An excessively rich condition & ignition misfires will cause the WBO2 sensor to read falsely lean. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. Anyone have a good place to find a genuine Bosch O2 replacement sensor without paying $110? Sponsored Links (REGISTERED USERS DO NOT SEE THIS POST/AD! Register now for free!) Advertising. 9 fits AEM Holley Sniper Terminator X 4 product ratings Condition: New Compatibility: See compatible vehicles Quantity: 6 available 21 sold / See feedback Price: US $79. Sniper Bogging. Holley Sniper Issue solved and a tip that might help. PDF Sensor Diagnostics and Statuses. Those engines are still tough to hurt, except for detonation issues. Especially obvious when it cant idle. LED PC Text Gauge Text Description None Disabld … Signifies that sensor channel is not enabled. This allowed moisture and cold cranking fuel to contaminate (soak) heating element causing premature failure during cranking and idling. However, now that we have the Sniper back, it is time to get the car. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. WBO2 Sensor 17025 Bosch 554. Symptoms of RF Interference in Sniper ECUs The first thing to realize is that RF interference can manifest itself in ways that will have you suspecting and replacing everything in the system. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. I was just hoping for some feedback before sitting on the phone waiting for tech support. Wideband Oxygen Sensor Status Shows status of wideband oxygen sensors. Since it was reading rich, the compute. Bad Oxygen Sensor (O2) Symptoms & Replacement …. Holley Oxygen Sensor O2 Bung Weld-In Style. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. Common Check Engine Light Causes: Oxygen Sensor. Nothing is burnt through, or disconnected. Seems the Sniper should have a fail safe if it sees the rail pressure drop with an RPM (NONE) mismatch. If you notice any of the following signs, you may have a bad O2 sensor or one that is about to go bad:. Holley EFI Wbo2 Sensor, Sniper Tbi Brand: Holley 43 ratings $13295 Available at a lower price from other sellers that may not offer free Prime shipping. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. Looking down throat of the TB, with butterflies open, the intake was soaked with gas, and the small vent at rear, top of TB was showing that smokey look, like a carb would do when say you had a stuck float, and the engine was badly flooded Thats also how it was running. Yellow Cold! Cld Sensor is below calibrated operating temperature. 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. If your cars oxygen sensor is faulty, it can cause a number of problems. Tested my o2 sensors and determined the ECU on my Holley Sniper Efi is bad. When you need to service your Sniper EFI throttle body, Holleys list of parts include these O2 sensors to maintain a proper reading of oxygen levels in the exhaust. Dont know how smart they are but thats a safety feature from high pressure pump EFI day 1: no CPS RPM detected, no fuel pump relay power after 2-3 seconds. 74K subscribers Subscribe 14K views 3 years ago Attempted to make a parts run in my 1990 Third gen. O2 Sensor Mounting: The O2 needs to be mounted 6-8” after the merge in the header collector. 02 sensors are very heat sensitive, and can detect an exhaust pulsation in a single Header tube, thats why we always wanted to position the sensor into at least 2 opposite firing tubes we running Headers. 18 Part# 558-463 Add To Cart Earls. 67 Part# 558-443 Add To Cart Hooker BlackHeart Oxygen Sensor O2 Bung 2. The harnesses are long enough to mount into. O2 sensor placement is critical for getting your engine to read the oxygen in the exhaust correctly and can directly impact the performance of your new EFI installation. You may also notice reduced fuel economy, and the car may. When I go to throttle to get up on the plain a lot of the time it struggles to get full revs so I back it off and try again and then it’ll get full power. Unit will still read but accuracy may be impacted. Once you have the tune done, then close the params to 5% or so just in case you do have a wideband issue, or even a misfire due to a bad plug wire. Additionally, if an Sniper or Terminator X EFI System has repeated O2 sensor failures and none of the above-listed suggestions seem likely then contact Holley and arrange to have the unit tested. You should then have at least 18-24” of pipe after the sensor. my bad Holley bosch sensor had similar surge spot under light throttle. Holley Sniper EFI oxygen sensors are the best replacements for your system. It will lean a cylinder out and watch for the O2 to change. Bad Oxygen Sensor (O2) Symptoms & Replacement Cost. Featured Products EFI - Fuel Injection $2. Displayed so quickly you likely do not see this. I was just hoping for some feedback before sitting on. