holley sniper starts and diesholley sniper starts and dies

We have not heard of any problems with the Sniper and the Pertronix Ignitor 2. Like many others, EFI System Pro allowed me to dial a new Holley Sniper. I have a sniperstealth witch dui ignition and Holley in tank pump. Bolt-on carburetor style EFI for your classic car or truck. Because all it knows is the specified system pressure, which doesn't exist at this point. I'm lucky to get two warm up cycles a day and then it is a moving target - but I've made considerable progress. Once engine is warmed up been driving for awhile. My first rule: There has never been an engine that didnt start because EFI. Dont go in and hit the fuel prime percent, the cranking fuel, the acceleration enrichment graph, and the acceleration decay rate all at once. 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 ). Holley did not include it on the Terminator X, which started life as a multi-point EFI ECU. Idle and cruise can be tuned leaner with "seat of the pants" feel. Great work! 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). I am having a 2 572 BBC being built for my boat. Be sure to properly gap your plugs and if you plan to run Magnetic pickup distributors for timing control. Much appreciated! If it dies or drops more than 50-75 RPM the throttle is closed too far. The xflow instructions state it needs 60 psi. But as the temperature decreases the IAC Park Position (and therefor the air allowed to pass) increases, all the way to wide open (100%.). It starts fairly well. I've had this throttle body for a few months, haven't put 10 miles on it since I installed it. Enjoy! It will work on three, two, or even one cylinder of exhaust, but with each reduction past four you increase the likelihood that you are not seeing a balanced mixture and that your closed loop correction is going to be inaccurate.The purpose of putting distance between the merge point and the O2 sensor itself is to ensure that the exhaust is mixed adequately. Do as I Holley says? As long as you're that far into the pipe (to prevent reversion from feeding air back into the O2 sensor) then I wouldn't worry just now about changing the settings.In general, I recommend not touching a thing until you've spent a significant amount of time driving under varying driving load and RPM conditions. As a result, this same engine may not start well cold. But I have MSD 6 AL. It is also coming through the idle air port. Once I got it close using your instruction, I was able to make micro adjustments while it was running to get the IAC to 1-2. At -40 degrees it multiplies it by the full indicated amount (five times, by default.) If you're installing a Sniper EFI system and almost ready to crank it over for the first time, this is the video for you! Icle > IAC Startup > IAC Park Position, Using the software Idle ICF (tachometer icon) > IAC Parked Selection. The sole purpose of this is to prevent stalling, so change one thing at a time and if you find your engine stalling then back up a bit.The four key settings:1.) Thats because EFI isnt one of the three things that are required for the engine to run. to zero, but I think you'll find that you will stall. Latest Articles. The IAC Park Position is a temperature-dependent value that can be adjusted in the following ways: Using the handheld Tuning > Advanced > Adv. multi-port EFI systems Upon achieving 400 RPM, the ECU turns on the fuel pump and injects the fuel specified by the base fuel map and learn table, supplemented with after-start enrichment and coolant modifier fuel (as shown below.). All it knows is what it sees in the pipe. For TWO YEARS Since installing my Sniper Stealth 4150 (Holley 550-871) on my small block Camaro, I've been chasing hard start cold or hot issues. Turning the idle speed screw in the other direction (counterclockwise) will allow the throttle blades to close. By doing this you ensure that the Sniper can cut fuel off when the engine is not running. It just can't work properly.But there are options for making it work provided you source your RPM from something other than the ignition. 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. I prefer solder and heat-shrink but technically speaking a well-executed crimp-connection is actually superior. features . We do see a massive rich dip in the AFR as soon as engine starts. 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. What is FAR more of an issue is that you have no exhaust leaks either before or up to 18 inches or so after the O2 sensor. Full product line and accessories at excellent pricing. (If the Sniper does not get a RPM signal, it will not inject fuel.). Does pressing the throttle slightly allow the engine to start. I have the 12-1800 dual holley pump also. Then, click on AE vs MAP Rate of Change and change that to 15 as well. Holley Sniper RobbMc Surge tank Edelbrock high volume 10PSI Fuel pump Sniper CD box Sniper Coil Sniper Hall effect distributor In cabin Electric Fuel Pressure gauge I was having intermittent lean spikes with my Sniper and I thought I traced it to my mechanical fuel pump not producing enough volume/pressure to the the Surge tank. Capability Range: Advanced There must be an option that has been found to work. And that from a not-so-shabby original 1.13-second start time. 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. The sniper master kits ship with OEM grade 255 LPH Walbro Pumps. 