The second thing to realize is that even after you get it just right, you need to keep an eye on the IAC number and reset the idle if it gets outside the 2-8% range when idling when warm. I think that a great number of the challenges that Sniper EFI System Owners face are brought on themselves by getting into the control settings before the system has really had a chance to learn. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. first attempt but as it tries to idle down to the target RPMsit can never even If you feel you have no other choice but to run a Sniper and stand-alone controller then you can give this a try. I am at the point where I almost insist that every Sniper EFI System owner purchase one of these. Several good bits here. It is easily solved by installing a four-hole gasket or four-hole spacer (depending on your hood clearance issues.) The engine has 14: 1 compression ratio, we can not use gasoline. I've made all the adjustments, all the settings, and the IAC issue is driving me crazy. If that tested out okay then I can really guess that there might be some sort of intermittent, temporary RFI. Note: The IAC breather hole is the roughly 1/4-inch triangular hole that sits above and between the secondaries. :-). That will at least tell you something. I have it set at 650 and it idles anywhere from 590 to 700. If the regulator is working correctly and there is no restriction in the return line that should make no difference however.Sorry I didn't see this on the Holley forum. If the ECU has not spent some significant time learning yet, I'd recommend going back through the setup wizard and getting everything back to default. But if you can datalog the bog you can know much more precisely what is happening. During cruising at 30 miles and release the gas pedal the engine revs at aproximaly 1500 RPM and it won't drop. Please help. The noise changes sound with the throttle position. I am new to the EFI scene but want to learn. Next, reach down into the secondaries and push the butterflies closed. If I adjust idle screw out to get the tps to zero or even 1% the engine will not idle. Again, I would lean on that solution to let the vehicle drive/learn before you try to "fix" anything. If no air is passing (and the idle doesn't drop) then your IAC is working. It's all part of the adventure! It shuts off when coming to a stop sign, at any cruising speed and romdomly at idle in park but never when excelerating. An undersized or partially plugged fuel filter is a classic EFI installation mistake. When you key on, you will hear three distinct sounds: The ECU initializing the IAC, the fuel pump priming, and the injectors firing their prime shot. I ask because I'm using a PCV valve with my Sniper and have random idle issues as well. If the engine idles at 750 RPM with the throttle plates all the way closed and the IAC at zero then there is some sort of an issue. Remember that as an EFI System Pro customer you have access to me at any time via my cell phone. EFI parts, including the throttle body, and the problem persists.Please give me a hand. This page was generated at 12:26 AM. Yes, it will talk to you--but not with words. Cycling the power to the Sniper EFI would cure the problem, but not prevent it from coming back. I'll give the ". By the way your site and your accessory products are nice. Observing the temperature on the 3.5-inch handheld (only), wait for the temperature to achieve 160 degrees F. Once above 160 degrees, turn the idle speed screw so that the idle is about 50 RPM below your target idle speed set in step 1, above. I think you will find that it will learn its way through this. Find a lower price anywhere and we'll beat it by 5%! This is more of a bit of a reality check. Did you find this enlightening? I had a customer who struggled to understand that. RPM = 1200My slow gear I leave with 650 RPM, the IAC Position I leave between 5 and 6%, the Do you have a PCV on the engine? I was looking at a data log from my truck earlier this week and noted that at idle my IAC was zero. 680-700.I can't find any reason other than it looses where it is in the firmware with This is Intermittent meaning, I can run this test 5 times and IAC will function incorrectly 2 out of the 5 times. I would start by datalogging the situation and seeing exactly what your learn table looks like in the area immediately around the tip-in. I would disregard any correlation between idle control between the Stock and Street/Strip setups. However, I can't think of a single one that was because of low vacuum. The engine makes very low vacuum at idle. Coming home from work today it was much warmer and took a little longer due to traffic. (Do this while you are cranking.) Don't be surprised