Also there are times when I am working on the car, I have the battery disconnected. First, it is fake news that EFI doesn't like big cams. I just wanted to list out some things that you should be looking for if you find yourself stuck here. 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. Your engine will be dependent on cranking fuel entirely. 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. If the fuel pressure is a little low don't worry about that. The Del City Time Delay Relay is pinned just like a normal relay. But never ever forget there is a second learning going on--your own. We offer two potential solutions. Did you hear the fuel pump run at key-on? However, I went to turn my pick up on today and it wouldn't start, just turned over. Great article. So my question is how do I get the IAC motor to close and create less air intake to eliminate the noise? you will observe that they are almost IDENTICAL when it comes to AFR. 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. Latest Articles. The clocking of the O2 sensor is not a go / no-go situation as far as the operation of the EFI system. Bolt-on carburetor style EFI for your classic car or truck. First, don't get too worked up about the flashing yellow and red values. Does pressing the throttle slightly allow the engine to start. If so is there a way to connect to a standby auxiliary 12 volt battery to the Sniper to protect the information?Many thanks,Louis. 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. Air is not just coming into the engine via the throttle blades. Free ground shipping regardless of order size! Thanks. In most cases this is at the fuse block but in a few it is at the ignition switch itself. Hard to answer. He then cycled the key off then back on again and TPS was back to 0 and the idle was back down to around 800rpm. superchargeddrt Well-Known Member Joined Aug 24, 2009 Messages 2,420 Reaction score 1,102 Top 10 Sniper EFI Installation Tips from Holley's Tom Kise, Quickfuel 4-hole 1/2-inch Phenolic Spacer. I just moved it to the ignition terminal on the fuse block and voila, it ran. There must be an option that has been found to work. 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!! 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. You're not running your EFI system without a gauge are you? This includes: Finally, while many of these tuning steps can be performed using the handheld, youre working in the dark if you arent using the systems data logging feature to tell you whats going on. offer easy plug-and-play If it does not idle down your throttle is open too far or you have a vacuum leak. The switch for the starter is very temperamental and connects and disconnects easily so I would like to switch it to just a flip on option Ford Mechanic: Gary Ok, so now your fuel pressure gauge shows 50 psi or so? Third is the truth that every engine has its own preference on what it likes for startup fuel. And it may have improvedor it may have gotten worse. The default for these systems is 400 RPM. Don't let that get the best of you. The Sniper ships with an OEM grade Bosch O2 sensor. 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 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! If I go that far I have the option of replacing the intake, again, your thoughts? 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. In most cases you just hit the key at that point and it's happy dance time. (Ive written another article that includes one technique forsetting your idle speed correctly.) My car is going on the dyno for final tuning next week. Already have a new sending unit for gauge, on the fence whether to add in tank or external fuel pump. idles good, runs amazing. A brief spray of fuel is injected before cranking. Nice catch, Ken! Connect the crank and run wires together and all should be good. Not perfect but not bad. I'm all eyeballs! Hello, . So if the +12 Volts "goes away" during the crucial start cycle the EFI ECU is essentially "Brain Dead" seemingly at this point. Last time it ran was last week and it ran fine but I believe I ran out of gas or was close to running out of gas while idling in my driveway. I see recommended plugs are resistor type. Is the sniper compatible with my distributor? Do as I Holley says? Start the motor with the air cleaner off and the chock butterfly held open if it stays running its the chock. If you don't show any fuel pressure then fix that. 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! Thanks, Steve! The xflow instructions state it needs 60 psi. Another great dissertation. You can find that here. 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. The strong exhaust smell during this time indicated a very rich condition. Yes, I have seen cases where the sucking sound came from the IAC, but those are far and away in the minority. One of the most common causes of poor idle is improper O2 sensor placement or trying to run closed loop at idle with a cam that exhibits quite a bit of overlap at low RPM. 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. I really want to go EFI this year. I want to start by saying that the engine should not require any IAC air bypass to idle. 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. ), In my ongoing quest for knowledge prior to installation, I have another question. 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. We see a nice improvement in that big fuel dump as the engine starts running (between 3 and 4 second mark.) But with patience you will get there. (Dont forget and then later wonder why it wont start!). I'm worried that the engine will stall at idle. First, remember that after-Start enrichment is not a fixed value. Further, your idle speed screw should be set so that your IAC only needs to be open a couple of degrees to maintain the target idle when the engine is fully warm and experiencing no load from transmission or accessories. I hope to do more articles similar to this so stay tuned! A tube type 90 is equal to adding 3 feet of fuel line between the tank and pump. Resistance results in heat and heat results in more resistance. late-model V8 engine swaps. Had issues so Im now going with the Holley in tank pump. If you have any exhaust leaks between the combustion chamber and 18-24 after the sensor you are going to have problems. I look forward to your opinion on this matter. That's not the case here is it? We do see a massive rich dip in the AFR as soon as engine starts. Thanks Chris, keep up the good work. I think my tach is on there. My car is a show car and is in storage most of the time with the battery disconnected. And the less correction you do until you understand that---the better! Does it matter if O2 sensor goes in drivers side with true duals?Thanks for spending your time helping us weekend mechanics. Good luck! You just have to go one direction and see if things improve or not. Not all 12 volt switched sources in the fuse block of a 55 year old car do this! Enjoy! sniper Installation 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! Proper plug readings would need to be done to confirm if you can go any leaner WOT tuning. 