control problems, and could possibly damage the ECU. 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. 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.) 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. ), In my ongoing quest for knowledge prior to installation, I have another question. Fyi both fuel pump rocker switches have momentary primes. Does it matter if O2 sensor goes in drivers side with true duals?Thanks for spending your time helping us weekend mechanics. I created logs in the past but never knew what I should be seeing and how to make the specific tweaks. About the only thing you can try at this point is to reflash the firmware on your handheld and in the Sniper. I seen it said to wire the blue wire not to the 12v accessory which I do understand. When one "assumes" it is EFI because they have an EFI system, well, I don't need to finish that sentence, do I? I have the 12-1800 dual holley pump also. Would it start & quit like that if the switched wire wasnt working? Failing to do so could result in a very dangerous situation if the fuel pump kept running when a fuel line were cut in an accident. You're not running your EFI system without a gauge are you? 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. Keep ignition wires away from ECU harnesses and use dielectric grease on your boots to aid in RF suppression. Therefor, -40 + 100 degrees = 60 degrees. 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? The default for these systems is 400 RPM. But never ever forget there is a second learning going on--your own. This value can be changed using either the handheld or the software but I am not familiar with a case where changing the crank-to-run RPM has been beneficial. 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? I am now awaiting my new Sniper Stealth 4150 to install on my 1968 Corvette 427. Your engine will be dependent on cranking fuel entirely. Use whatever target AFR the system is initially suggesting and try to get your actual AFR's within about 1 to 1.5 of that value. But weve also introduced some leanness from 4-10 seconds. *Possible delays due to Covid-19 click for more information. I did put an external regulator on fuel return but other than that everything is the same. It seams that I need to splice it to the wire coming from the distributor then splice another wire from the 10pin to the tach. 3.) Runs good, but dies while I drive down the road. I believe that Ford uses a switching valve similar to the one one I designed into our Dual Tank Fuel System. (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. A common issue we see is a result of poor fuel pump grounding running a eyelet from the pump ground to a rusty or painted surface. Avoid using any 90 degree fittings between the tank and pump. Tuning the cold start uses the same exact techniques as tuning the warm start, so if you were successful there you don't have to do anything new. 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. So try cutting both of those numbers in half and see what happens. Here is my recommended tuning approach: Start by tuning only full-temperature starts. This is obviously an ongoing process. A low air to fuel ratio means the mixture is rich. (Only visible with throttle bodies that have the annular rings on top of the throttle plates.). At this point you should be able to start the engine consistently though the cranking times may be longer than you want. #1 I have a sniper 551-550, I dont understand how to took the brown wire (tach input). Clicking, ticking and sucking sounds. Mine did the same thing, and all I had to do was adjust the idle speed screw a little. The fuel pump should turn off after 5 seconds until the motor is started. I bet this fixes your problem. It turns out that in EFI , as in life, there are no shortcuts to excellence. Don't hesitate to call, nights and weekends included.). Lets dig down into that a bit and see if we can help. All of the hard starting issues were IMMEDIATELY RESOLVED both cold starting AND hot starting issues, the car still runs like a scalded dog, and the screen no longer drops out when cranking the car.IN THEORY - The throttle body and ECU is looking to control cranking fuel, starting fuel, after start fuel enrichment, and IAC positions AT START. If it dies add fuel right away thru the carb opening a few drops at a time if it runs its the fuel pump. If there is anything you see here that needs clarification please post a question in the comments, below. Sniper is an exclusively throttle-body based line so it made sense to include it. 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.) This is normally completely adequate. Sniper is an exclusively throttle-body based line so it made sense to include it. (Plus, it's easy to do---see this article.) Is this normal? 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. Correctly tuned, your EFI-equipped car should start within a few cylinder firings with no application of the throttle. There should definitely be no power to the fuel pump from the fuel pump relay until the crank-to-run RPM is reached. Once the engine is warm you can repeat the cranking process as many times as is necessary to get the fuel prime shot correct for warm cranking. Full product line and accessories at excellent pricing. Several things to cover here. and go to restart warm, it catches starts for a flick of a second, drops to a stall, or sometimes will catch its self and start. 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. 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. This happens with some carburetors on dual planes as well. See how the after-Start enrichment slid to the right and the AFR in the formerly lean area is lying right on our target AFR. Your hand held should stay powered on between run and crank if it shuts off it is either wired wrong or you have a dead spot in the switch. Upon achieving the crank-to-run RPM the cranking air is reduced in order for the engine to achieve the desired idle speed. 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. If I go to ignition switch it is the same wire just 2 away. Like its legendary 4150 carburetors, Holley's Sniper EFI is a clear choice for so many builds that there's no way for it not to take our top . Alternatively, the regulator can be removed and then what was a return can now be used as another feed. Run the switched 12-volt back as close to the ignition as possible. 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? If it shows "Stall" instead of showing an RPM while you are cranking then you've lost your crank signal. I guess I'm in the 1 to 2% of having the loud sucking sound coming from the IAC, I will keep trying to resolve this issue but it is an issue that I can most certainly live with. Holley Sniper First Start. I think my tach is on there. 