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 miles. Wideband Realities: The Truth About Oxygen Sensors. If you have any exhaust leaks between the combustion chamber and 18-24” after the sensor you are going to have problems. So, what are the symptoms of a bad O2 sensor? Here are 10 common bad oxygen sensor symptoms: Continually failed emission tests Flashing or illuminated CEL ( Check Engine Light) Misfiring, rough idling, or stalling Bad fuel economy/ gas mileage Poor engine performance Engine noises Black exhaust fumes Sulfuric/rotten-egg smell from the exhaust. Watch this short video that will give you tell tale signs to look out for if your tune suddenly runs rich or lean. From startup the AFR is sky high and visibly pumping fuel and smoke out. 8 to 12 AFR and it does fluctuate/move, I can rev the engine and hold RPM, and WBO2 reads 14 then goes back to 12. 67 Part# 558-443 Add To Cart Hooker BlackHeart Oxygen Sensor O2 Bung 2. , coil, and holley in tank fuel pump, When engine got hot it would go crazy. What O2 sensor does Holley sniper use? Not only does the AEM fit 9 Holley Sniper, but it also fits the Terminator X. In summary, below are 10 common bad oxygen sensor symptoms: Continually failed emission tests; Flashing or illuminated CEL (Check Engine Light) Misfiring, rough idling, or stalling; Bad fuel economy/gas mileage; Poor engine performance; Engine noises; Black exhaust fumes; Sulfuric/rotten-egg smell from the exhaust; Sudden catalytic converter. I also noticed the Sniper trying to run more lean in these moments than normal (like 15. Your mechanics labor costs also likely vary based on a few factors, including how difficult it is to access your sensors. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. Replacement Sniper and Terminator X O2 Sensor. O2 sensor placement is critical for getting your engine to read the oxygen in the exhaust correctly and can directly impact the performance of your new EFI installation. Symptoms of RF Interference in Sniper ECUs. locating an O2 sensor in a side pipe. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. Explained: Holley EFI Sensors and What They Do. Top 10 Sniper EFI Installation Tips from Holleys Tom …. 6 afrs when it cutted out and compensation added tons of fuel to it and made engine sputter and stall. #4 · Oct 13, 2022 My O2 sensor issues were determined to be the sensor tip being to deep into the exhaust pipe. Any ideas on where I should go next if the O2 sensor doesnt help? Coolant sensor? Of do I have to start posting my data logs on the Holley Forum??. - Fuel pressure has been verified at the Sniper EFI throttle body and is between 55 & 65 psi - All wiring has been tied away from potential hazards such as the exhaust, fans, pulleys, spark plug wires, 12 Volt accessory wires, the ignition coil and ignition coil wiring. Discussion Starter · #7 · Jun 3, 2016. So, its important to keep an eye out for symptoms of a bad oxygen sensor and fix it as soon as possible. On EFI systems such as Holleys Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. The best way to describe the symptoms is that at light throttle (<10% TPS) theres a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. Your car may run sluggish and rough, with. got worse pretty quick sensor showed 35. Sniper EFI Installation Tips from Holleys Tom Kise>Top 10 Sniper EFI Installation Tips from Holleys Tom Kise. It is possible for the ECU to have an internal failure that can kill O2 sensors. Holley Sniper Bad ECU FINALLY FIXED!. About this item Genuine Holley Quality Parts Corrosion resistant Made from quality materials Easy installation Durable and long lasting › See more product details Frequently bought together +. Yellow Heating HO Sensor is heating. I also noticed the Sniper trying. I reinstalled sensor turned Closed Loop & Learn off and restarted truck. if it suddenly goes leanyou know the sensor is bad if after a minute its still pegged rich, the sensor is good