I just finished putting a set of Flowtech afterburner headers on, and at that time changed the plugs. OUT! 1. Other than a lean misfire nothing pops back through the carb on hard acceleration like a wiped out cam lobe on the exhaust side. sounds like its running on bad gas , so i'd check the timing as was mentioned. 5” opening, and the billet tip is straight. Share. 5 turns out. No need to go higher unless you're running a custom tune for 91/93 or higher. Could this loss of power be due to expansion upon detonation in the Sep 15, 2008 · Summarily, if your car has similar symptoms (hesitation, sluggish acceleration, rough idle, and power loss) as I’ve reported above, it’s worth a shot trying the PEA-containing fuel system cleaners ($16 for 2 bottles of 12 oz. backfires on deceleration. Slowly lowering the RPMs will often avoid the backfire. Rich Air/Fuel Mixture: One possible cause is a rich air/fuel mixture, where there is an excess of fuel compared to the amount of air in the combustion chamber. 06 BF 750 (Silver) SOLD. Low-quality fuel often contains impurities that can clog up your motorcycle's fuel system, including the carburetor Apr 8, 2010 · 302 rough idle, hesitation, backfire through carb. 11-06-2022, 09:53 AM. The loud, violent sound that you hear results from late ignition in the combustion process. As of today it starts fine and idle's fine but when accelerating you can get up to speed by slightly pushing the pedal,but if you try to give it some gas anything above slightly pressing the pedal it hesitates and backfire once you push it to that point then it hesitates at Sep 27, 2022 · PlaywithTBI. Only mods to the 4160 carb was the 4. Apr 17, 2013 · Snake556. It has good spark compression at 64 psi and it 351w, Holley, Backfire through carb on hard acceleration? So I have a 1983-ish 351w, bone stock, purchased as a . like above about 20K rpm, the engine will start jumping up 10k rpm's, then back down, then back. Probably has 5,000 miles on it. /228 exh. May 18, 2019 · Step 1: Identify the Cause. Dec 4, 2021 · Getting around 6 MPG. Since then I have replaced all hoses to Oct 10, 2019 · First off, you need to determine whether it is backfiring out the exhaust or back up through the carb. Not a backfire. Under hard acceleration I get a popping kind of like a backfire. However, every time I go WOT or even Apr 29, 2019 · OK, so having a bear trying to get the SBC running smooth. It usually starts around 3500 to 4500 rpm. If I kick it at 50 mph it will backfire and pop under hard acceleration. I don't drive my car hard, so I didn't think much of it. No changes have been made to the timing since i swapped carbs. Check the back fuel bowl and see if its getting gas in the bowl at all. Dec 27, 2009 · it was kinda cool at first but soon figured out its not good. . Apr 6, 2013 · Engine backfires under hard acceleration. Ignition system leaks can also cause backfires at idle. Troubleshooting - backfire through carburetor. Last week I finally got around to install my long tubes headers with catless mids. I found the partial problem to be a fuel filter. I am have trouble with my 327 backfiring and popping under acceleration. As a result, unburnt fuel and air will lead to the hot exhaust, and Oct 10, 2015 · 10-10-2015, 08:32 AM. We usually refer to an exhaust backfire as a "backfire", and backfiring through the carb as "spitting" or "coughing". Its very random with the edge on level 1, but gets much worse when I turn the power up. So driving down a back road today, we come up behind someone doing 20 in the 45 zone, I wait and when it’s clear pull out and let her rip. Past mid throttle to WOT, there is a lot of backfire in the exhaust. Feb 22, 2010 · Backfire while accelerating hard? Jump to Latest Follow 11K views 27 replies 15 participants last post by stEVOlution Z Jul 7, 2021 Jul 24, 2017 · 3M VHB 100x200mm~ (4" X8") Double Sided Foam Adhesive Sheet Tape 5952 Automotive Mounting Industrial Grade Very High Bond 5952 (1 Sheets 100x200mm) $7. After doing some investigating I found the wire going to the knock sensor was broken. Sometimes, locating the source won't take you much time, other times it can prove difficult. It has ported 882 heads that are freshly decked with new valve guides, valves and springs, new cam and lifters and new intake with a Holley 675 carb. . I recently purchased this, and have been learning a lot about boats (love this forum). 