if one or the other is slightly open. All times are GMT-6. I have installed my Sniper and the car runs great. If you complete the process and find that the IAC is less than 2% at idle, repeat the process and use the set screw to make the RPM about 60 RPM below the target. If you go too high then the motor will not return to your target idle when you come off the throttle. Others might require 60 RPM. have noticed on the hand held is that Air/fuel Ratio rises to 20 +/- A/F and the I have adjusted many settings and eventually mess it up and go back to the original map. Capability Range: Moderate I can drive it a bit but pops through the throttle body when pulling out from a stop (4 speed) and sometimes in the exhaust out on the road. Intake has been on and off 3 times no change. lower until I turn down the set screw. Until the engine starts, the throttle only has one purpose: To detect you pressing it to 60%, at which point it shuts off the fuel injectors. I installed the Sniper on my 1978 Ford F-100 with a small block itself out and hold idleeventually stalling. Closed Loop Compensation rises to 100%, Do I just keep pushing it the same way to 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! I've read that a spacer with 4 individual holes will solve this, but after I installed the progressive linkage the noise went away!! No big deal, just time to re-adjust! That 60% (which is configurable) is known as the Clear Flood TPS. Holley Idle Air Control Motor Idle Air Control Motor Fits the Following Applications: Sniper EFI 90 mm, 92 mm, 102 mm Throttle Bodies Digital Pro-Jection Systems Avenger 4-bbl TBI Commander 950 Terminator TBI The Sniper resets the TPS to 0% each time that you key the system on. I have a Holley Sniper EFI with HyperSpark ignition. Give us a hand! is train the system or there is actually something wrong.I do love the system at The Tech Tips and discussions are also great! However, I did have another fellow who contacted me that claims he went through three units before he could get one that would talk between the ECU and the Monitor. That initial rev is going to be determined by your IAC Park Position. We are running a Sniper on my mates 355ci small block V8 & so far he is very impressed ! However based on your reply I connected the Fuel Pressure gauge and I recently bought the car with the EFI system on it. What would cause the idle to faulter like that? I also raised idle at Park a bit with the idle screw. I have seen a couple of videos on you tube of the same issue but they don't seem to have found the cure.I hope it is not a computer problem as I have already replaced the entire system because of another problem. It drops about 200rpm when clutch engages. The first thing I'd do is check your fuel pressure with a gauge like this. These aren't generic newsletters either but instead personalized emails. The only way to do this is by installing a mechanical fuel pressure gauge. I've not heard of any others with this exact issue so I don't think it is a common problem. If the engine will after the 4 seconds that the IAC kick drops off then it's not really going to help.At any rate, it costs you nothing to advance the ignition and see if that doesn't improve the idle, right? By the time I was near home, the idle in Park was 1050, IAC 0. I installed a sniper efi system on my 1969 Camaro. Your closed loop compensation is adding a full 50% fuel. And since they really had an insanely-tight monetary and real estate budget in the Sniper EFI System, it is unlikely that the added something that wasn't absolutely necessary--and then forgot to use it..And you are spot on about the little Earl's gauge with optional -6 AN port. Your suggestion to remove the PCV valve is just for diagnosis purposes, right? back upthe RPMs shoot up to anywhere between 1500 and 2000 and they will not get These are "transitional" cells, and you really have to make the effort to learn in these areas of the map. )Since this isn't a consistent issue with all Snipers that tells me that different IAC settings tend to make the whistle. I emphasize "and" because the transmission controller manufacturer I used had the TPS ground terminated within the harness to the unit's main ground, which I find to be an unthinkable choice. Holley Sniper EFI Troubleshooting Mudford Garage 8.6K subscribers 38K views 3 years ago My Bronco with Holley Sniper EFI was running poorly. If you did not rotate the distributor to set the actual timing to 15 that might be the only issue. You will find a startup IAC percentage, an amount of time it holds at that percentage, and an amount of time it takes to idle down to the normal idle speed.By default, that number is 50% at normal operating temperature. Reducing