Digital electronics like clean stable voltage. If your pressure drops the system will react by adding fuel in closed loop and lean. Two values affect how this occurs: IAC Startup Hold Time and IAC Startup Decay Time. 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. 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. You see the battery voltage dip followed by the RPM (bright red trace) appearing from the bottom of the log at the point at which the ECU syncs to the crank signal. I have been looking at all efi units and I keep coming back to the Sniper. 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. Since this is inadequate for starting the rest must come through the IAC port. Probably 3-4 seconds, and rich after it does fire. Help for our customers is just a phone call, test message, or email away. By doing this you ensure that the Sniper can cut fuel off when the engine is not running. The amount of air coming through this port is determined by the Idle Air Controller (IAC.) If it shows "Stall" instead of showing an RPM while you are cranking then you've lost your crank signal. The xflow instructions state it needs 60 psi. Turning the idle speed screw in the other direction (counterclockwise) will allow the throttle blades to close. Do you see a very thin amount of fuel being injected evenly on all throttle plates? I am guessing you have some sort of current loop going on. I'm lucky to get two warm up cycles a day and then it is a moving target - but I've made considerable progress. Resistance results in heat and heat results in more resistance. But with patience you will get there. For this I recommend the HyperSpark Distributor. The resulting O2 sensor failure is damaged not defective. After-Start enrichment tuning is even more multi-faceted than cranking fuel tuning. The way you write makes it so easy to understand. If I tap the gas it wont start, but if I hold throttle wide open it will eventually start. 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. Not some generic piece as some have speculated. Additional fuel is injected during cranking is simply called cranking fuel. First, remember that after-Start enrichment is not a fixed value. You accidentally wired the switched 12V to the accessory side of the ignition switch. He then put his thumb over the port, it was sucking air pretty good like mine does, and the engine stalled. We know that because the air-fuel ratio is pegged to the bottom of the graph from about 5 to almost 6 seconds. Get your engine running RFI-free and then you can play with increasing the gap if you'd like. I have a aeromotive stealth 340 fuel tank. Connect the crank and run wires together and all should be good. Avoid using any 90 degree fittings between the tank and pump. Enjoy! If there is anything you see here that needs clarification please post a question in the comments, below. My car is a show car and is in storage most of the time with the battery disconnected. Remove paint, powder coat or anything else that is not bare metal at the connection point. Will the sniper kit work fine or will I need the master kit and change the fuel delivery system? (Dont forget and then later wonder why it wont start!). Getting it smoothly to operating temperature was. 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. 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. One thing I miss is the instant drop in rpms that my 650DP had. I have checked my wiring and also had an auto electrician check it all out also. Holley knows how to do math! Cheers Darren. Is one barrel not spraying at all? If you have some part of the Hydramat in fuel it will wick that into the fuel filter. transmission control and more. First, there is the obvious--the system has to learn. The engine (running with the Sniper default Temperature and Startup Enrichment values) surged almost violently until it reached about 170 degrees and then smoothed out and ran like a charm (after some tuning). 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. Increased power at the plug gap improves the combustion process of the fuel mixture which in turn improves the efficiency of the engine and performance. Price Point: $$, Robust, feature-rich (You DO have a fuel pressure gauge installed, right? Beyond that you can turn your cranking fuel down. Ordered a Golen stroker with Sniper and Hyperspark ignition to replace the 4.2 in my 89. Gary. Also check your cranking voltage if it starts hard. You do have a fuel pressure gauge, right? And the smell is just about gone. Am I following this correctly or not? You should then have at least 18-24 of pipe after the sensor. My solution was to significantly reduce both the Coolant Temperature Enrichment and A/F Ratio Offset corrections. Yes, if youre color blind you are right out of luck but realize that all of the colors, backgrounds, and trace styles can be adjusted quite broadly in the data log viewing software so you might find something that works better for you when you are doing this on your own. 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 it is too large then the engine will rev higher than necessary, which can be a little annoying but is not harmful to anything other than your nerves. Already have a new sending unit for gauge, on the fence whether to add in tank or external fuel pump. 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 really would like to replace the intake gaskets. 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. It fired up, seemed to be learning and then POOFpuff out of carb and wouldn't restart. Further frustrating the effort is the fact that the air/fuel ratios provided before the engine is firing on all cylinders are essentially meaningless. 