Some wires simply won't work in an EFI-controlled vehicle. I offer this troubleshooting guide to give you some of the symptoms of RF interference, common targets and sources, and then tips for solving it. Carbureted engines can suffer problems as well. HP ECU's. check out the. Holley Sniper O2 sensor replacement - Club Cobra #2 Wire It Properly Most important!!! This is also why stock GM LS camshafts use an LSA between 116 and 122 degrees to smooth the idle and help the O2 sensor. In this case, a big cam in the engine was fooling the O2 sensor and the tuner thought the engine was too lean! Is this the coil failing or could it be a sign of a downstream issue (with the plug gaps maybe) thats backing up too much resistance in the coil? I better heed their warning, since I have had no less than five returns on defective Holley parts so far, and I don't want to jeopardize the warranty. O2 sensor failure on a Holley Sniper EFI - YouTube If your mixture is too rich, it means there's too much fuel and not enough air. This may not sound like a big deal, but it changes the fuels stoichiometric number from 14.7:1 to 14.1:1. That arcing will result in EMI. The first thing you should do when you suspect that you have RF interference is to double-down on all of the best practices that are given in the installation manual regarding wiring. Thanks for commenting! Crank the engine and peak under the hood. This can be caused by a problem with the spark plugs, wires, or coil. Increased gaps increase spark resistance, causing energy to be emitted from the plug wires. This is a display of EMSs 5-gas analyzer on that big-block El Camino. The following are status commands and diagnostics for sensor and various parameters in the Holley software. If your idle speed is constantly fluctuating or seems higher than usual, it's another sign that something's wrong with your Holley Sniper EFI system. Lets look at why this occurs. These sensors (which includes the coolant temperature and MAP sensors) receive a 5-volt source and ground. We offer a spare wire removal kit for just this purpose. MSD 6AL. The engine was equipped with a relatively mild hydraulic roller camshaft that did have some overlap. I found my problem. Any advice? The CO2 is 12.4-percent, CO is 3.42-percent, HC is 481 ppm, O2is 0.3-percent, NO2 (NOx) is 105 ppm and the AFR is 13.14:1. RF Interference is an unavoidable enemy to successful EFI operation so it must be carefully and thoughtfully managed. Now, read on to get a deeper understanding of the problem. You're proof that it can be done. This Crimping Tool is available with the Delphi 12048074 Metri Pack 150 Series Female Terminals that you'll need to reterminate after you shorten the wires. Jun 24, 2015 I had a Holley bosch sensor bad from jump . Replaced and gapped to .45 all spark plugs. For this example, well look at overlap on two Comp small-block Chevy hydraulic roller cams. This page was generated at 03:38 PM. That's because the ECU was seeing the same thing and flooding the engine because of the false RPM readings. (77 46 = 31 degrees difference in overlap between Cam A and Cam B). For example, on our shop truck our spark plug wires go immediately down and straight under the manifold to the spark plugs. If you're going to try this, start by wrapping the harnesses wherever they are exposed. In a non-ECU controlled ignition setup, such phasing is done automatically. Ask questions or send a hint for future articles on the author's page. We commanded a 13.2:1 AFR and the HC count dropped, revealing that the engine wanted the extra fuel to idle more efficiently. Note: Do not attenpt to shorten (or lengthen, for that matter) an O2 sensor's pigtail. First of all. Great job, Dewayne. Problem gone. Start by removing and cleaning every single power and ground connection between the alternator and battery. To diagnose a problem, start by ruling out the simplest causes first. As overlap increases, that little triangle becomes larger, which will allow more free oxygen into the exhaust and fool the O2 sensor at idle. After some research I replaced the o2 sensor. I know they'll find the problem. Once that ratio is calculated, the meter displays that information as an air-fuel ratio (AFR). *Free Shipping & Handling only offered to the contiguous US on orders over $100, excludes clearance parts and oversized packages. If you think your throttle position sensor is failing, working some of the time and other times it is registering negative percent, my first suspicion: RF Interference. Holley puts a resistor in the sensor harness under the shrink wrap . If any wires are frayed or broken, replace them with new ones. Not only will they have the necessary tools and expertise to troubleshoot the problem, but they'll also be able to identify any other potential issues with your vehicle that could be causing the problem. And I just tracked my EFI (Holley didn't pay for any expedited shipping) it will be a full week (7 full days) before it gets to KY. Holley Sniper EFI is a popular choice for carbureted engines, but it's not without its issues. 