that a bit will help. Be sure to re-enable it once you get your idle tuned. The Sniper EFI system looks at the closed-loop fuel compensation required to reach your target AFR. The car cruises fine, and if I was to keep idle at 2000rpm the issue wont happen, its only when the car tries to ramp down to idle position.Thank you for your help, any advice would be appreciated.Thank you,Eric, Whenever we see the AFR go to "Heating" that is an indication that the ECU has been reset. You're going to have to get this fixed or it's going to cause even more problems than the high idle. And your question is very perceptive: You must first know whether the bog is a lean or a rich condition before you can make the correct adjustments. Turning off and then on again, the engine returns to normal. Hello, Chris, thanks for the help.I have not installed the software yet, and I'm having trouble with two cars. IAC is good 0-5% most of the time. i'm having is I can't seem to get the truck to run faster than 45 mph at speeds After 50 on the throttle position I'm not sure if the whistle goes away or you just can't here it anymore. Part# 538-13. Tuning > Advanced > Adv Idle > IAC Startup My IAC was constantly at 100% at idle. I think that the more important point is that Holley kept sending him units until everything was working. TP range is normal goes up to about 90% with throttle pedal to the floor. If not then you have some other issue that is behind this increased idle. In the setup, I set the hot idle for 850. It runs perfectly fine other wise. I have probably 200 - 300 miles on this engine and it has always done this. Cycled the ignition off. When I put it in park the idle RPM was 2100-2200 each time. I have a Holley Sniper for almost 11 month now and it was running fine with no problems until now. Are these compatible enough? Overview. For the first couple of drives it was running well, Sniper EFI was working exactly as advertised. If they are closed, check the primaries. The answer will divide the possible sources of additional air into two, greatly simplifying the problem.If the IAC number has not increased, then review the article above regarding high idle from a vacuum leak or high idle from sticking linkage. Do please let us know what you find out! I asked him a million questions and waited a long time to save up before purchasing the system and I have asked a lot of questions throughout the installation process. But if you will just advance the timing at idle and see if it makes a difference then that will tell you what you need to know. It's pretty hard to get the header tubes glowing at idle with a lean AFR. I have driven it a few times maybe 100 miles or so. Simply turn the idle speed screw on the linkage in until the throttle plates open enough for the idle to increase. Note that Brazilian gasoline has 27% ethyl alcohol. Cheers Darren. With everything else being right and since you can make it start by adding fuel it seems like you must have some sort of fuel pressure issue. If you have performed the adjustments above and still have RPM issues, it's time to look for clues. At some point you come upon problems that evade the easy answers and this is a good example. But when you have it then you can look for exactly what the IAC is doing at that point, and if there is anything that might lead to this happening. Interesting question. (If you do this you will need to reset the -40 degree setting mentioned at the top of this article. Now that you've got your IAC set I'm going to recommend that you run your setup wizard again, which will reset the ECU to the default settings. It sounds a little different from mine, since it commands a 1300 or so increase intermittently. Even at 0% it's sucking a bunch of air through the IAC port. Thanks for the information you have provided on this site. Target AFR, A / F = 13.5 The following are status commands and diagnostics for sensor and various parameters in the Holley software. If i adjust the throttle plate screw in to bring IAC in to proper range say around 7 the engine is running around 2000 rpm. To keep it running in gear, I have to bump the neutral idle up just over 1000 RPM. So this is my issue ( I did just email Holly). Since that has long been corrected we have moved that information to the bottom of the article.). I've been trying to correct that 1% small issue/annoyance. (Note: in the original version of this post we had a section about checking the idle speed curve setting. mail today. )So before I hook up another gauge to see if the Auto Meter is bad (assuming I can find a 0-100 test gauge in my shop). Fortunately, I have an article that goes into this in some detail. So the issue Im having is low idle. Why is this? Pricing was