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? You will still get a prime shot each time you key the system on but once you start cranking it will not deliver cranking fuel and should eventually clear itself of the flooded situation and fire. The IAC is essentially a computer controlled vacuum leak that allows additional air past the throttle plates to assist in idle stability and additional cold idle speed. After pulling the trigger on the Holley sniper I'm now getting worried about fitting it, I've read that the EFI doesn't like a big cam because of the overlap and its possible i will lose the lumpy idle. Oil control: If you're burning oil you will kill your O2 sensor, closed loop chasing unstable fuel supply issues( see fuel pumps comment). If that is your situation I would expect the pressure to oscillate as you describe. In the example below, the IAC Park Position is at 50 percent at normal operating temperatures. Have you ever watched a post nuclear apocalypse movie? 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. Hard starting cool but starts easy when hot. However, each engine is different. Is the Sniper EFI system rev-limiter capable. Certainly that seems like a good idea, though I've not seen Holley recommend it in any of their documentation and have never experienced a case where I felt the initial start-up was delayed because it was not bled. Yes, all warranty replacement and repair claims must be handled through the retailer from which you purchased the unit. A key at the top of each log shows the signals associated with each color. If your pressure drops the system will react by adding fuel in closed loop and lean. And 10 micron filter between the pump and throttle body. The better option is to use a bulkhead fitting, hose-barb adapter, and convoluted PTFE hose that reaches the tank where possible. With the engine at full operating temperature you should be able to stick your finger in the IAC inlet port on top of the throttle body and the engine should simply idle down about 50 RPM below your programmed idle speed. 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? 4.) If I do that right (about 500 ms should do it) then the after-Start enrichment will not come in while were still in that rich region coming right off initial fire-up. This is most often a result of air flowing through the IAC port related to the IAC hold Position and is normal. 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. Most import. Anouther cause may be the proximity of a dual plane intakes plenum divider to vacuum passages under the throttle body resulting in an odd sucking or whistling sound. You'll note that the pressure drops at that point. If your engine starts well, sounds good during the hold, but then fails a bit after the decay you can extend these out a bit. Also, if you have the IAC inlet plugged off and the throttle angle is set to your desired idle speed and it dies when you put it in gear with an automatic. Full product line and accessories at excellent pricing. I am now awaiting my new Sniper Stealth 4150 to install on my 1968 Corvette 427. Sometimes, the thing would start and run, and other times it was most difficult to start. Instead, what most folks find is that the sucking/slurping sound that comes in a very few of the Sniper installations can be solved completely by installing a spacer gasket between the Sniper throttle body and the intake manifold. Actually, as long as you are driving the fuel pump with the blue wire from the Sniper EFI System it will shut that down as soon as the RPM drops below the crank-to-run RPM (400 RPM by default.) Not some generic pump as some have speculated. While cranking are you getting a reasonable RPM signal while cranking (usually about 150 RPM)? Could be, I initially had mine not wired to a 12V source while cranking, and it did the same thing yours is doing. 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 would be interested if any other users have experienced similar issues with their setups and their solutions. Once you determine how much you adjust the cranking fuel in the warm range you can either leave the rest of the range alone to see how it starts cold or else just adjust the entire cranking fuel table by the same amount that youre using to create an efficient warm start. Proper plug readings would need to be done to confirm if you can go any leaner WOT tuning. I have a light flywheel and high compression - also a close ratio 6 speed racing manual trans and I need the rpms to drop asap for shifting. Quick to respond and very knowledgeable. Chris, I install a Holley Sniper Quadrajet on my 1976 GMC classic motor home with a 455 cu Oldsmobile. I feel I could then use the Startup Enrichment parameters (After Start Enrichment and Decay Rate) to fine tune from there. O2 sensor readings are meaningless until the engine has crossed the crank-to-run RPM threshold (400 RPM by default.) 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 have been looking at all efi units and I keep coming back to the Sniper. Until then, Terminator X users will have to work with the cranking fuel table alone to create a temperature-dependent fuel shot. Is a tremendous volume of fuel sprayed in all barrels? One thing didn't make sense to me. Note that the closed loop is not normally operational during start-up fueling so there is no benefit to the start-up in changing the target. This is a bit tricky. I can't find a good spot in the fuse block, I don't recommend this. Goat Rope Garage 76.3K subscribers Join Subscribe 176 Share 27K views 2 years ago Support Those Who Support The Garage HPTuners: http://www.hptuners.com Show. 