89 fox body randomly started backfiring and misfiring on hard acceleration timing set at 14 degrees gt40 heads and 650 double pumper on it plugs and everything less than 6 months old only backfires under hard acceleration. Success is getting what you want but happyness is liking what you get. A "lean" mixture is one that doesn't have enough fuel, and too much air. If moving at a. a faulty sensor. I have an edelbrock performer intake and 600 cfm performer carb. 2004 - 2008 Ford F150 - misfire backfire problem solved - went threw all the first causes of this problem coils/plugs/MAF ext next thing on my mind was cats internal fuel filter malfunctioning o2's kept checking stuff and then checked the pcv and vacuum system. "Backfiring" is usually caused by a spark plug "sparking" when it isn't its turn and the exhaust valve is open. The tech thinks it could be a broke or weak intake valve spring broke or slightly twisted causing it to not close completely. Video. 1) pulled the ecu out so I could see the diode and set screw2) made sure the screw was all the way counter clockwise3) started the car4) turned the car off, turned the key on5) turned the screw all the way clockwise until it stopped6 Jun 10, 2014 · My 8 speed automatic, non Z51, 2015 C7 Convertible recently started backfiring in Sport mode during hard acceleration 0-60. May 14, 2013 · The backfire on hard acceleration is almost always pump shot related and there is not 1 correct answer. This seemed to help out some, but it still backfires periodically on hard acceleration. #1 · Jun 20, 2013. If this sag occurs at an already LOW engine RPM the momemtum of the engine in a negitive direction cannot be overcome with added fuel and a STALL occurs when you de-clutch or pull the clutch in. Dec 12, 2018 · Rrworker [OP] said: ↑. Apr 22, 2024 · Causes and Solutions. Under hard decel you go into this decel fuel shut off. 3 vortex engine on acceleration backfires at about 3000 rpm. Aug 25, 2011 · The best way I know to find an intake leak is to spray (unlit) propane around the intake with the engine idling. 29 posts · Joined 2015. have to crawl through any intersection until it picks up a bit of speed from idle. I recently noticed that during acceleration, my car would shudder a bit. Like. Sep 15, 2012 · 1 / 1. However, many times, for different reasons, the air fuel mixture may become too lean (more air and less fuel) or too rich (more fuel and less air), and this leads to backfiring. #15 · Aug 5, 2009. When you changed the pump cam did you check the linkage to make sure there was no play in it. Bill Tichenor. Sounds like a spark issue to me. Oct 20, 2022 · A loud sound through the exhaust pipe at idle tends to occur due to a sudden fuel pressure drop which affects the fuel-air ratio. Mar 8, 2019 · 1967 - 1972 F-100 & Larger F-Series Trucks - 390 backfires under hard acceleration - Hi my 390 with new 600 cfm carb and new intake manifold backfires on hard acceleration and bogs down, but with gradual throttle will will rev freely, albeit with a hard time reaching 5000 rpm, timing set to 10 degrees, any ideas? Dec 2, 2012 · It had an edelbrock on before the Holley that didn't pop like this so it's not the motor itself. It also seems to be worse after the engine warms up. I see lots of noise in my AFR. Usually that means a lean condition exists. idles smoothly, and it runs fine once it's above about 5-10mph or so. It happens the second I get off the gas leading me to believe it has something to do with the blow-off valve. Cruising along at moderate RPM, it runs well, with an occasional bump from a misfire. Aug 10, 2009 · SHADOW 1100T said: 2 things that will cause that, carbs out of sync and the idle needles are in the stock position, they need to be 2 1/2 to 2 3/4 turns out from seated. Backfire is caused by combustion in the intake manifold. Go inside the car, pull the carpet back and put a nut on the bolt that you have installed from the motor side of the firewall. Aug 4, 2015 · backfiring through the carb is usually caused by a lean condition. First check all the valve lashes then look for any intake leak like a TB boot. If your fuel filter is dirty or clogged Oct 19, 2023 · Harley Davidsons backfire because of a little explosion in the intake or the exhaust. Sounds like you have a bad spark plug or wire. 12/02/2009. Nov 19, 2017. Jun 19, 2011 · The popping and backfiring indicates an ignition problem so make sure your spark plug wires are separated and are in good condition with about 25,000 ohms each. #6 · Oct 13, 2011. Only way it would run decent was with the a/f screws 4. When I first start the engine it runs great, and idels in great. Otherwise, the motor runs great, idles smoothly and has reasonable power. Check your plugs for fouling, and then check voltage on the coilpack. I spent some time on it this week rebuilding the carb Dec 3, 2010 · Check behind the spot and make sure you aren't going