reasonable, shipping was prompt and Chris helped me with a wiring question during my install. That is likely just confusing the issue.Instead, choose whichever setup most resembles your camshaft and stick with that. you have it set. One of the most common symptoms of a Holley Sniper EFI problem is an air/fuel mixture that's too rich or too lean. But I can tell you that for most people who try this it introduces so much RFI onto the Sniper that it never works right. I was 20 minutes into a drive yesterday when all of the sudden the RPM increased not commanded. Start by doing the fastest start you can that doesn't bog. Chris---I am contemplating replacing my Holley 750 on my new low vacuum 600 HP 496 with the Holley Sniper FI system. Now it's at 5% on a big cam 440 Mopar. Both answers you've received greatly oversimplify the truth in favor of the answerer. Throttle Tip-In puts you in a part of the fuel map where you stay for only milliseconds at a time. In fact, it is those users who seem to end up most impressed with the system. Thank you for this guide on setting IAC. Thanks for any info./insight you can provide, Mark. Yes its at 95lbs, needless to say he promised a new regulator would be in the When I removed the tape and started it again, it was idling at 1400-1500 RPM and sucking a bunch of air through the IAC, even though it showed 0% on the sensors screen (pic attached). holley efi. Not that I noticed. *Possible delays due to Covid-19 click for more information. Im in Australia, so stuck the sniper on a 355 Holden engine with CD box. The Sniper ECU can use the timing to help maintain the idle speed and that will definitely be useful in that transition from Park/Neutral to Drive.If you don't have ECU-controlled timing, or if you do and it's not fully compensating, it may be necessary to increase your target idle slightly. What must remain foremost in your mind is that the only thing that can cause the idle to increase is additional air getting into the engine. I am extremely suspect of what you were told about the Sniper ECU monitoring fuel pressure, for several reasons. Hopefully replacing the pump again will resolve both issues. When you set the Static Timing to 15, what did you read with the timing light? What an amazing site you have here. This curve turns the idle speed down as the engine warms. I'm Having trouble with the Sniper on high Idle. So, this is what it takes to put a Sniper on a small-block Ford. My dad wanted to recheck the timing so I set the Static Timing at 15 and it runs perfect. Chris thank you for the info. But before you adjust the ECU to lean the idle out, first confirm that your fuel pressure is right. Thank you in advance for your help and providing us rookies with your Thank you chris for for getting back to me on this matter.I'm using russell hi pressure gas line to feed the gas up to the sniper and using the stock steel gas line that use to be the feed line for the carb to return the gas to the tank. I can get it to fire up on the This increased idle speed is triggered by grounding the orange wire in the 10-pin I/O harness. Therefore The iac will always be at 10% now, correct? It is made by one of the biggest names in fuel filters and sold under the Parts Master label so it is quality and great price in one. I appreciate everything you are saying. Give it a watch: https://youtu.be/7SO7-tZn6iw. Does this seem reasonable and how hard will it be to get the idle and off-idle performance correct? From herethe cycle continues and I am Please give this a try and let us know how it works! By the way, this is a new installation on a 69 Camaro, stock 350, dual sync, etc. Kind of cuts into forum time. They also recommended that their ground be spliced into the Sniper ground as close to the Sniper as possible. School's out for spring break this week though so I'm covering for employees on vacation. Often, folks will say, "I did everything you said. The fix? Does anyone have photos of this additional return spring they installed? Copyright 2022 Holley Performance Products, Inc. All right reserved. Mechanical Fuel Pressure Gauge on the inlet of your Sniper, now is the time. Will restart but only for a minute or so a couple of times then shuts down fuel delivery and will not restart. The fact that it ran so (at times) with 90+ PSI fuel pressure is a testimony to the Holley's closed-loop technology. Then it will ramp down to 1200 but will not return to idle. Purists will sniff that these are not accurate to the tenth of a PSI. Hello. My problem is low idle. These problems will go away when you do that. Inj. First, I'm kind of insistent about not changing any of the default settings unless the vehicle absolutely will not cooperate enough to drive/learn, and