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. Why? If so then it is (regardless of what the O2 sensor says.). Remove paint, powder coat or anything else that is not bare metal at the connection point. If you install your Sniper EFI System and then find that you are experiencing that noise, then it is a fairly simple matter to order the gasket or spacer and slip it into place. superchargeddrt Well-Known Member Joined Aug 24, 2009 Messages 2,420 Reaction score 1,102 I've been running the super sniper 1250 on my 6.2 ls for several months now and am still fighting cranking issues. A tube type 90 is equal to adding 3 feet of fuel line between the tank and pump. All times are GMT-6. 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. ), Do you see a single brief pulse of fuel injected, in equal amount, in all barrels? The only issue that I have with this unit is the loud suction sound coming from the IAC port. EFI Systems based on Holley's world-class Dominator and HP ECU's. Do you see an issue with this? More or less how do I build a timing curve?As it goes straight to these numbers with no compensation for RPM or other factors. There is certainly some conflicting information on O2 sensor installation. (Plus, it's easy to do---see this article.) What is important is that you understand what happens at this point. If, after starting, the engine speed drops below the crank-to-run speed it turns the fuel pump off again. In all fairness, the Holley instructions MAKE THIS POINT CRYSTAL CLEAR but hey! And you are in luck--I wrote an article on improving the timing control on the Sniper EFI System. Now were getting there. 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. I believe that this compensates for the fact that during cranking fuel injection the fuel pump is not running. For this I recommend the HyperSpark Distributor. Im installing a sniper on a 49 Ford f1 with a 302 and still have the original behind the seat tank. How to Tune Acceleration Enrichment in Holley EFI // Terminator X, HP, Dominator & Sniperonce again, i made a video too long. Did your engine start the first time you turned the key after installing your EFI system? But you can extend the leads using wires of an equal or heavier gauge. If it dies add fuel right away thru the carb opening a few drops at a time if it runs its the fuel pump. 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.) 2.) Hi, I have a 1987 Firebird with 305 engine and Quadrajet carb. Just realize that you risk aerating the fuel a bit depending on how it enters the tank. I have rock crawler on propane will the sniper EFI with the right fuel system work with nasty angles and articulation ? Seems like thats what its doing. Thanks Chris for the quick reply, I have already installed a spacer, part # Aluminum Carburetor Spacers SUM-G141. Anytime the built-in Sniper fuel pressure regulator is not used the return can simply be plugged. I always recommend fixing one thing at a time. Read the instructions and Follow them. So only crank and ignition on hot I have is where ballast resistor was but it still feeds coil?Can I connect 12 volt switched here and add one way ballast resistor going to coil and switched efi wire at this point to elininate back feed? So you be the judge. But weve also introduced some leanness from 4-10 seconds. Get a gauge. Connecting a grounding strap from battery to frame with a frame to engine may have been OK for your carburetor but its not sufficient for digital electronics. 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. Your advice would be appreciated. THAT'S A PROBLEM!The Holley install manual CLEARLY STATES to make sure whatever switched 12 volt source you connect the PINK WIRE to, that it MAINTAINS VOLTAGE WHILE CRANKING THE CAR!! I make a lot better electrician than mechanic but have built cars all my life. The pump needs to be GRAVITY FED, meaning the pump inlet needs to be at or below the bottom of the tank and as close to the tank as possible. I just moved it to the ignition terminal on the fuse block and voila, it ran. Start by first cutting the fuel prime to 100% and taking about 20% out of the cranking fuel in the temperature range of the engine. Go Gators. I have checked my wiring and also had an auto electrician check it all out also. Each time you key on the system longer than the four seconds or so that it takes to deliver the prime shot, a prime shot will be delivered. One thing I miss is the instant drop in rpms that my 650DP had. If it is more than about 5 PSI one way or the other, or if it changes under different operating conditions, then you should look into that. The "Service AFTER the Sale" is why I came to EFI SYSTEM PRO, getting a system working with great support makes for a better installation and happy customers! The Ordering process was so easy and non-painful. Thats what we want, right? 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. Check your fuel pressure during installation at both the feed and return lines. I figured it would be minimal. But what if it doesnt? So making the right buying decision means you get the support you need from a Holley Tier-III certified professional at no additional cost..If you've made that purchase decision already but would like to get some help, you're not out of luck. Do you have fuel pressure? But I strongly suspect that is not the case. Hi I am running a Hyperfuel pump part #40019 with a 58 psi regulator built in to the pump am I safe to run this with my holley xflow or should I be removing the fuel pump regulator and installing one on the return line? If you trace that coil positive wire back you will find where it connects. Bolt-On EFI for your If it dies again after this it must be a bad coil. If that works then try halving them again. The images are NOT intended to provide you with the values you should be using in your configuration. Bolt-on carburetor style EFI for your classic car or truck. And if you compare the default cranking fuel values to the default fuel map values you see that the cranking fuel is WAY more. That clicking sound you may be hearing is most likely the fuel injectors cycling, this sound is often more pronounced at Low RPM. There is no programming, per se, to switch from closed loop (where the ECU is controlling the fueling based on input from the O2 sensor) to open loop (where the O2 sensor is ignored.) A brief spray of fuel is injected before cranking. 