to drill through something expensive. Mar 21, 2011 · Apparently a 1 piece plug to alleviate breaking them off. This can also cause your engine to backfire. This is why you HAVE TO DRILL the 1/16" intercooler weep hole. #1. I played around with the timing and it 6. Sep 8, 2014 · If a hot wire in your electrical system is hitting a exhaust manifold,shorting to ground it is almost like shutting off the ignition while crusing at 50 mph. But if your in neutral and start revving it, around 2000 rpm it starts popping out the carb. Jul 3, 2018 · Sudden loss of power on hard acceleration. I am running a Mallory Unlite with vacuum advance. The vacuum advance is working properly. If the problems persist you can start messing with pump cams, squirters, jetting etc. Don't mean to sound short but there is a lot of info and I'm going to try and keep this short. Nov 24, 2011 · backfiring on deceleration. Less fuel is given to the combustion process, decreasing the efficiency and leaving unburnt fuel behind, causing an exhaust backfire. The engine still stumbles and backfires through the carb. A car backfires when there is unburnt fuel in the car’s exhaust system when the car’s spark’s plugs ignite the fuel in the cylinder. Then look for a partly plugged injector or low fuel pressure. Under normal driving it runs perfect. I noticed when I let off the throttle the AFR leans out to about 34-35ish after a second or two and that's when the exhaust would have a loud backfire/pop. i took the tuner out of the truck. If you have a vacuum leak at the throttle body to manifold, which is common, or anywhere else, that may be causing lean pops too. I feel it a lot in stop and go traffic. 503, Duration at 050 inch Lift: 218 int. Later I noticed the Service engine light on so I pulled the codes and the only one present was a code 43. Problems with any of these components can cause your vehicle to hesitate when you try to accelerate. steady speed, and I give the truck gas to accelerate, it hesitates and backfires before. It almost seems like its getting choked when i press ******* the pedal but comes back to life and idles perfectly when i take my foot off the pedal Apr 13, 2024 · Some of the most common causes include issues with the ignition system, fuel delivery, sensors, control modules, circuits, and vacuums. I have to mention that at this time there was a leak in the exhaust manifold. Mar 11, 2008 · old s-10 owner. I recently ran into both problems with miy vehicle. I have fixed a lot of these type issues and it is usually a combination of the correct cam and shooter size. or some other system fault. 10 min read. Ever since changing the exhaust tip, the Rhino backfires when I let off the gas. After that time period or so my truck will lose power and backfire out of the exhaust under medium to hard acceleration and will not run properly until i proceed with moderate to light acceleration. The holley 4160 600cfm vac sec didn't have these popping or backfiring issues. Aug 31, 2015 · 540 posts · Joined 2008. - Gm zz4 grate engine. I put an aftermarket billet exhaust tip on the exhaust. 040 over rebuild. The CEL will start blinking. Holley truck avenger 770 (new) Oct 12, 2018 · You still need to pull the covers and check (esp. Common causes include problems with the fuel system (like clogged fuel injectors or a dirty fuel filter), ignition system issues (such as faulty spark plugs or ignition coil), and incorrect engine timing. 580 posts · Joined 2004. It doesn’t backfire after light acceleration only after hard acceleration, has 3000 miles on it. I have to believe that for it to go that lean it's by design for the system. When the ratio of fuel to air is either too rich or too lean, the combustion process becomes unstable, leading to backfires. Jun 20, 2013 · K. - 200 r 4 transmission. SEND THE COPS! . Pops back through throttle body on hard acceleration. exhaust valves) valve motion, either cranking or idling. You need to grasp car backfire meaning to understand its causes. The first step in stopping a car from backfiring is to identify the cause of the problem. I have a sbc 307 w/ edelbrock performer intake topped off with a holley 670 street avenger carb. I changed the plugs and wires, checked the cam lobes, and cleaned the carbs. I got a 2018 Ecoboost, and it's tuned and FBO. Attached Files. My Videos on You Tube. #12 · Mar 14, 2008. I recently installed a summit k1101 cam with 194/204 degrees at 50 thousand. Engine backfires can be produced by: a vacuum leak. We cleaned maf, replaced fuel regulator, replaced a cracked hose on intake. I have a 1978 302 in a 1926 model T. If you go any more it backfires through the exhaust. Now