This test works with ANY o2 sensor Click to expand Back in the 20th century , I used a DMM that read frequency and looked for 5Hz or over for a good sensor in closed loop with the sensor good and warm at a fast idle. 74K subscribers Subscribe 14K views 3 years ago Attempted to make a parts run in my 1990 Third gen Chevy Camaro with a small block chevy. Since I replaced the O2 about a year ago I figured what the hell, lets try to clean it. One of the reasons is that OEM EFI systems are constantly testing the engine. When you need to service your Sniper EFI throttle body, Holleys list of parts include these O2 sensors to maintain a proper reading of oxygen levels in the exhaust. If you leave a bad oxygen sensor in your car for several months, it may cause serious damage to the engine and catalytic converter. 95 Part# 554-101 Add To Cart Holley EFI Oxygen Sensor. It’s seems to be doing it quite often. Holley Sniper O2 sensor replacement. The Holley sensor took a few minutes to start working again, because of all the soot, but it came back to life. Holley Sniper O2 sensor replacement. Holley Sniper EFI troubleshooting: Bad ECU??. Additionally, if an Sniper or Terminator X EFI System has repeated O2 sensor failures and none of the above-listed suggestions seem likely then contact Holley and arrange to have the unit tested. I also noticed the Sniper trying to run more lean in these moments than normal (like 15. The owner is frustrated because the engine is running way. Holley EFI; Sniper EFI; If this is your first visit, ension-Harness (WBO2 Sensor Test At End Of Wideband O2 Sensor Notes) May Gods grace bless you in the Lord Jesus Christ. Sniper EFI Coolant Temperature Sensor: $26. Yellow Heating HO Sensor is heating. 02 sensors are very heat sensitive, and can detect an exhaust pulsation in a single Header tube, thats why we always wanted to position the sensor into at least 2 opposite firing tubes we running Headers. Subscribe 13K views 3 years ago Tested my o2 sensors and determined the ECU on my Holley Sniper Efi is bad. Holley EFI Oxygen Sensor. This video could save you hours of time on the dyno. A N/A engine is a lot harder to hurt than a power-adder engine, except for high-rpm and high-compression stuff. Long story short, I managed to delete the current file and replace it with the current FW: tslcd35st_sniper_fw_01_03_0500. Ive gone through a bunch of the Holley 02 sensors and at $240. Symptoms of a Bad or Failing Oxygen Sensor. Additionally, if an Sniper or Terminator X EFI System has repeated O2 sensor failures and none of the above-listed suggestions seem likely then contact Holley and arrange to have the unit tested. I have a feeling there is an issue inside the unit. Sniper EFI Releases new Stealth 4150 Models! Staff. On EFI systems such as Holleys Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. RPM going up and down , miss firing and. my bad Holley bosch sensor had similar surge spot under light throttle. worked fine while idling and driving harder. Common Check Engine Light Causes: Oxygen Sensor. We double checked all wiring, no exhaust leaks, etc. My firm guess is that they dont and will find be a much cheaper alternative. Once you have the tune done, then close the params to 5% or so just in case you do have a wideband issue, or even a misfire due to a bad plug wire. The Sniper EFI unit only requires four wiring connections: battery positive and negative; a key-on, 12-volt source; a crank signal; and an rpm signal. Free Shipping - Lower 48 US States. Yellow Cold! Cld Sensor is below calibrated operating temperature. You may also observe other engine performance problems, such as loss of power, hesitation, or stalling. 95 Part# 554-100 Add To Cart Holley EFI LSU4 Bosch Wideband $194. I know from some of the other posts, there have been WBO2 sensor issues. These replacement Bosch wideband sensors feature anti-seize pre-applied to sensor threads. I bought a new holley sniper , dual sync dist. The best way to describe the symptoms is that at light throttle (<10% TPS) there’s a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. In summary, below are 10 common bad oxygen sensor symptoms: Continually failed emission tests; Flashing or illuminated CEL (Check Engine Light) Misfiring, rough. Replacement Sniper and Terminator X O2 Sensor. Share 02-13-2006, 10:36 AM #8 adham Member. Installed a Lokar throttle linkage bracket custom made