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. Do you have issues with cold start that go away with warm start, or vice versa? There exists an engine speed above which the ECU assumes the engine is running as opposed to cranking. We know that because the air-fuel ratio is pegged to the bottom of the graph from about 5 to almost 6 seconds. 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! Similarly the fuel pump should be grounded directly to the battery using a wire of at least as heavy a gauge wire as the blue fuel pump power wire from the Sniper. At that point you can start to correlate what is proper behavior and what needs correction. A tube type 90 is equal to adding 3 feet of fuel line between the tank and pump. Does it matter if O2 sensor goes in drivers side with true duals?Thanks for spending your time helping us weekend mechanics. EMI is what wipes out all the electronics. It appears to be in throttle body? Now, at each RPM setting you'd add (or subtract) whatever from the Target AFR so that the new target is 14.0:1. 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 does take some time looking at these data logs before they look like something more than the scribblings of a 2-year-old. You may have an injector connector that has come loose.A final note that I can't emphasize enough. The problem isn't the 55 PSI. At that point you can start taking the AFR readings into consideration IF the engine seems to be running smoothly. Youve spent all this time wondering if this whole experiment in EFI was going to work and on the first start it cranks and runs beautifully. Chris, this is going to be an easy one. But you can take the same steps to adjust the temperature-dependent variables in the cold ranges when the engine is cold. Not much I can add to that. It turns out that in EFI , as in life, there are no shortcuts to excellence. 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. When you remove a spark plug is it bone dry or dripping wet? Most important!!! I am now awaiting my new Sniper Stealth 4150 to install on my 1968 Corvette 427. Don't be that guy. I'm glad this approach worked for you. Yes, the fuel pump comes on initially to prime the line but then it shuts off and fires the prime shot. If you do not understand a step seek assistance. 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. I have a minor leak at the 02 sensor that I am fixing now because the gasket is leaking. Third is the truth that every engine has its own preference on what it likes for startup fuel. If you're tuning a Sniper increase your multiplier and see how that affects you. First is the fact that the engine can be getting either too much or too little fuel. That is not the case. Hard to answer. 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. Try cranking immediately upon key-on--before it has a chance to prime. Then, after I reconnect everything I'll key the system on a time or two until I see a reasonable amount of fuel pressure on the fuel pressure gauge. Price Point: $, Advanced throttle body injection systems capable of transmission control and more. Avoid using any 90 degree fittings between the tank and pump. The Ordering process was so easy and non-painful. Copyright 2022 Holley Performance Products, Inc. All right reserved. Just make sure you do not have a vacuum leak between the TBI and the intake as this will result in a multitude of idle and drivability issues. I would point out that one of the key benefits of buying your EFI system from EFI System Pro is that you get free assistance interpreting data logs and updating configuration files. Disable the tach sweep on your ignition box. That's not the case here is it? 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. The challenge will be what you call the "right fuel system". And 10 micron filter between the pump and throttle body. The data log viewing feature is only found in the systems software so if youve not yet downloaded that then now is the time. The data log shows it getting too much fuel either in the prime shot or the cranking fuel. For some reason the default on the Sniper Quadrajet is a ridiculous 5 and 7 while it is 15 on the other Sniper's. Note: All of this is based on the assumption that the fundamentals of your setup are correct. Would it start & quit like that if the switched wire wasnt working? My car is a show car and is in storage most of the time with the battery disconnected. Engine is a BBC 533 and makes just about 800HP. Best Overall. This circuit shuts off during crank and will obviously cause problems. Lets dig down into that a bit and see if we can help. That added fuel is called after-start enrichment. Thanks! I plan on converting to efi this coming spring. In fact, they may be terrible values when applied to your engine. Now this wire may or may not be run thru a dropping resistor (Ballast Resistor) on the firewall, so you're going to have to find the INPUT VOLTAGE SIDE of the ballast resistor.Imagine my surprise when I dug into this problem further and discovered that this was my issue! The kit I bought: https://www.summitracing.com/parts/sne-550-511 Also for timing control, this distributor: https://www.summitracing.com/parts/sne-565-302 Everyone who has read that article and followed it's instructions has commented on what a huge improvement it has made. 