holley sniper starts and dies

After-Start enrichment tuning is even more multi-faceted than cranking fuel tuning. Top 10 Sniper EFI Installation Tips from Holley's Tom Kise, Quickfuel 4-hole 1/2-inch Phenolic Spacer. I'm glad this approach worked for you. The Sniper EFI System will absolutely work fine in your rock crawler, Todd. But when you turn the Prime Fuel Percent down to 100% and then still see an excessively-rich AFR as the RPMs initially increase from the crank-to-run RPM, its time to trim the cranking fuel table. Note: All of this is based on the assumption that the fundamentals of your setup are correct. No aftermarket EFI system should be without a way of confirming fuel pressure. But I strongly suspect that is not the case. 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. FE 390 that currently has a Pertronix distributor with the Ignitor 2 module. O2 Sensor Mounting: The O2 needs to be mounted 6-8 after the merge in the header collector. But I suspect that's not the case here. Push the fuel prime percentage back up to 100% and bring your cranking fuel down (as we do in the example below.). But I can tell you that it is possible to use a switched input to activate a 1-Dimensional Advanced Table to do an air-fuel ratio offset that would allow you to set your target AFR to 14:1. But weve also introduced some leanness from 4-10 seconds. Your thoughts?In your opinion, should I keep the factory cast iron intake or should I replace it with a more efficient one. The sniper master kits ship with OEM grade 255 LPH Walbro Pumps. Not perfect but not bad. I have a 88 f150 302 with factory efi and dual tanks. Disable the tach sweep on your ignition box. Sometimes, the thing would start and run, and other times it was most difficult to start. offer easy plug-and-play "Wouldn't the prime shot be half (2.5x) at 60 degrees and not 40 degrees? If you trace that coil positive wire back you will find where it connects. The Ordering process was so easy and non-painful. 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. Hard to answer. 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. It appears to be in throttle body? is setting themselves up for unnecessary frustration. You can run resistor or non resistor plugs with the 6AL box. First, it is fake news that EFI doesn't like big cams. It worked fine with carb, hope someone can help. If the fuel pressure is a little low don't worry about that. This happens with some carburetors on dual planes as well. So you be the judge. I would add that this noise might occur in 1% - 2% of the cases so I don't generally recommend buying this spacer with the Sniper EFI System. (Dont forget and then later wonder why it wont start!). Resistance results in heat and heat results in more resistance. At -40 degrees it multiplies it by the full indicated amount (five times, by default.) Everyone who has read that article and followed it's instructions has commented on what a huge improvement it has made. Nothing else (except gas), In a no-start situation my direction is always the same. 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. Most import. 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. 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. Engines require three things to run. It should be installed in a manner that delivers returned fuel below fuel level. Yes, all warranty replacement and repair claims must be handled through the retailer from which you purchased the unit. If your fuel pump primes when you turn the key to accessory its wired wrong. 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. Don't be that guy. Where do I start looking for the solution? Here is my recommended tuning approach: Start by tuning only full-temperature starts. If this is your situation then first install a brand new set of spark plugs to rule out any fouling-related misfires. Do you have fuel pressure? Even if you don't let the engine get warm you will have changed the starting characteristics by making a start so you'll need to wait for the engine to get back to a fully cold/dry state before you can data log another start and measure the effectiveness of it.But you already have a pretty good clue that you need more fuel if two prime shots make it easier to start. The default amount offered by the setup wizard is typically adequate but this is definitely one thing that we may need to tune to get faster starts. i.e., 5x at -40 and 0 at 160. Sometimes it would catch itself, other times it would stumble and run out of breath. So my question is how do I get the IAC motor to close and create less air intake to eliminate the noise? Does it recover if you bump the throttle? Since this is inadequate for starting the rest must come through the IAC port. Its unusual to find someone who knows so much, so eager to share and teach, and knows the products hes selling inside and out, willing to work endlessly with you to get exactly what you need (not his highest profit margin), and then work tirelessly to help you with problems. to the same number as 4.) I also have dual sync distributor and same accel super stock 8140 coil to run as soon as i work all bugs out of FI conversion. 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. 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 Granted, car was not on but still seemed like a lot of fuel to be returning. 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. Can I get ready made tunes?Even with this problem it is by far the best fuel system I have owned. Great article. Copyright 2017 Cyberspace Automotive Performance, Inc. All Rights Reserved. If that works then try halving them again. And the less correction you do until you understand that---the better! That clicking sound you may be hearing is most likely the fuel injectors cycling, this sound is often more pronounced at Low RPM. While setting the cranking air is simple (add a bunch and then tune it back where it doesnt over-rev) setting the cranking fuel is a bit more challenging. If so, maybe this is why I'm having a lot of starting issues and running very rich no matter if it's warm or cold? 