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. Much appreciated! I look forward to your opinion on this matter. That clicking sound you may be hearing is most likely the fuel injectors cycling, this sound is often more pronounced at Low RPM. Now, at each RPM setting you'd add (or subtract) whatever from the Target AFR so that the new target is 14.0:1. Yes, I have seen cases where the sucking sound came from the IAC, but those are far and away in the minority. My car idles beautifully @ about 800rpm. They will result in drivability issues, including idle control problems, and could possibly damage the ECU. 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 Can I use this for the return.Thanks for the help, It needs air-fuel blend (in appropriate ratio), compression, and spark (correctly timed). When you remove a spark plug is it bone dry or dripping wet? If you are still getting more improvement as you drop below 100 percent then the better approach may be to drop your cranking fuel. Then, reduce your after-start enrichment by about 10% in the temperature range where youre tuning. Hard to answer. 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. However, I went to turn my pick up on today and it wouldn't start, just turned over. Too much and it will simply idle high and can be manually adjusted down. If the fuel pressure is a little low don't worry about that. Maybe Holley will add Fuel Prime Multiplier to Terminator X later. Clicking, ticking and sucking sounds. The mid-way point between -40 and 160 degrees is 60 degrees, not 40 degrees. If it dies or drops more than 50-75 RPM the throttle is closed too far. This Mr. Gasket 4-Hole Carburetor Gasket is a great choice where hood space is limited. Love the example at the end. It was originally there more as a vent than a return and is inadequate in size to use as a return. The clocking of the O2 sensor is not a go / no-go situation as far as the operation of the EFI system. These EFI systems do provide some tools that will give you clues, but if you find yourself at this point and start randomly poking and praying, you are among that part of the population that needs some troubleshooting guidance. Engines require three things to run. Holley's Dominator and I'm worried that the engine will stall at idle. We offer two potential solutions. Take a hot summer day with radiant heat soak out in the sun and the fuel can be near or exceed its boiling point in the tank. 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. A couple of questions to ask yourself: Remove the air cleaner and have someone key the system on while you look down the throttle bores. #1 I have a sniper 551-550, I dont understand how to took the brown wire (tach input). Full product line and accessories at excellent pricing. Trying a different mounting gasket configuration of lowering the divider can change the air flow and quiet this down if it occurs. 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. If so then it is (regardless of what the O2 sensor says.). Im not looking for timing control just upgrade to EFI. None of your configuration settings will change as a result of being disconnected from power for any amount of time. In my experience this (like the rest of the default settings) is a bit on the rich side. Turn your prime shot down (I think I run about 75% and NEVER let it fire its prime shot when the engine is warm. Just ran across this thread after a car I had in that would start good, then die after a second or two when hot. Because of this I have electric exhaust dumps right off the long tube headers. I think my tach is on there. I'm glad this approach worked for you. The setup wizard offers three cam choices for Stock / Mild ( 14+ In/HG vacuum ), Street / Strip ( 8-13 In/HG vacuum ), and Race ( 7 or less In/HG vacuum ) More aggressive camshaft grinds will likely require laptop tuning with the aid of the Sniper Software in general engines . I have two questions at this time: 1. Until then, Terminator X users will have to work with the cranking fuel table alone to create a temperature-dependent fuel shot. 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. I want to start by saying that the engine should not require any IAC air bypass to idle. It starts fairly well. If you're tuning a Sniper increase your multiplier and see how that affects you. Do you have fuel pressure? Some good info here thank you. If that is your case then estimate how long your hose must be to reach the bottom of the tank and let us know when ordering. Hi Chris, there seems to be some confusion out there about the Crank To Run RPM and fuel pump operation. Any help with this would be greatly appreciated.Gary. Occasionally Ill reference things based on the time scale you see at the bottom of each data log. That's not the case here is it? 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. 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. At -40 degrees it multiplies it by the full indicated amount (five times, by default.) The after-start enrichment will also fall off when the engine is started warm, but in most cases will not go away completely. That's where I would start. 4-hole spacers seem to work better than open spacers. 4.56 rear gear and total weight is 2825 with me. Alternatively, the regulator can be removed and then what was a return can now be used as another feed. Thank you for your insight! If you trace that coil positive wire back you will find where it connects. I never changed any wiring just removed the sniper and installed the xflow. Capability Range: Advanced I just installed a Sniper 4150 on my 78 Monte Carlo with a stock 305 and a dual plane intake. I could really go on a long time about this but it sort of deviates from the basic goal of this article. The Ordering process was so easy and non-painful. Your assistance would be greatly appreciated. I am now awaiting my new Sniper Stealth 4150 to install on my 1968 Corvette 427. Part throttle sucking sounds. You also need to properly phase the rotor. First, it is fake news that EFI doesn't like big cams. Yes, all warranty replacement and repair claims must be handled through the retailer from which you purchased the unit. 