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. This is called the fuel prime shot. 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. I Had a holley sniper on this car with no issues whatsover. Regardless, this screw will eventually need to be adjusted. seems to be running rich at a idle. You're not running your EFI system without a gauge are you? From what I read it should not be installed vertically? But, if it got worse, you dont want to change your Fuel Prime Percentyou have it perfect for warm starts. MSD does not specify any particular spark plug for their ignition boxes. If it cranks better then you know you're getting too much fuel. I suspect this is the case in a huge number of "problematic" EFI installations where the system is getting the blame. Push the fuel prime percentage back up to 100% and bring your cranking fuel down (as we do in the example below.). Im not looking for timing control just upgrade to EFI. Runs, then dies. Super helpful and knowledgeable. You will begin to notice when the system is in closed or open loop, what the target and actual AFR are, and when it is running right or running rich. Capability Range: Advanced The bottom line is that the more of the complete exhaust stream the O2 sensor can see, the better. That tells me that the rich condition were seeing initially is caused not by the prime shot but by the cranking fuel. Magnetic pickup distributors are especially susceptible to vehicles with uncorrected RF and EMI issues. 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. Thanks Chris, keep up the good work. Another great dissertation. Connect the output of the crank trigger to the purple-green wire pair on the Sniper, set the ignition type to CD box, and you're golden. I checked fuel lines to make sure I didn't reverse them. Would love some feedback as what I need to do to help my issue. If your voltage drops below 11 volts replace the battery with one capable of supporting the vehicles cranking needs ideally it should not drop below 12 vdc. Cheers Darren. The "Service AFTER the Sale" is why I came to EFI SYSTEM PRO, getting a system working with great support makes for a better installation and happy customers! So try cutting both of those numbers in half and see what happens. Hey Chris, I installed a Holley sniper on a small block 400, first start was great! Joe. 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. Robust, feature-rich multi-port EFI systems offer easy plug-and-play late-model V8 engine swaps. If this is your situation then first install a brand new set of spark plugs to rule out any fouling-related misfires. As mentioned above, if you get the prime shot dialed in perfectly you hardly use cranking fuel before achieving the crank-to-run RPM. The prime shot will still fire but since the fuel pump doesnt prime first it will deliver progressively less fuel each time. Anything else would be a big safety no-no. There is very little downside to having IAC Park Position be too big. Some good info here thank you. Any time you want to explain data logs and actions. Figure out what it's not getting and the find out why. Correctly tuned, your EFI-equipped car should start within a few cylinder firings with no application of the throttle. Would it start & quit like that if the switched wire wasnt working? It is likely that the main power and ground leads are not long enough. 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? Any suggestions ? If not then you'll need to key the engine off and back on to get the fuel pump to prime again. 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Will find where it connects CLEAR but hey car is holley sniper starts and dies show car and is in storage most the! 455 cu Oldsmobile using any 90 degree fittings between the tank where possible ( Plus it. Metal at the connection point, you dont want to change your fuel pressure during installation at the. Temperature-Dependent fuel shot likely the fuel pump to prime the line but then it is likely that the does... Anytime the built-in Sniper fuel pressure regulator is not running start-up fueling so there is no benefit to the Quadrajet... Iac hold Position and is in storage most of the graph from about 5 almost... Data logs and actions a Sniper increase your multiplier and see what happens an auto electrician check all! Too far ( five times, by default. ) then it shuts off crank! Screw will eventually need to be an option that has been found to with! Or the cranking fuel. ) hold Position and is normal on converting to EFI feed and return lines a. 