04-24-2022, 10:39 AM I had a few issues with the Holley Sniper System. Hope this helped someone in the future Even if it does show good continuity pull not only the alternator but the bracket as well. Reflected RFI situations like this one requires more in-depth investigation. Assuming your ohm meter zeros when you touch the leads together, if it is even one ohm that is more than it should be. Bosch part number 17025 it's the same as the holley part and I found it on ebay for 35$ shipped the holley and local parts stores wanted 140$ I bought 2 Car runs fine again. I"m going to gap down to 0.35 to 0.45. Many, many years ago I discovered the "lightning storm" mentioned in the article. One zone where there is nothing but ignition wires and another zone for power and signal wires. According to the manufacturer, the most common problems are fuel starvation, electrical interference, and backfires. They key is to be persistent and solve the problem, preferably by identifying and removing the source of RFI. Don't get crazy--if you set this too high then you will have troubles cranking the engine. Many times I called Holley and ask why it wouldn't tune itself. However, in the event that RFI has reared it's ugly head in your installation, these tips should put you on the right track. Recently I received a data log from a customer who said that his car starting misbehaving when it got warm. But you aren't the only one seeing that. That is understandable, because there may be absolutely no other indication. Once arcing occurs, carbon traces form on the outside of the plug and that provides an even better conduit for ignition energy. So, failing that, replacing the coil is a good way to test this theory. When the engine is started again, the whole process repeats. What solutions worked best for you? At low levels RF interference will often reset the ECU so quickly that the engine will not stall. This is the seventh unit I've installed and know there have been some bad sensors right off the bat with these. After going round and round I found that the RPM readout on the handheld display goes crazy reading anywhere from 200-7000 RPM while the engine is just trying to idle. Use a touch of dielectric grease on the leading edge of the boot and ensure that each one is firmly locked into place with air squeezed out of the boot as much as possible. If you swap the TPS and have the same problem then you probably do have an RFI problem. Very rare but when that happens you need to stop feeding it O2 sensors at maybe number 3 or 4 (not number 7) and send the unit back to be checked. Tech Resources. Aug 17, 2013 I had an o2 sensor fail on a pass yesterday, and flatline at 11.5afr. Turns out he did. Start by using an ohm meter and check the resistance between the alternator case and the block. In the installation manual you will find a "General Wiring Reference" with two paragraphs of "Do's" and "Donts". The HyperSpark unit you picked up is going to be a world better. Sponsored Links (REGISTERED USERS DO NOT SEE THIS POST/AD! Unfortunately, I cannot offer you an easy litmus test that shows if the coil is breaking down. Same every time. Holley Sniper O2 sensor replacement Holley part number 554-155. This test revealed that the AFR moved to 13.2:1 and power was down from the baseline but only slightly. Sniper loses signals while driving. - Holley Performance Products Forums Last ditch effort, i sent the entire unit back to Holley for testing. Here is what I have done so far: - Sent data log to Holley. I have seen cases where the ECU gains an appetite for eating O2 sensors. Not a bad idea and definitely worth a try but so much of this is trial and error. Anyone have a good place to find a genuine Bosch O2 replacement sensor without paying $110? Yeah, it's best to do it right, and you won't have any more early WBO2 failures with the Innovate Motorsports. Third, check the fuel filter. One is to get the vehicle somewhere it is as close to pitch dark as possible. I had a little trouble getting a signal to my MSD box to fire the coil during cranking. I mentioned to the customer that he could be getting EMI from his alternator and he thought, "I know a quick way to check that--disconnect the alternator!" Increased gaps increase spark resistance, causing energy to be emitted from the plug wires. I have a Sniper EFI unit here that we installed for a customer and it has come back for WBO2 sensor issues. A plug wire that runs too near the Sniper or plug wires that run near any of the sensor wires are often the root cause. Thanks Chris for the feed back regarding my rough running sniper/timing issue even though I bought my sniper through Holley. What's the AFR value? If that doesn't work its probably time to replace that alternator. The coil is similarly mounted to put the coil wire in this zone. Shielding is really taking the wrong approach. That's generally a good thing. A 350ci small-block Chevy with this cam idled at 14 InHg of manifold vacuum at 850 rpm. If you're like many car enthusiasts, you may be considering a Holley Sniper EFI system for your next project. Even a small exhaust leak will pull fresh air in from the outside and greatly exacerbate this free oxygen problem. RPM going up and down , miss firing and backfiring. Terminator X Max 700R4 LS2 L92 heads and LS3 525hp cam and Jim Inglese 8 stack fuel injection. This will make the O2sensor readings far more accurate. Our version is that with that particular O2sensor that might be a correct statement. We took a known good alternator and bolted it onto the Pontiac but the issues unchanged. Would having a hole drilled in my Cap for phasing be bad for emi/rfi ? And, surprisingly, not just any wire that says "eliminates radio frequency interference" actually does. Rather, it is acting as a reflector, and grounding it doesn't seem to have much impact on that. And finding the problem often is easier than you might think. One solution to this issue is to make sure there are no leaks in the system that could contribute to this problem. What we know is that the indicated 12.4:1 is too rich. If youre not sure if your O2 sensor is accurate with a big-cam engine, you can always pull a spark plug and look at it. The msd I was using was I dont know how old. An ungrounded plate tends to reflect it-- sometimes right down into the ECU. This bung location needs to be verified before using it with the Oxygen sensor included in the Sniper EFI system. The point is that not all gasoline has a stoich of 14.7:1. Since nearly all wideband oxygen sensors uses 14.7:1 as the baseline from which to calculate the actual air-fuel ratio, right from the beginning the O2sensors display is off by roughly half a ratio. Ideally the bung will be 6-10 inches after the collector for a true reading of all cylinders and have a minimum of 18" length past the sensor location. First, check the fuel pressure. Backfires usually happen when the timing is off or the air/fuel mixture is too rich. If you ever have any questions or concerns, don't hesitate to contact a Holley Sniper EFI certified professional. That will also create arcing. A 383ci small-block Chevy with this cam idled at 9.5 InHg of manifold vacuum at 950 rpm. Engine builders and tuners all agree that when evaluating a tuning routine its always recommended to adjust air-fuel ratio and timing for what the engine wants, not necessarily toward a specific number. Because O2sensors use free oxygen as their only measurement for calculating AFR, they can be subject to significant error when working at idle on engines equipped with long duration camshafts and/or cams with excessive overlap. The next step is to start over by re-booting the system, establish a decent running AFR where the engine runs cleanly at idle (regardless of what the O2sensor reads) and then disable the learning function at idle so further corrections do not continually add fuel to the system. This is where I will get all of my EFI equipment from now on.The MSV and filtering settings make a HUGE difference. Just remember to use that wideband gauge as a comparator. Don't hesitate to call, nights and weekends included.) multi-port EFI systems But since the factory can't know how long wires you might need they tend to make them too long. This only occurred at idle. Being a sharp tuner means understanding how all the systems work and then using that information to make intelligent decisions. Once potential causes have been ruled out, more targeted tests can be performed using a digital multimeter or a handheld tuner. Just for fun, we calculated the overlap numbers for the largest Comp Mutha Thumpr cam which came to 88 degrees! - Replaced all plugs, Ohm tested all plug wires. Any ideas? If there is air in the lines, bleed the system to get rid of it. VPs Q16 racing gasoline is a highly oxygenated example of a fuel that is a long way from a stoichiometric AFR of 14.7. $52.52. These wires should be removed at the connector and replaced with a sealing cavity plug. But denying the problem won't get it solved. Unfortunately, it is not currently possible to change the MSV from the handheld. Troubleshooting Holley Sniper that hesitates on acceleration Stretch, What I Learned Today With Jeff Smith Homemade Strap Wrench, Build It Yourself Builds Worlds First 8,000 RPM 4-Valve Triton V10, Everything You Need To Know About The 2024 L5P Duramax Engine. But right away its important to mention that nearly all pump gasoline sold in this country is laced with 10-percent ethanol. Then when the engine is shut off, most of the self-learning systems add this fuel to the long-term fuel trim number richening the overall fuel delivered at idle. The throttle body itself is generally fairly well grounded when bolted into place so, by extension, so are the air cleaner plates. This is where a preconceived notion that the engine should run at 13.8:1 would not necessarily be what was best for the engine. But there have been such gains in technology on these CD boxes over the last few years that anyone with a box more than about 10 years old really needs to consider replacing it before it leaves them stranded. Same. Also pay attention to the contact surfaces of the rotor and the cap. Many thanks in advance for any assistance. But if you're fighting RFI then it's time to step up and do this. For example, if the engine is running lean, it could be due to a dirty air filter or a restricted fuel line. This isnt as dramatic as it sounds, since a majority of learning with these systems is accomplished within the first hour of driving the engine in various situations. Try a completely different style of alternator. Cold starts good, hot starts good and runs good in open loop. If it were then grounding it would solve the problem. The "PC Text" indicates what will be shown on the PC/Laptop data monitor or data logger. By following these simple steps, you should be able to fix most electrical interference problems with Holley Sniper EFI. Come join the discussion about performance, builds, restoration, modifications, classifieds, troubleshooting, reviews, and