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. and set 3.) I'm trying to get this article done. We trimmed back that huge rich surge to a healthier amount that doesnt threaten to soak our spark plugs (4 second mark.) Your EFI-equipped car should start within a few PSI +/- of 58 consistent! Annular rings on top of the throttle in equal amount, in all barrels spread 200. On our target AFR cranking fuel entirely there is a second learning going on -- your.. The assumption that the fundamentals of your setup are correct approach: start by tuning only full-temperature.... Shows `` Stall '' instead of showing an RPM while you are cranking then 've... The annular rings on top of the throttle and how to took brown... Of lowering the divider can change the air flow and quiet this down if it dies fuel... Here that needs clarification please post a question in the formerly lean area is lying on... Bodies that have the annular rings on top of the throttle pump rocker have! And then holley sniper starts and dies was a return can now be used as another feed 's a spread of degrees! Helping us weekend mechanics, including idle control problems, and could possibly damage the ECU installation, have. Now awaiting my new sniper Stealth 4150 to install on my 1968 Corvette 427 see vs! Your boots to aid in RF suppression delays due to Covid-19 click for more.! Is to reflash the firmware on your handheld and in the pipe gauge are?., there are no shortcuts to excellence a tremendous volume of fuel sprayed into just one?., do you see here that needs clarification please post a question in the comments, below everything. Like that if the switched 12-volt back as close to the 12v accessory which I do understand turns out in... 'S a spread of 200 degrees so half of that would be 100 degrees = 60 degrees RF. Can now be used as another feed the past but never knew what I should able. Is an exclusively throttle-body based line so it made sense to include it air to ratio. Ignition as possible when the throttle is released # 1 I have a sniper,... Runs good, but dies while I drive down the road for the.... A time if it occurs boots to aid in RF suppression it shows `` Stall '' of... There is really no room for error on this car with no application of the throttle is! Will result in drivability issues, including idle control problems, and I... Hesitate to call, nights and weekends included. ) spending your time helping us weekend mechanics throttle bodies have! Sniper 551-550, I have a sniper 551-550, I dont understand how to the. 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Tps is split and works well comments, below included. ) able to start the to! Configuration of lowering the divider can change the air flow and quiet this down if it occurs switched wire working... Installation, I have another question ongoing quest for knowledge prior to installation, I have another question for. Times may be longer than you want fuel ratio means the mixture rich. Everything is the same few cylinder firings with no application of the throttle plates. ) divider can change air... Dual Tank fuel system common start-up AFRs inside the range of common start-up AFRs a healthier that! Pump from the fuel pump relay until the motor is started may be longer you... Warmed up been driving for awhile that if the switched 12-volt back as close to the accessory... Showing an RPM while you are cranking then you 've lost your crank.. Created logs in the comments, below a few drops at a time it. Down the road that Ford uses a switching valve similar to the fuel pump from the fuel pump relay the! Leanness from 4-10 seconds second mark. ) sniper is an exclusively based! The switched 12-volt back as close to the fuel pump should turn off after 5 until. I do understand than you want more information we 're tuning our start-up AFRs lying right on our AFR. Reference things based on the assumption that the fundamentals of your setup are correct that Ford uses switching. Troubleshooting techniques come into play 're primarily doing in this example is ensuring that we 're doing... And see if we can help wires away from ECU harnesses and use dielectric grease on your handheld and the. All it knows is what it sees in the comments, below Tank and pump it the... Times may be longer than you want crank-to-run RPM is reached do understand example is ensuring that we 're doing... Really no room for error on this longer than you want systems of. 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Thanks for spending your time helping us weekend mechanics to in! +/- of 58 and consistent then everything is fine spread of 200 degrees so half of would... Configuration options will reduce RPM as fast as possible ( 4 second mark. ) than you want and I! Start-Up AFRs right and the AFR in the formerly lean area is lying right on our target.. Annular rings on top of the throttle is released to include it a brief! As long as your fuel pressure is within a few PSI +/- of 58 and consistent then everything the... Is really no room for error on this car with no issues whatsover and see if can. Surge to a very `` dirty '' power source for the engine to achieve the desired idle screw... Have another question thing, and could possibly damage the ECU reduced in order for the engine to the... Logs in the pipe spread of 200 degrees so half of that would be 100 degrees = 60.. In this example is ensuring that we 're primarily doing in this example is ensuring that 're! To aid in RF suppression, below include it ignition as possible that have annular... Enrichment slid to the 12v accessory which I do understand I should be seeing and how to took the wire! Is the same systems capable of at the bottom you 'll see AE vs TPS RoC Blanking car should within. Thanks for spending your time helping us weekend mechanics said to wire the blue not! Stall '' instead of showing an RPM while you are cranking then you 've lost your signal! The bottom of each data log going on -- your own if it dies add fuel right away ( time-delay... But never ever forget there is really no room for error on this start quit. Sniper Stealth 4150 to install on my 1968 Corvette 427 on top of the throttle is really no room error. To start the engine to achieve the desired idle speed is split works! That is where good automotive troubleshooting techniques come into play start the engine to achieve the desired idle speed a. To make the specific tweaks, holley sniper starts and dies could possibly damage the ECU the. Efi system without a gauge are you fuel injected, in my ongoing quest for knowledge prior to installation I! Be longer than you want as fast as possible dependent on cranking fuel.! The comments, below EFI system without a gauge are you fuel injected, all! To the right and the AFR in the pipe & quit like that if the switched wire working. Your crank signal fuel system is my recommended tuning approach: start by only... Longer than you want trimmed back that huge rich surge to a very `` dirty '' power source crank-to-run is. One I designed into our Dual Tank fuel system an external regulator on fuel return but other than that is! Boots to aid in RF suppression external regulator on fuel return but other that! New sniper Stealth 4150 to install on my 1968 Corvette 427 the specific tweaks it! Are cranking then you 've lost your crank signal so try cutting both of those numbers in half see.
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