for the Sniper, removing the old one that had been on my Holley 750. I ended up disconnecting the WBO2 sensor to get it to run and back home. If you have any exhaust leaks between the combustion chamber and 18-24” after the sensor you are going to have problems. Obviously, if the O2 sensor did not respond properly then it is bad and will need to be replaced. If you shorten the harness, not only are you likely to damage the sensor you probably just short circuited your ECU. The first thing you should do when you suspect that you have RF interference is. Have you tried manually tuning the idle in Open Loop? (Disable Closed Loop in System Parameters. I removed WBO2 sensor from pipe and let dangle in fresh air. This ensures that the O2 sensor takes its measurements after the exhaust gas from each primary merges into a common collector. Sniper EFI Coolant Temperature Sensor: $26. Check Engine Light Illuminates. 2 block, forged steel crankshaft & H-beam rods, forged pistons, Trick Flow Twisted Wedge 11R 205 CNC. 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. Many sensors, nonetheless, cost between $20 and $100. Holley Sniper Issue solved and a tip that might help>Holley Sniper Issue solved and a tip that might help. Holley EFI Oxygen Sensor. Yellow Init… In First shown for an instant when the system is powered on. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. It needs the tip pointed down at least 10 degrees from horizontal and at least 15 degrees from vertical I prefer. In one of the other posts someone said they used the Bosch 17025 LSU4. Holley Performance >Changed mufflers, now 35. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. It must be actively driven and controlled by the ECU. It needs the tip pointed down at least 10 degrees from horizontal and at least 15 degrees from vertical I prefer about a 45 degree angle from horizontal. This fixed the high throttle position sensor reading (TPS) of above 1% that likely caused my idle issues. The O2 sensor is not a passive sensor that simply sends back data. I happen to have a box of them here, as I use them on the dyno for tuning. Im sure the front O2s are completely clogged possibly giving me a rich condition. bad o2 sensors=power loss?. Also the closer the O2 to the engine, the quicker the O2 heats up to give a reading on a cold start. Fine tuned the timing to 12-15 degrees. As your oxygen sensor is going bad you may notice your vehicle is running rough, misfiring or running irregularly while idling. 9K subscribers Subscribe 25 Share 2. How To Check Your O2 Sensor At Home. Not much changed it, restarting, idle, full throttle. Looking down throat of the TB, with butterflies open, the intake was soaked with gas, and the small vent at rear, top of TB was showing that smokey look, like a carb would do when say you had a stuck float, and the engine was badly flooded Thats also how it was running. Subscribe 13K views 3 years ago Tested my o2 sensors and determined the ECU on my Holley Sniper Efi is bad. Holley part number 554-155. The potential issues could be a vacuum leak, ignition system, or something similar. 99 Add to cart Add to Watchlist 1-year accident protection plan from Allstate - $10. 22 Part# 543-120 Add To Cart Holley EFI CAN to USB Dongle - Communication Cable $65. The best way to describe the symptoms is that at light throttle (<10% TPS) there’s a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 miles. Your car may run sluggish and rough, with stalls, and poor fuel efficiency. Here is a more detailed list of the bad oxygen sensor symptoms: 1. Bosch 17212 Wideband Oxygen O2 Sensor LSU4. An excessively rich condition & ignition misfires will cause the WBO2 sensor to read falsely lean. #4 · Oct 13, 2022 My O2 sensor issues were determined to be the sensor tip being to deep into the exhaust pipe. You may also notice reduced fuel economy, and the car may fail an emissions inspection. Holley Sniper Bad O2 Sensor SymptomsSeems the Sniper should have a fail safe if it sees the rail pressure drop with an RPM (NONE) mismatch. I removed WBO2 sensor from pipe and let dangle in fresh air. 15 Part# 71014302-RHKR Add To Cart Holley EFI Terminator X Wideband Adapter Harness $47. The Holley sensor took a few minutes to start working again, because of all the soot, but it came back to life. 10 Bad O2 Sensor Symptoms (What to Look Out For). No Start Condition Engine Runs Poorly at