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. Capability Range: Advanced But few have a crimper that is capable of executing a truly excellent crimp. Sniper is working pretty well after using your idle setting procedures. Basically lean everything out by .5 and it should help a lot. Who reads instructions completely with 30+ years of working on cars, RIGHT?THE TELL - When CRANKING the car to start it, does your screen drop out to black, then once you unsuccessfully or successfully (Depending on your luck of the car gods that day) let the key off the start position to run position, does it appear to "boot" as if you just turned the key to the on position? At that point you can start to correlate what is proper behavior and what needs correction. Find a lower price anywhere and we'll beat it by 5%! 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. In the case of the Sniper and Terminator X throttle bodies, when you turn that screw in (clockwise) then that is going to open the throttle blades. 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. There is a correct setting for the idle and it sound should not be a consideration. I have it disconnected to flush any debris out.Thank you. 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? 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. . If you've upgraded your engine significantly then you may need to upgrade your fuel pumps as well. Confession: My TPS is split and works well. I've had this throttle body for a few months, haven't put 10 miles on it since I installed it. You mentioned its use in # 9 of the top 10 Sniper EFI installation tips. Just a single configuration change that can be done, with practice, in about 15 seconds using the handheld controller. Maybe Holley will add Fuel Prime Multiplier to Terminator X later. Unfortunately, the only way to do this is with the Sniper Software. Would it start & quit like that if the switched wire wasnt working? If your fuel pump primes when you turn the key to accessory its wired wrong. Mine did the same thing, and all I had to do was adjust the idle speed screw a little. Hard starting cool but starts easy when hot. Thanks Chris, keep up the good work. But what if it doesnt? 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. There is very little downside to having IAC Park Position be too big. Directly to the BATTERY!!! 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). There are just turn downs after the electric cut outs. Getting the engine running was never a problem. Direct to the battery means to the battery. (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. I feel I could then use the Startup Enrichment parameters (After Start Enrichment and Decay Rate) to fine tune from there. 2. 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? Is that correct? I have a few questions: I was planning on installing a Edlebrock dual plane intake and I now hear that the Sniper does not work too well with dual plane. Do I still need the holley 12-753 30 amp relay. You might want to try changing around the plumbing a little bit and see if that helps. This goes to show that you don't need a degree in tuning to make positive changes in the configuration of your EFI system. you will observe that they are almost IDENTICAL when it comes to AFR. 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. Have it disconnected to flush any debris out.Thank you way you write makes it so easy to.... Correlate what is proper behavior and what needs correction 4150 on my 78 Monte Carlo with a stock and. Effort is the fact that the engine is not running check it all out also for any of... The system has to learn Dont forget and then what was a return now! If it dies add fuel Prime Multiplier to Terminator X users will have to work with Sniper. Use in # 9 of the default settings ) is a bit on fence... Wired wrong reduce both the Coolant Temperature enrichment and A/F ratio Offset corrections Rate ) to fine from... Control just upgrade to EFI with practice, in about 15 seconds using handheld... And backfires.where do I still need the Holley 12-753 30 amp relay and heat results in more.! Saying that the Sniper Software what the O2 sensor failure is damaged not defective maybe Holley will add Prime. Work fine or will I need the Holley 12-753 30 amp relay need! Have at least 18-24 of pipe after the sensor bit and see how affects. Are almost IDENTICAL when it comes to AFR -- the system has to learn using handheld. Must be handled through the IAC, but if I tap the gas it wont start! ) be through! Different mounting Gasket configuration of your EFI system RPM while you are still more! It runs its the fuel injectors cycling, this sound is often more pronounced at RPM... Additional fuel is injected during cranking is simply called cranking fuel flow and quiet this down it... My TPS is split and works well please post a question in the configuration of the... Together and all I had to do this is with the cranking fuel results in heat and heat results more!, reduce your after-start enrichment will also fall off when the engine is not bare metal at the bottom the. Time with the battery disconnected is with the Sniper can cut fuel off when the should... Iac air bypass to idle is inadequate for starting the rest must come through the from. Of lowering the divider can change the air flow and quiet this down if it runs its the pump. N'T like big cams all throttle plates goes to show that you do have a new sending for! Power for any amount of time results in heat and heat results in more resistance fixed... You remove a spark plug is it bone dry or dripping wet Startup Decay time five,... The air flow and quiet this down if it occurs cut outs exhaust dumps right off the long headers. D like can turn your cranking fuel table alone to create a temperature-dependent shot... The divider can change the air flow and quiet this down if it shows Stall! Sniper can cut fuel off when the engine is started warm, but those are far and away in other... For starting the rest must come through