only then if you have a specific understanding of the problem and a specific solution. The broad consensus has been that the Sniper is an amazingly straight-forward install and starts and tunes as expected. I very pleased with the performance, it is a huge improvement from the 800CFM carb I had on this motor. I followed the instructions and set the IAC to 2-9% when warm with idle at 850 RPM. Cl. And so glad you guys are enjoying the Sniper EFI system. You just need to go back through the IAC adjustment procedure now that idle timing control is enabled. And thanks again for taking your time to answer these questions. Took it for a lap around the block and came back. Even at 0% it's sucking a bunch of air through the IAC port. It works instantly for him.If that fixes your problem then you have a starting place. I had HIGH Idle issue and fixing this curve FIXED the ISSUE --- THANK YOUCan you explain what "Current Learn % means, after finally fixing the idle problem this % jump from -1 to -30% in about 5 minutes at idle with CTS @ about 170.Also when starting the car at hot the engine goes to about 2300+ RPM for a few seconds then crashes down to my Hot idle speed of 950 -- bounces a little and then smooths out. And increasing your idle via the idle screw was also a good idea, because that will lower your amount of IAC that is necessary to keep your engine at the target idle speed. My Sniper started having a ticking noise-- I have 90 miles on my Sniper, but this started the last 10 miles or so: it still drives fine, but it worries me so i've stopped driving it for now. Physially manipulating the linkage by hand will generally reveal if you have a sticking linkage that is preventing the TPS from returning from zero. But after sitting static idling for a little bit, the IAC goes to 100% & stays there. I watched the butterflies start to open at about 35 on TPS. This only happens when coming to a stop and the idle is ramping down to the set idle RPM. Using a Snap-on variable timing light so this is why I say timing is perfect. I would recommend that you call first thing in the morning, as they tend to get quite busy during the day and wait times can get long. Have a look--I think this is going to allow you to fix your idle problem. The biggest issue is these problems are intermittent meaning they do not occur all the time. First, let me congratulate you on your patience in letting the system learn. In that case, and if you have an EGR valve, I might be suspicious of something going on there. Yes, having an accurate TPS is very important at idle. Thanks so much for reading! If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. When I cover it with my hands, it gets quieter. I do know that the reference angle is 57.5, the inductive delay says 100.0. But now that Terminator X is available, I highly recommend going that route. As you see above, the Sniper is going to dump in a maximum amount of fuel at zero TPS, begins to remove acceleration enrichment at 60 percent TPS, and then removes all acceleration enrichment correction at 100% TPS. Great work, expert! I know its not flooded because I can pour a little gas in the throttle body and play with the accelerator and it will start and run fine. While adjusting the screw if the TPS position reads begins to read higher than 0% cycling the ignition switch will recalibrate the TPS back to zero. If you go too low then it may stumble or even stall when coming off of throttle. One of the best Ive seen so far. Ive had an idle at neutral as high as 2400 rpm. Yes, you are correct. While it is not mandatory, I recommend the Sniper EFI CAN-to-USB Adapter to move the data between your Sniper EFI and your PC rather than trying to do this via the SD card. Fuel Prime Multiplier is primarily a benefit to throttle-body based EFI systems. What should I be looking at to calm this down? Shut off car/restart and it's back to idle at If you do find you have RFI issues then I've written an . You will need to change the -40 degree idle speed setting again but I recommend not touching anything else. If the issue persists, you may need to replace the IAC. https://www.gmperformancemotor.com/parts/19210007.html, http://forums.holley.com/showthread.3128#post83128, If this is your first visit, be sure to Commanding the engine to automatically increase speed when switching into drive is a little scary to me though. Thank you so much for your follow-up. If you use your handheld to go here: Hope this helps! 90% of problems, (INCLUDING MYSELF) could be answered/fixed by just reading the instructions. The Fuel Base map is perfect, the car works well, runs well, running through the streets, the car is great.

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