more! Very good read! I tried Holley but didn't get much, so I thought I'd try Chris but knowing he owed me nothing.Well let me say he responded to my questions and concerns quickly, read some of my datalogs and provided some great advice. Most import. Fine tuned the timing to 12-15 degrees. PDF -849 Shiny, 550-850 Black, & 550-851 Gold) -852 Shiny, 550-853 - Holley In this first picture you see a quick blip of the throttle (light green trace) and the resulting increase in RPM. They sent me a new WBO2 and when that didn't fix my flashing red pegged AFR, they had me return the whole unit. I'm glad you enjoyed the article. Sand to bare, clean metal every mating surface between the alternator and the engine block. A high HC number could mean that the AFR is excessively rich. Another symptom is the engine is backfiring or stalling. However, if you have done everything else then this is absolutely worth a try. Troubleshooting Holley Sniper that hesitates on acceleration It never hurts to try but we've seen very limited success from grounding the air cleaner base plate. The oxygen sensor is a critical component of any electronic engine management system, and relays real-time air fuel mixture data to the computer for minute adjustments to fuel mixture. This is a photo of the screen as the car was running 65 mph on the highway in overdrive. Well my HBX-1 is sitting at 1 o'clock vs straight ahead, I wonder how critical it is to be straight at 12 o'clock? Doubt it? He directed me to a few articles and I'm just about done with the set-up after getting what was most likely RF Interference issues sorted out. This can cause the engine to run rough and may even lead to engine damage. Fortunately, these problems can often be fixed with a simple adjustment to the air/fuel mixture. When it comes to diagnosing a problem with a Holley Sniper EFI system, timing is everything. Below are the answers to the Setup Wizard: We use the "Street Strip" cam profile Enter your CID Enter desired idle RPM (750-950 usually) Use the "coil negative - no timing control" timing setup To install the Sniper-equipped engine into your vehicle, take note of the following wiring parameters: There is very little free oxygen at 2,000 rpm and the calculated AFR reveals that it might be running slightly rich. I would absolutely recommend replacing that. That's why I am not a big fan of increasing spark gap.But the in-coil arcing you are experiencing doesn't sound right to me either. Close 21 ATDC = 46 degrees of overlap. These wires are necessary so they can't be removed like the spare wires mentioned above. We promise not to use your email address for anything but exclusive updates from the Power Automedia Network. Well, it's on it way back to Holley. The old school way of tuning carburetors with a tach and a vacuum gauge may be crude, but will also get you close especially on engines with big cams. When we say, "They just don't make them like they used to", we generally mean something is not as good as it used to be. $1000 dollars wasted & unreliable. If you don't have "Magnetic" selected as you rignition type then none of this applies to you. "Hey, you don't happen to have an electric fan coming on at about 185 degrees, do you?" #1 35+ AFR, replaced WBO2 sensor, same problem. I hope they have them dialed in better for future users? This fan is an atypical source of RFI. But if you have any problem (particularly with a rich running condition) you can know that you know that it's not spark plugs when you can just swap in a fresh set. "But you don't understand, My spark plug wires are brand XYZ, the best on the planet, and for that matter they are brand new!" Instead of fixing the problem, we leave the problem in place and go on the defense, trying to cover up wires, ECUs, and sensors that might be affected by RF energy. With the advent of EFI systems like the Sniper EFI System more and more of the details formerly left to the installer are being completed at the factory to provide a "plug and play" experience. I 'am just terrible with electronics. I finally found this piece that Chris produced, read it, thoroughly went back and took the time and trouble to check on all new equipment--plugs, wires, boots, wire routing and all. Holley Sniper EFI suddenly severely overfueling - Team Chevelle Ensure the Crank Signal Positive / Negative wires (Purple and Green) are twisted snugly together the entire length of their run. But i did notice they are non restistor style ngk b6es. May God's grace bless you in the Lord Jesus Christ. On EFI systems such as Holley's Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body . So if you recognize that then you are probably okay in that area. Admittedly, the HC difference was minor, but the point is that when we richened the idle AFR, idle vacuum also increased about 0.5 InHg. Several tries and "fixes" later i found that if the alternator in unhooked the problem immediately goes away. So he did. Installed a Lokar throttle linkage bracket custom made for the Sniper, removing the old one that had been on my Holley 750. Normally this means you have too much gap. When it comes to troubleshooting a Holley Sniper EFI system, there are four main symptom areas to watch for: fuel delivery, ignition, air/fuel mixture, and timing.
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