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 better option is to use a bulkhead fitting, hose-barb adapter, and convoluted PTFE hose that reaches the tank where possible. For this I recommend the HyperSpark Distributor. Ill check the coil and see if anything else is attached. I have purchased two sniper EFI with the MSD distributor kit. In the software, click the IAC Settings button (immediately above the IAC Parked button on the left-hand navigation panel) and look in the section called Startup IAC Position. If you have RF and or EMI issues you need to correct them. 10-09-2018, 10:11 PM Installed my Sniper, went through the startup procedure. 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. If you . That is pretty straight forward. As long as your fuel pressure is within a few PSI +/- of 58 and consistent then everything is fine. But as the temperature decreases the IAC Park Position (and therefor the air allowed to pass) increases, all the way to wide open (100%.). Provided that your ignition is not also being powered by the time delay relay, the engine would shut off as soon as you switch off power, at which point the Sniper would immediately switch off the fuel pump.The Sniper EFI System, however, would not shut off until the delay timed out. features . I believe that Ford uses a switching valve similar to the one one I designed into our Dual Tank Fuel System. Too much and it will simply idle high and can be manually adjusted down. You're not running your EFI system without a gauge are you? 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. Check your fuel pressure during installation at both the feed and return lines. Have a look at those. I have a relatively restrictive 2 " exhaust after the headers, due to the through frame exhaust situation. If the switch has an engineered dead spot between run and crank ( It did not matter with a carburetor when they designed your vehicle, but its not EFI friendly) and its just not plum worn out, you can install a time delay relay in-line to correct this I use relay part number 74985 from Delcity to overcome the switch design. 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. It seems to be going threw gas faster then it should. 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 ). Hi, I have a 1987 Firebird with 305 engine and Quadrajet carb. Direct to the battery means to the battery. Price Point: $$$. Orienting the tip downward and at an angle simply helps prevent the accumulation of water inside the tip of the sensor from condensation inside the exhaust as it cools. Not some generic piece as some have speculated. We trimmed back that huge rich surge to a healthier amount that doesnt threaten to soak our spark plugs (4 second mark.) 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. :-D. Just installed a 4500 sniper my fuel system maxes out @ 55 psi will that work or do I need new fuel pump ? But never ever forget there is a second learning going on--your own. Feed pressure should be knocking on 58 PSI and the return should ideally be zero, if the feed pressure is not correct, or if the return line pressure is greater than 4-5 PSI find and correct the restriction before proceeding. 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. 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. 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. Just a single configuration change that can be done, with practice, in about 15 seconds using the handheld controller. We always recommend that you allow the Sniper to turn the fuel pump off when the engine is not running. Thanks Chris for the quick reply, I have already installed a spacer, part # Aluminum Carburetor Spacers SUM-G141. What is important is that you understand what happens at this point. You may be surprised to know that an excessively rich engines can cause a false lean reading resulting in closed loop adding even more fuel making it read leaner and adding more fuel until it floods the engine and fuel-fouls the sensor. Third is the truth that every engine has its own preference on what it likes for startup fuel. Happy New Year! Need to add fuel pump for required pressure. Air is not just coming into the engine via the throttle blades. Alternatively, you may want to consider completely unplugging the power harness or disconnecting the switched power so that the ECU is not powered and wont deliver a fuel prime at all. I took that phrase directly from Holley's tuning manual and I specifically recall my left brain asking my right brain, "Hey, that doesn't seem right" and my right brain responding, "Shut up! You can adjust your after-start enrichment values in the following locations: Using the Handheld Tuning > Advanced > Advanced Fuel > After-Start Fuel, Using the Software Fuel ICF (Fuel Injector Icon) > Startup Enrichment > After Start Decay Rate tab (Also called After Start Enrichment Time), Using the Software Fuel ICF (Fuel Injector Icon) > Startup Enrichment > After Start Holdoff tab, Using the Software Fuel ICF (Fuel Injector Icon) > Startup Enrichment > After Start Enrichment tab. Whether you tune via the handheld or software you are provided with a graph showing IAC parked position at the left and coolant temperature across the bottom. Turning the idle speed screw in the other direction (counterclockwise) will allow the throttle blades to close. 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. Is this normal? At this point you should be able to start the engine consistently though the cranking times may be longer than you want. Thanks. Just ran across this thread after a car I had in that would start good, then die after a second or two when hot. You need to run resistor plugs and resistor, non-solid core wires. Beyond that you can turn your cranking fuel down. I am having a 2 572 BBC being built for my boat. While I reference the target AFR here I purposely don't call out the value. 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? Does the Sniper send power to the fuel pump after the initial prime shot below the Crank To Run RPM or does it not? Is the Sniper EFI system rev-limiter capable. Here is where the denial starts. Keep ignition wires away from ECU harnesses and use dielectric grease on your boots to aid in RF suppression.

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