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? Getting the engine running was never a problem. Why? I figured it would be minimal. This is most often a result of air flowing through the IAC port related to the IAC hold Position and is normal. While I reference the target AFR here I purposely don't call out the value. Because all it knows is the specified system pressure, which doesn't exist at this point. Do you see a very thin amount of fuel being injected evenly on all throttle plates? Any help with this would be greatly appreciated.Gary. Since I dont want to add fuel where were already rich Im going to add a bit of After-Start Enrichment Holdoff. All times are GMT-6. I have checked my wiring and also had an auto electrician check it all out also. The x-axis is time, but it is true that the volume of both after-start and coolant enrichment is determined based on temperature (and certainly that temperature will increase as the engine runs, eventually eliminating any coolant modifier/enrichment.) Unfortunately, the tuning ease of a Holley also creates some tuning problems. Start by going after the fuel prime shotthe amount of fuel injected into the engine before cranking begins. Now were getting there. Except for drive-by-wire throttle bodies (which we wont discuss in this article), most throttle bodies are going to have an idle speed screw that sets how far the throttle blades are open when the throttle pedal is fully released. This is obviously an ongoing process. If you do not understand a step seek assistance. Ramp Decay Time: How many seconds the ECU will use to lower your idle to the target once it drops within the range specified by item 2.). I would add a 12v-switched relay to power your Sniper. While it may sound odd its not a defect and will not cause any drivebility issues. There should be 1 AWG or larger ground strap going direct from the battery to the engine. Runs, then dies. I trust you'll be using this new knowledge to speed up cold starts up there in Alaska. That helped. There should definitely be no power to the fuel pump from the fuel pump relay until the crank-to-run RPM is reached. If it cranks better then you know you're getting too much fuel. This is normally completely adequate. It should be installed in a manner that delivers returned fuel below fuel level. If you turn your key to run and the RPM on your tach sweeps you probably have an MSD 6425 digital 6AL or ready to run distributor with the 12V square wave tach output wire and you missed the part in the ignition system or distributors instruction manual that said you need to disable your ignition systems rev limit verification feature if you are running EFI. Turned ignition off & back on, cranked the engine and it started, ran for about a second & died, will not restart if you crank it again. 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. If you have RF and or EMI issues you need to correct them. The resulting resistance can burn up fuel pumps, wiring and relays. RPM Above Idle to Re-Enable Idle Control.You could simply drop 2.) Your thoughts?In your opinion, should I keep the factory cast iron intake or should I replace it with a more efficient one. You also need to properly phase the rotor. You see that the AFR trace is ar below the target AFR (pink trace.) Sure enough the pink wire DID NOT have voltage when cranking. If the pump has a restricted feed or is mounted above fuel level and has to lift fuel you Will damage the pump do to cavitation. 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. That added fuel is called after-start enrichment. I would be interested if any other users have experienced similar issues with their setups and their solutions. 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 you shorten the harness, not only are you likely to damage the sensor you probably just short circuited your ECU. I've gone through all the steps and cannot seem to solve the problem. The A/F Ratio starts at -1.0 and decays to zero at 140 degrees. I have a sniperstealth witch dui ignition and Holley in tank pump. When the injectors open to spray fuel the pressure might drop enough to allow a few drops of fuel to flow, but nothing near what you're going to need. #2 I have a return 1/4 pipe coming out of the fuel pump at the fuel tank. Capability Range: Moderate Sniper users take note: Always wait to depress the throttle to the clear-flood position until after you key on the system as the Sniper re-zeros the throttle position each time the system is keyed-on. Sniper is an exclusively throttle-body based line so it made sense to include it. 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.). Sometimes just moving a fitting or changing the length of a line is enough to confound the harmonic and make it go away. This helps ensure that any trash that might have been in the line somewhere is swept somewhere other than into an injector. Find a lower price anywhere and we'll beat it by 5%! Capability Range: Advanced 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. Terminator X Stealth Universal 4BBL TBI Systems, Actual fuel pressure matches what is specified in the configuration, Fresh spark plugs of the manufacturers specification are installed, Engine is timed and tuned for correct performance. Bolt-On EFI for your All it knows is what it sees in the pipe. As a result, this same engine may not start well cold. That's what the fuel prime is all about. Ive gotten my hot starts really dialed in, but I always get a longer crank than I like on the first cold start (usually 60-70 degrees ambient). Capability Range: Advanced You can feather it a bit so that it generally keeps the same shape but don't impact the cranking fuel up in your warm temp region. MAIN POWER AND GROUND need to go to the battery. Basically lean everything out by .5 and it should help a lot. Does the Sniper send power to the fuel pump after the initial prime shot below the Crank To Run RPM or does it not? Lets go back to 100% fuel prime and turn cranking fuel down in that region by 30% and see how that affects us. Nor can I really recommend that you split it as I have. 02/23/2023. In fact, they may be terrible values when applied to your engine. So go forward with your install confident with the knowledge that if you need help, EFI System Pro can provide it. 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. Therefor, -40 + 100 degrees = 60 degrees. 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.) 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. 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