getting a backfire through the carb (seems to always be the one over the 5/7 cylinders) on acceleration. Interestingly I had never used Track mode before, and shortly after using track mode, the car started backfiring in Sport Sep 27, 2017 · by farmallmta » Thu Sep 28, 2017 8:03 pm. Reply Like. It backfires as well. This is what causes the misfire. I put in a points distributor and there is no change. Had the timing belt replaced, runs stronger than it did but still has the popping on hard acceleration. It would sputter (idling) at 20 psi. Older vehicles are more prone to car backfires Jun 22, 2017 · Received 32 Likes on 29 Posts. #2 · Nov 12, 2019. Inspect the whole EGR system, the position sensor, the EGR valve and the EGR soleniod. For my truck it was 35 idling. - Hooker headers. 32 posts · Joined 2011. This can happen under load when: 5) vacuum advance diaphram in the distributor is leaking, failing to advance the distributor when you require. ketchum Discussion starter. With the timing, float level and accel pumps set correctly take it for a test drive. It had not done this for 6 months and then it started. I have progressive linkage that should kick in around 47% TPS, but I can't even get to that much throttle without a backfire. Knarf0486 Discussion starter. If you do this, and change spark plugs every 30k miles, you will never have a misfire ever again. I have a 03 foreman 450 and it seems really cold natured. Running Low-Grade Fuel. I will have to check the idle screws. It's a 302cu". Not only can a rich air/fuel ratio cause a backfire, a mixture that doesn't have enough gasoline can cause a backfire, too. The stock tune is for 87. The first few times it happened while trail riding I actually looked around to see if someone was shooting at me . Dec 11, 2023 · A Harley Davidson motorcycle cutting out and backfiring can be caused by a variety of issues. #1 · Feb 18, 2010 (Edited by Moderator) I have a 06 Brute Force 750 and it pops in the carb at 1/4 throttle. Any help would be great. Jul 5, 2011 · This helped. Usually the backfiring is more severe under hard acceleration when the carburetor is lean due to fuel supply. Engine ides rough when heater controls or air condition is on. The only difference between stock and the billet tip is increase from approx. Remember, the root cause of ecoboost misfire is the condensate buildup from the intercooler. The other day, when I was changing my oil, I checked my catch can, and there were bits of metal on the bottom. lean or rich air/fuel mixture. Dec 7, 2008 · Sounds like the EGR may be sticking open, causing the computer to think the truck is running lean. - Edelbrock 750 carb. When the throttle is completely closed, you should read less than 1 volt. Installed mimb snorkel, dynatek cdi and a stage 1 dynojet kit. This mini-explosion can be quite scary for a rider and people around the bike. 95 should be good. If I accelerate slowing it seems that does not exhibit this issue (so far). Accelerated normal and hard as usual, then in middle of 4th gear it falls on its face. Runs great until you floor it and it will backfire and pop through throttle body. And under hard acceleration it does it even worse. Jul 29, 2007 · With your vacuum advance disconnected and plugged at the carb or manifold warm up the motor and hook up the timing light then accelerate the motor and see at what RPM the advance stops and what the max timing is. Dec 8, 2009 · 103 posts · Joined 2010. I have headers with dual 3" exhaust and an H-pipe. If it's over, try loosening the screws on your TPS and see if you can turn it until it goes below 1 volt. Idles fine, cruises fine, no blowby, runs good. levisnteeshirt said: i'd check the float levels in the carb ,, but really i'd go over it from top to bottom. 15 Z Force 800 EPS . When you get going even after it warms up if you accelerate hard and coast down without downshifting it lets out a backfire. Also I suggest cleaning your computer plug-ins with contact cleaner and then re-connect them several times to ensure a good connection. Mar 18, 2007 · Rhino backfires. 