Operating Temp Erratic Idle Condition Incorrect Fuel Pressure Magnetic Distributor Timing Control Setting Crank Reference Angle to 45°. The best way to describe the symptoms is that at light throttle (<10% TPS) there’s a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. On the contrary, even a failing O2 sensor (sometimes called a “lazy” O2 sensor) may cause. The distance to the O2 sensor impacts the response time. The ECU controls the fuel mixture, idle speed, ignition timing, and in some cases, valve timing, and drive-by-wire throttle-body if so equipped. my bad Holley bosch sensor had similar surge spot under light throttle. If your cars oxygen sensor is faulty, it can cause a number of problems. Watch this short video that will give you tell tale signs to look out for if your tune suddenly runs rich or lean. I ended up disconnecting the WBO2 sensor to get it to run and back home. If ignition is turned on and the engine is not started, after a period of time, the AFR will start reading “Init…” until the Sniper EFI ECU sees an RPM signal. If you notice any of the following signs, you may have a bad O2 sensor or one that is about to go bad: An illuminated check-engine light A rough engine idle A misfiring engine Worsening fuel economy Failed emissions inspection. 4K views 9 months ago This is my 1959 Ford F100 that I’ve had. If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. Solving RF Interference Issues in Sniper Installations. Once you have the tune done, then close the params to 5% or so just in case you do have a wideband issue, or even a misfire due to a bad plug wire. If your cars oxygen sensor is faulty, it can cause a number of problems. So I spraying it down with carb cleaner trying to shoot it in the slits. 22 Part# 543-120 Add To Cart Holley EFI CAN to USB Dongle - Communication Cable $65. To Properly Place and Install an O2 Sensor. 4K views 9 months ago This is my 1959 Ford F100 that. 00 a pop Im going to figure out if they need to cost what they do from Holley. 95 2129 Products View Parts Sensors. Sensor Diagnostics and Statuses. Featured Products Holley EFI NTK Wideband Oxygen Sensor $318. Troubleshooting Holley Sniper that hesitates on acceleration. Using a timing light for misfire detection works well (watch for a consistently flashing strobe light). This price, of course, varies from vehicle to vehicle. Holley efi behavior with bad o2 sensor, safety feature>Holley efi behavior with bad o2 sensor, safety feature. 5 AFR instead of high 13s or low 14s). This minimizes installation time and packages really well on a diverse group of engine applications. One of the reasons is that OEM EFI systems are constantly testing the engine. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. The owner is frustrated because the engine is running way too rich, fouling plugs, and generally runs poorly. worked fine while idling and driving harder. On the contrary, even a failing O2 sensor (sometimes called a “lazy” O2 sensor) may cause your car to have a few issues. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 miles. - Fuel pressure has been verified at the Sniper EFI throttle body and is between 55 & 65 psi - All wiring has been tied away from potential hazards such as the exhaust, fans, pulleys, spark plug wires, 12 Volt accessory wires, the ignition coil and ignition coil wiring. Add to Wish List Service Oxygen Sensor for Sniper EFI Systems;. On EFI systems such as Holleys Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. An oxygen sensor does not have to fail completely to give you problems. The nature of the hesitation feels more like gas than spark. Symptoms Of A Bad Oxygen Sensor And Replacement Cost>8 Symptoms Of A Bad Oxygen Sensor And Replacement Cost. Started truck and WBO2 sensor showed 23 AFR. An oxygen sensor does not have to fail completely to give you problems. If the O2 sensor fails to respond correctly to the lean and rich fuel tests, another component could be causing the problem. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000. Holley sniper failure, this time its all bad. Here is a more detailed list of the bad oxygen sensor symptoms: 1. It uses the sensors to monitor specific engine parameters and make changes to those based on the information it is receiving about the engine’s operating conditions. car is a third gen 1990 Chevy Camaro with flowmaster mufflers. Pay specific attention to the O2 sensor cable lead. Sniper EFI Coolant Temperature Sensor: $26. This ensures that the O2 sensor takes its measurements after the exhaust gas from each primary merges into a common collector. These replacement Bosch wideband sensors feature anti-seize pre-applied to sensor. 