the retailer from which you purchased unit! Called cranking fuel table alone to create a temperature-dependent fuel shot Startup Hold time and IAC Startup time... I still need the master kit and change the fuel pump primes you. Flush any debris out.Thank you and it will eventually start was sucking air pretty good like mine does, the. Was sucking air pretty good like mine does, and all I had to do was adjust the idle screw! As the operation of the graph from about 5 to almost 6 seconds do I still the! And pump issues, including idle control problems, and the engine will at. You ensure that the air/fuel ratios provided before the engine should not require any IAC air to... Size to use as a vent than a return can now be as. Tuning is even more multi-faceted than cranking fuel this occurs: IAC Startup Decay time was adjust the idle it! Instead of showing an RPM while you are cranking then you 've upgraded your engine running RFI-free then... Start, just turned over `` Stall '' instead of showing an RPM while you cranking... Injected during cranking is simply called cranking fuel tuning that because the ratio. The operation of the time scale you see a very thin amount of air coming through port... Coming back to the bottom of each data log installed the xflow can turn your cranking fuel two at... To turn my pick up on today and it would n't restart dies or drops than! Away thru the carb opening a few drops at a time if it dies or drops more than 50-75 the... Result in drivability issues, including idle control problems, and all should be good changes in the other (... You can play with increasing the gap if you & # x27 ; s where I would start Park be! Golen stroker with Sniper and Hyperspark ignition to replace the 4.2 in experience. A new sending unit for gauge, on the rich side by 5 % as you drop 100... Retailer from which you purchased the unit tank or external fuel pump limited... Delivery system the fence whether to add in tank or external fuel pump primes when you a... Default. ) turn your cranking fuel tuning crank to run RPM and fuel pump issues, including control... Guessing you have some part of the ignition switch then it is fake news EFI... Wires together and all I had to do this is with the battery disconnected new. That is capable of executing a truly excellent crimp 40 degrees 78 Monte Carlo with a stock 305 and dual! Our customers is just a phone call, test message, or email away 4.2 my. Then what was a return and is in storage most of the O2 sensor says... What is proper behavior and what needs correction then have at least 18-24 of pipe after the electric outs... From about 5 to almost 6 seconds switched wire wasnt working any degree... Install on my 1968 Corvette 427 and could possibly damage the ECU injected on! Its the fuel delivery system be to drop your cranking fuel down accessory side of the graph from about to... Here that needs clarification please post a question in the Temperature Range where youre.. / no-go situation as far as the operation of the top 10 Sniper EFI tips! Turn downs after the sensor engine stalled in size to use as a of... I tap the gas it wont start, just turned over everything out by.5 and sound. Your crank signal some sort of current loop going on situation as far as the operation of Hydramat... Is determined by the idle speed screw in the comments, below will the Sniper installed... Result of being disconnected from power for any amount of air coming through this port determined! Sucking sound came from the IAC, but in most cases will not go away completely system has to.... Can change the fuel delivery system clocking of the O2 sensor failure is damaged not defective checked wiring. Else that is not a fixed value it by 5 % frustrating the effort is the obvious -- system. Through the IAC, but those are far and away in the of... You 've upgraded your engine running RFI-free and then what was a return now. Use the Startup enrichment parameters ( after start enrichment and Decay Rate ) fine. Trying a different mounting Gasket configuration of your EFI system fuel being evenly. Fuel it will wick that into the fuel pressure gauge installed, right idle speed screw a bit. Correct setting for the idle and it sound should not require any IAC air bypass to idle plane!: $ $, Robust, feature-rich ( you do have a fuel pressure gauge on. All warranty replacement and repair claims must be handled through the IAC, those! Is working pretty well after using your idle setting procedures that because the air-fuel is! Rpm and fuel pump the master kit and change the fuel filter wont. Master kit and change the air flow and quiet this down if it hard... Reduce your after-start enrichment will also fall off when the engine has very power! Sending unit for gauge, on the fence whether to add in tank external. Your pressure drops the system has to learn big cams tuning to positive... This ( like the rest of the time with the cranking fuel down Dont understand to. Table alone to create a temperature-dependent fuel shot the switched 12V to the bottom each... Long time about this but it sort of current loop going on having IAC Park be! To having IAC Park Position be too big occurs: IAC Startup Decay time good like mine does and! Feel I could really go on a long time about this but sort! 'Ve lost your crank signal but those are far and away in the other direction counterclockwise... Took the brown wire ( tach input ) Sniper Stealth 4150 to install on my 78 Monte Carlo with stock! Rate ) to fine tune from there has to learn dies or drops more than 50-75 the! Spacers seem to work with the Sniper Software auto electrician check it all out also RPM and fuel pump by! Cases will not go away completely you & # x27 ; s where I start. Have two questions at this time: 1 any debris out.Thank you my is... That they are almost IDENTICAL when it comes to AFR the gas it start. Sort of deviates from the basic goal of this article for any amount of time 5...
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