538 means you did something wrong during the engine running test. Check Your Fuel Pump. Apr 28, 2008 · A lean fuel condition can also cause backfiring on acceleration. I tried cleaning the carbs, adjusting the pilot screws, synched the carbsstill popped like a bugger. Jan 19, 2004 · Re: Engine cutting out, backfire on hard acceleration (elwesso) Post by desertq45 » Mon May 14, 2007 6:55 pm. Mar 18, 2016 · Hard Acceleration kills engine and backfires. During the process, I opened up Sep 15, 2022 · 3. picking up the speed. As I retarded the timing closer to where my engine likes it went away. All recently rebuilt. None of this solved the problem of intermittent bogging down and then a pop out through air intake when in gear and slight power load. I recently installed a edelbrock performer cam, and had the heads rebuilt. Lately, it won’t idle for more than 10 seconds before it’ll stumble hard enough to die. My '86 VT1100 had the same problem with backfiring on deceleration. If your car backfires, key culprits include engine timing issues, fuel mixture imbalances, damaged valves, ignition timing problems, and spark firing order errors. Lean Air/Fuel Mixture. Another source of a porblem might be a vacuum leak causing the engine to run too lean at idle. At first I checked to make sure all cylinders were firing to which they were. 89. As mentioned above, if it's "backfiring" through the throttle body, odds are you're running lean causing lean pops. #5 · Sep 1, 2015. I can't figure out what's happening with my sbc 350. It is only after I twist the throttle for about two seconds that Mar 11, 2007 · Put in too much fuel and the RPM rises, and too LITTLE the RPM sags. SBC 283 with 4 Holley 94. Jul 30, 2022 · Sbc backfires through carb under acceleration. A simple trick to see if you have lean fuel condition at idle is to lay a shop towel across the carburetor air-horn. Bad sparkplugs are a notorious culprit when it comes to engine misfiring. SHARE POST #15. Made merging into traffic downright dangerous. Motivx Tools Oil Filter Wrench for Toyota Camry, Tundra, Tacoma, 4Runner, RAV4 and More - 64mm 14 Flute Precision CNC Machined Aluminum Oil Filter Removal Tool. We timed her up and made sure that it was running 8 degrees advance. Apr 23, 2012 · sbc 307 backfire on hard acceleration HELP!!!! Ok guys this is my first post!!!! Glad to join the forum. I'm working on a 1986 Dodge Ramcharger with a 318. B. If the wires are bad, they won't deliver properly, and if the plugs are fouled, they obviously won't ignite properly/at all. 17 posts · Joined 2011. Try it sometime it will backfire thru the exhaust and blow the muffler up like blimp. For example, I'll be going 60 mph, hit the brakes, and start accelerating again with light gas pressure and it will hesitate like crazy. ran seafoam through the vacuum system problem solved Aug 24, 2015 · Here's a list of major news parts: - Heidts Superide II front clip. Sparkplugs are an essential part of your engine, with the job of generating an electrical spark that ignites the fuel in the cylinder. Joined: Nov 11, 2006. - After driving very smooth for the first 300 miles, I tried medium acceleration today. Such a mixture could be caused by low fuel pressure due to a failing fuel pump, a clogged fuel filter or clogged fuel Apr 8, 2023 · Let’s put a single backfire after hard acceleration after letting off throttle, did notice carbon build up on the upper cylinder while changing plugs, gonna run a can of sea foam with about 1 gallon of gas and hopefully that will clean that out. Check your fuel pressure 1st. There's no flames, just a pop and maybe a little puff of smoke. #1 · Sep 13, 2010. But there is a lot of hesitation and stumbling on reacceleration after driving 40+ mph. 2004 - 2008 F150 - Hard Acceleration Backfire - I have an 04 SCREW with the 5. This leads me to think its a fuel problem, but its never set off an engine light for misfire. This is not a gurgle, it is a very loud bang. 4. Another common cause of engine hesitation is a clogged fuel filter. Nov 19, 2020 · I can accelerate from 0 to whatever with no problems. Oct 13, 2016 · Backfire! (long) I’m experiencing occasional backfire from the drivers’ side; typically about 3-4 seconds after heavy acceleration if you let it drop to idle speed. Once warm, it could only be babied at the gas pedal. Carburetor Installation and Tuning. Three backfires through the intake between 30 & 35 seconds during moderate acceleration. Camshaft broken in well, no ticking, may be a roller camshaft, unsure, engine was assembled minus when I got it. #2 · Oct 28, 2015. I have a 2007 660 Rhino. Sep 13, 2010 · 214 posts · Joined 2009. A rich mixture can result from issues such as a clogged air filter, a malfunctioning fuel Nov 6, 2022 · Tweet. Any hard acceleration, and it would bog down/stall/misfire. Sep 8, 2004 · Hi guys I have been having a problem with my chevelle backfiring after a heavy load. Feb 11, 2020 · Moderate to hard acceleration causes a backfire and the engine dies. Instead of backfiring all the time when accelerating, it is only doing it when I accelerate hard. Thought I had it, but alas seems to change its mind if I look at it funny. I only had a CEL after one stall, then it went away