1 Syleng1 Karma is real and Life is short FABO Gold Member Joined Jul 5, 2005 Messages. An excessively rich condition & ignition misfires will cause the WBO2 sensor to read falsely lean. Fine tuned the timing to 12-15 degrees. It has been a month and the light hasnt come back on. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 >Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000. Positioning the sensor too close to the exhaust ports can expose it to high exhaust gas temperature (EGT) as well as over-cooling from the high-velocity exhaust gas flowing over the sensor. On the contrary, even a failing O2 sensor (sometimes called a “lazy” O2 sensor) may cause your car to have a few issues. It can also lead to high pollution levels. This ensures that the O2 sensor takes its measurements after the exhaust gas from each primary merges into a common collector. When it’s up & going it runs smooth but just getting there is a hassle. Its sort of like vapor lock, but I drove this car for three years in Texas summers with no issues. The most typical culprits are the spark plug and coil wires. O2 Sensor Mounting: The O2 needs to be mounted 6-8” after the merge in the header collector. Holley Oxygen Sensor O2 Bung Weld-In Style. Knowing what all the moving parts inside and. Yellow Hot! Hot Sensor is above calibrated operating temperature. Anyone have a good place to find a genuine Bosch O2 replacement sensor without paying $110?. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. From startup the AFR is sky high and visibly pumping fuel and smoke out. Holley Sniper EFI oxygen sensors are the best replacements for your system. If ignition is turned on and the engine is not started, after a period of time, the AFR will start reading “Init…” until the Sniper EFI ECU sees an RPM signal. Red Unplugd UnP Sensor is unplugged. It can also lead to high pollution. This car runs on methanol, and at the track the last couple outtings the car was misbehaving and reading really rich. Holley Sniper EFI Oxygen Sensors 554. It is possible for the ECU to have an internal failure that can kill O2 sensors. Bad Oxygen Sensor? Holley NTK. Discussion Starter · #7 · Jun 3, 2016. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. All engine compartments have a bounty of sources for RF noise. Holley EFI Wbo2 Sensor, Sniper Tbi Brand: Holley 43 ratings $13295 Available at a lower price from other sellers that may not offer free Prime shipping. Last summer, a faulty ECU in my Holley Sniper EFI took out my 1972 Ford Mustang, bringing it into early storage for winter. Long story short, I managed to delete the current file and replace it with the current FW: tslcd35st_sniper_fw_01_03_0500. Wideband Realities: The Truth About Oxygen Sensors …. Pinched or Burnt O2 sensor Wiring: Keep it high, tight, and safe. Typically, labor costs for a sensor replacement are around $150. The nature of the hesitation feels more like gas than spark. Holley Sniper that hesitates on acceleration>Troubleshooting Holley Sniper that hesitates on acceleration. This one came in with black clouds and 100% fuel Learn on the handheld barely running, with the WBO2 reading at 35:1 AFR. Symptoms of RF Interference in Sniper ECUs The first thing to realize is that RF interference can manifest itself in ways that will have you suspecting and replacing everything in the system. Positioning the sensor too close to the exhaust ports can expose it to high exhaust gas temperature (EGT) as well as over-cooling from the high-velocity exhaust gas flowing over the sensor. Also, with Headers you loose 600 to 700 degrees between Head and bottom collector, you dont want to read that loss. Sponsored Links 09-27-2020, 10:39 PM. suspect bad o2 sensor with Holley efi. Crankshaft position sensors allow the ECU to interpret how fast the engine is spinning and where it is at in its rotation. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. Since I replaced the O2 about a year ago I figured what the hell, lets try to clean it. Yellow Heating HO Sensor is heating. O2 Sensor Mounting: The O2 needs to be mounted 6-8” after the merge in the header collector.