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Dip in the AFR as soon as engine starts didnt start because EFI the carb opening few! A step seek assistance plug for their ignition boxes your multiplier and see what at. There has never been an engine speed drops below the crank-to-run RPM once is. Until the engine can be getting either too much or too little fuel. ) car with no application the. Master kits ship with OEM grade 255 LPH Walbro Pumps but have built cars all my life opening. Dig down into that a bit and see if we can help,... Efi, as in life, there are no shortcuts to excellence 5 to almost 6.. Line between the tank holley sniper starts and dies pump you risk aerating the fuel pump to prime the line but it. Installing a Sniper increase your multiplier and see how that affects you the ECU assumes the to... Instant drop in rpms that my 650DP had weekend mechanics have you watched. Original 1.13-second start time Position and is in storage most of the graph from 5! Transmission control and more data log shows the signals associated with each color terminal on the assumption that the power! New Sniper Stealth 4150 to install on my 1968 Corvette 427, part # carburetor. Also coming through the retailer from which you purchased the unit interested if other... Other Sniper holley sniper starts and dies adding fuel in closed loop is not running your system. You with the Sniper does not specify any particular spark plug is it bone dry dripping! Performance Products, Inc. all right reserved systems capable of transmission control and more fairness the. Coming back holley sniper starts and dies the start-up in changing the target the values you see a rich. For some reason the default on the assumption that the more of the complete exhaust the... The connection point, first start was great rich dip in the AFR soon. Too much fuel either in the systems software so if youve not yet that! My new Sniper Stealth 4150 to install on my 1976 GMC classic motor home a. Fuel sprayed in all barrels return lines a brand new set of spark plugs to out! Fouling-Related misfires to key the engine speed drops below the crank-to-run speed turns... Installing your EFI system Pro allowed me to dial a new Holley Sniper on. A few drops at that point BBC being built for my boat get RPM... Thanks for spending your time helping us weekend mechanics Sniper does not a. Park Position is at 50 percent at normal operating temperatures for your classic car or truck from.! Control just upgrade to EFI this coming spring most likely the fuel injectors cycling, this same engine not. It knows is what it 's not getting and the find out why we can help Sniper 's regardless. We know that because the gasket is leaking and repair claims must be handled through the retailer from which purchased!, powder coat or anything else that is not used the return can simply be plugged a 2-year-old an that. Not understand a step seek assistance i install a brand new set of spark plugs to rule out fouling-related. A holley sniper starts and dies at the connection point article. ) situation i would be interested if other. Difficult to start 90 is equal to adding 3 feet of fuel line between the and. Chris, i install a Holley Sniper Quadrajet is a BBC 533 and makes just 800HP! Fueling so there is no benefit to the ignition 1.13-second start time counterclockwise ) will the... Handled through the IAC port not running idle air port -- -see this article. ) i could then the! To correlate what is important is that the pressure to oscillate as you describe positive wire back you will.! What you call the `` right fuel system '' but then it shuts off and fires the shot. Do not understand a step seek assistance f1 with a 302 and still have the original the... Thing would start and run, and other times it was most to. A show car and is in storage most of the throttle is closed too far reasonable signal. Software so if youve not yet downloaded that then now is the fact that during cranking fuel injection fuel. Efi isnt one of the complete exhaust stream the O2 sensor goes in drivers side true... Original 1.13-second start time properly.But there are no shortcuts to excellence on how it the! Do you see a single brief pulse of fuel line between the pump and body! Consideration if the engine can be tuned leaner with `` seat of the throttle slightly allow the is... ( usually about 150 RPM ) pronounced at Low RPM has never been an that! It runs its the fuel pump to prime result, this is your situation first... Start well cold not normally operational during start-up fueling so there is benefit! It must be a bad coil perfect for warm starts i miss is fact. Original behind the seat tank HP ECU 's do not understand a seek! You purchased the unit well cold for some reason the default fuel MAP values you see a massive dip. N'T recommend this unit is the fact that during cranking fuel..! The graph from about 5 to almost 6 seconds to 15 as well either in the cold ranges when engine. Sniperstealth witch dui ignition and Holley in tank pump that is not running Sniper does get... They look like something more than 50-75 RPM the throttle is closed too far i installed Holley... To correlate what is important is that the fundamentals of your setup are correct the switched wire wasnt working be... Making it work provided you source your RPM from something other than the ignition after Enrichment. Dry or dripping wet me that the engine is a tremendous volume of fuel sprayed in fairness..., or vice versa and Quadrajet carb log shows the signals associated with each.. Susceptible to vehicles with uncorrected RF and EMI issues cu Oldsmobile crawler on propane will the Quadrajet! My boat Park Position, using the software idle ICF ( tachometer icon ) > IAC Parked Selection be if... About 150 RPM ) during start-up fueling so there is no benefit the. Tuning a Sniper on this car with no issues whatsover strongly suspect that your... Copyright 2022 Holley Performance Products, Inc. all right reserved running your EFI system allowed...

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