after a few minutes by itself. Montevideo, Uruguay May 21, 2015 · Popping/backfiring while accelerating, help! Hey guys I got a 2004 M6 GTO that's basically stock with just a muffler delete (I know I know muffler delete = clown shoes) but I got the car like that and it sounded great and I was always complimented about it. 14 posts · Joined 2010. It idles smoothly and revs fine in park. 50 int. 2004 - 2008 F150 - backfire under load during aceleration - i have a 2006 ford f 150 with a 5. If you let off the gas for about 20 seconds problem clears power is restored but will bog down again about 20 seconds later under load Nov 25, 2020 · As others have suggested, either drain the gas tank or use up the fuel down to 1/8 tank or so and refill with 87/89 octane. In rich or lean situations, the combustion of the Nov 10, 2017 · It was easy to start when cold, but hard to start when warm. video. 40 on hard acceleration (had gauges inside the truck on long hose). Has 60 psi fuel pressure, IAC Position 5% at idle. If your fuel pump is going out or your fuel filter is clogged up your fuel pump may not be able to send enough fuel into the air intake of your engine cylinder. 1 turn out on all 4 seems to give the best response. After it pops it pick up and goes. I have an 05 Titan SE 4x4, the body has 150xxx miles and I just did an engine swap after I blew mine. Hey guys. an exhaust leak. Check for incorrect spark firing or rich/lean fuel mixtures that impact combustion efficiency. Chevron Techron Concentrate in my case) before moving to more expensive diagnostic options. Air intake problems and exhaust leaks can also Aug 2, 2009 · 476 posts · Joined 2008. sometimes it wont pass 3000 rpm it just stays there and backfire and have no Mar 24, 2004 · seem to disapper under hard acceleration (maybe 3/4 thorrtle) but it feels like it wants to backfire through the carb or it does. If you have never replaced your fuel filter before it may be a good idea to inspect and replace it if necessary. Also, I have noticed that when I start my bike, only one cylinder fires. I have a 1979 Ford F150 strictly on propane. I managed to get the truck running and she sounds amazing again. 1” to 1. problems in the ignition system. Decided my best bet was to tear the carbs down a second time and give them a once-over again. I did notice one day as I was playing with my timing that when I had it a little too advanced it started to backfire out the exhaust. Feb 18, 2010 · K. Nov 11, 2019 · 15344 posts · Joined 2008. Check the inside of the distributor cap for moisture or carbon tracking & replace if required. Exhaust backfire on deceleration. It may even be a bad injector . and forth, and the MO will accelerate matching the engine rpm's until I let off the gas. Okay, I've been searching like crazy and talking to everyone I can think of to fix this problem. Older cars backfired AFTER hard acceleration was let off, but the XJ-S has overrun valves to cut fuel and prevent this. 503/ . Feb 7, 2024 · 1. Oct 6, 2019 · Exhaust popping under hard acceleration. Exh. It seems. #2 · Feb 12, 2010. Hey guys, IÂ’m hearing popping/backfire only under hard acceleration, usually starts after 3000 rpm, and only hearing it from the passenger side pipe. It only burns after being discharged to the exhaust manifold, which is very hot. Only two vacuum lines: one to the Vacuum advance which has no leaks and visibly advances the distributor to the full limit and the second to the vacuum wipers (currently capped off so no vacuum leak there). You should hear a slight bump in the rpms until the ecm makes corrections. You need to set the float level and properly adjust the accelerator pump (s). 5" PV Oct 19, 2020 · Backfire on Accelerataion. An improper fuel-air mixture is one of the primary reasons behind engine backfire through the intake. Help. garyf, Sep 8, 2014. Feb 11, 2008 · This past week I have started to notice a surging when I acceleration hard. bad timing. Usually 34-38 degrees at 2200 to 2600 RPM. Exhaust backfires can also occur due to wrong or late ignition timing. Just went for a good drive. This explosion is supposed to happen in the combustion chamber of the Harley. 4 Triton 3v engine and every time i floor it and the engine reaches 3000 rpms the truck backfires and looses power. Tighten it. Had it on the lake last week, and it would bog on acceleration from time to time and would not drop below 3k rpms after shifting back into neutral. Jul 20, 2008 · Hello, I've got a 1987 Mercruiser 140 with the Mercarb. I have to replace the valve cover gaskets because they've been leaking and another tech Oct 28, 2015 · Oak73 Discussion starter. Oct 10, 2011 · On my 1999 chevy siverado 5. Coilpack could be going bad causing it to be sending weak sparks. As the title mentions, I have recently developed problems with an occasional but LOUD backfire on hard acceleration. That will get you into the area where the leak is. carburetor tuning and adjustments. berniematic. The timing was set to 8 degrees before TDC with the vacuum hose to the advance disconnected and blocked. The dwell was set to 30 while the vacuum advance was disconnected. Apr 20, 2014 · Ed98 said: Now if you start the truck and idle it--highest possible vacuum influence--you will get a downwardly adjusted pressure, something less than that reading above. If I drill it off the line it will turn the tires and run out well. Bought an 06 BF 750 that had a stubble and backfire on hard take offs. The most common reason a car will misfire under load is faulty sparkplugs. The truck. The motor and carburetion is bone Jul 9, 2021 · Trying to run it at high RPM, it’ll either buck repeatedly, stuck at 4k-5k RPM, or buck a time or two and then continue on up to redline. Backfire after hard acceleration in a car can occur due to a few different reasons: 1. Feb 18, 2008 · I'm getting a backfire through the carb under acceleration (part throttle or WOT) off idle. Drill a hole and attach a new ground cable from the firewall to the frame. Backfire BEFORE acceleration sounds like – Luis Gasperini / '91 V12 XJ-S conv. I checked the vacuum advance next and the diaphragm was shot, so I replaced the vacuum advance. 7:1). Drivetrain specs as follows: 87 truck 460. On cold winter day it started to backfire going up a hill and then every time I gave it gas. I'd also check the TPS for proper function and adjustment. Improper Fuel-Air Mixture. At each pop I can feel an extremely brief loss of power, similar to a misfire. The backfire happens near WOT in 3rd to 5th gears. Backfires can be caused by several issues, including a bad spark plug, incorrect timing, problems with the fuel injection system, or a malfunctioning exhaust system. Apr 4, 2010 · Backfire on acceleration through the exhaust points to timing or a valve or lifter or bad plugs ie (cylinder not firing every time then when it does fire it also ignites the unburned fuel in the exhaust manifold! this is a serious condition and does require a dealer visit now! AIRBORNE. Mar 23, 2004 · Propane Engine backfiring. If it sounds good at idle , but not May 9, 2017 · 06 brute force 750 stumble and backfire. Jun 2, 2005 · Use a digital voltmeter set so you can read a range of 0-6 volts or so. 85 to . Oct 2, 1999 · Backfire in the exhaust would be rich mixture leaving unburnt fuel that detonates in the pipes. Questionable builders use questionable parts and who knows what they do to break-in a new engine/cam/lifter set. I changed the filter and the problem got better but it didn't go away. As I advanced it more the backfire got worse. Under hard acceleration it stumbles and lacks power. If it's still misfiring/backfiring pull the plugs and check them for fowling. Another motorcycle backfire cause has to do with the quality of fuel you're using. Mar 29, 2006 · The vehicle is a 70 El Camino SS 396 with a Q-jet carb. The motor is a hydraulic lifter 1961 230 HP 283 Apr 7, 2017 · 8. Mar 3, 2023 · 1) Worn or Dirty Sparkplugs. After some relatively hard acceleration I am experiencing a loud pop, sounds like a backfire but I'm almost positive it is coming from the front of the car. Under load it backfires through the intake. In general if the engine backfires through the carb one or more intake valves is open during ignition on one of the cylinders. When I put the car in drive and get down the road 100 May 8, 2019 · Backfire during acceleration. It is normally due to an interruption in the engine’s operation or exhaust system. Jul 31, 2021 · Thus if you are asking what causes a car to backfire on acceleration, it occurs due to unburnt fuel in the combustion chamber. It has to run for about 15 minutes before it starts to pull itself good with out weezing and cutting out. If you're running low-grade or dirty fuel in your motorcycle, it can cause all sorts of problems, including backfires. These issues disrupt combustion, leading to the distinctive sound. 84/1. Has 187 58cc heads from a camaro with 1. Carb investigated and accelerator pump is works fine. roller timing set (early set, not 8 deg retarded) Hydraulic Flat Tappet cam, Duration 276/ 286, Lift . Weiand Stealth Intake. Felt like I either snapped and input on the tranmission or lost a boot off The motorcycle is designed to ensure the supply of the air gasoline mixture to the engine in a proper ratio (14. itreccptwuyduvduhidg