Okay, well been screwing around with my 84 that I just got (carbed 22r). So anyhoo, one drunk night me and my buds decided to torch off the muffler cause without a tach and it being so quite, I just couldn't tell when to shift. At lease thats the story I'm sticking too! Now I have the cat and a pipe that runs about to the rear tire w/o a muffler.

Now it backfires like hell. Not sure if its a fueling problem, or a timing problem, or a back pressure problem. Cause on the old Swampthing (22re efi) I had a 2.5" straight pipe from the stock manifold and it would purr like a kitten on roids without backfiring like a rice burner.

So anyhoo, was thinkin either running a long straight pipe from manifold, or going with a header and a straight pipe that ends behind the cab. So, yall think either of these will solve the fartin, or should I investigate elsewhere?

I have already replaced the air filter, rotor cap wires and plugs, so I aint think those are the problem...

 

Not sure, Clint. But, where the hell ya been?

 

mine dose the same thing until it gets warmed up I think mine is a combo of the choke and fuel cut solenoid and it might be running rich I have no cat on my truck it came that way when I bought it and there are no cat laws here for trucks.

mine backfires (I know backfire is the wrong term) when I am decelerating at a high rpm it is so loud it sounds like a gun shot some times.

 

grab a old flowmaster from someone and get a header it will get rid of that



no cat flow lce header

 

Dude 80hour work weeks blows, leaves ya no time for carnage! But yeah, first I got a Dodge with a 12v Cummins so I stopped playin with the Swampthing for a while to bomb out the Cummins. Then I got the strange urge to pull an evil knievel with the Swampthing, so I did that... Parent's said they knew they never should have let me watched Dukes of Hazard growing up!

Went to an old cement factory, and jumped a 110' long wall with 21º of incline at 75mph. Hit the wall so hard and fast that it ripped the front axle out from under me, which made me scrape along the wall on the Thing's belly. Never took my foot off the gas, so the rear axle kept gettin power, makin me launch over the wall in a front flipping manner at a good ~60mph by then. Got a good 15-20' of air my friends said (was a random idea and noone had brought cameras or video recorders), and first landed on my hood/roof. Let me tell you about a slow motion "THIS IS GONNA HURT!". Then I kinda bounced again for some more air and just started rollin like a Nascar wreck with beer cans flying around like shrapnel. Ended up upside down in a ditch with the Thing on fire. Had so much adrenaline that I didn't feel the concussion, 4 broken ribs, and all sorts of fractures throughout both legs (the engine tried to sit on my lap during the first faceplant) as I grabbed the beer and climbed out the back to run like hell, figuring it was gonna explode any second. A couple of my buddies there were EMT's, so once they finally got me settled down they ratchet strapped me to some 2x4's as a makeshift stretcher, put me in the bed of a truck, and drove me to the hospital . Did I also mention they were drunk? Haha....

Insurance paid for it all. Apparently my "Braking function ceased at top of hill causing a loss of control. Driver attempted to use an incline in an emergency attempt to bring down the vehicle's speed. Velocity was too great and the vehicle proceeded over the top of the incline resulting in multiple roll-overs".

But yeah, I'm glad I got that real nice super-full coverage. $750,000 worth of damage (bodily, property, etc.) coverages

So now I bought an 84 p/u, and WabFab's biggest lift, gears, and a few other goodies, so I'll be playing with that soon!




But anyways, long story short, I totaled the Swampthing.

 

holy jesus! I DEMAND PICTURES of the swampthing! May she rest in peices.

 

cool story! Sounds like you might need some back pressure maybe a muffler....toyotas dont run well without a muffler

 

Sorry jay, no pictures of the swampthing after... Nobody there had a camera and my insurance company had it hauled away to a collision place by the time I got out so I never got a chance to take any pictures. Do have one of me in the hospital. Was feeling GREAT. Gotta love morphine!

 

wow you must trying out for a crash test dummy job arnt you ?

 

Arn't all offroaders tryin out for that job?

 

Clint, would you mind following up on your backfiring issue? I have the same damn problem, except generally when it backfires, the carb floods out and dies shortly after. Generally after a little 4 tire fire, or an extensive climb up a fairly steep hill. On the other hand, I'm considering getting full coverage, getting my yota to this cement plant you speak of, and...well you know the rest. If the exhaust solves the issue, let me know. Thanks!

Rob

 

Just wow..

And me too, my exhaust um.. fell off.. in traffic.. (sorry whoever was behind me).. But was leaking before anyway and it backfires a lot. I think some back pressure could help, but I haven't tried yet. I half-slapped on a cherrybomb for now. Dunno if it made any difference, at least not noticeable.

 

I have a cherrybomb glasspack installed and was wondering if a glasspack would cause backfiring. My engine has started backfiring (just started, or i've just never noticed before). It only does it at 3000 RPMs and only happens when I let off the gas to shift or slow down. I thought a glasspack was supposed to reduce back pressure.

-edit-

sorry, I should say mine is now "afterfiring". Happens from exhaust on deceleration.

 

just for the record:
backfire goes up through the intake, afterfire goes out the exhaust....
The first is often caused by either a lean mixture or vacuum leaks (which cause a lean mixture) that ignites before the intake valve is closed, or incorrect timing (either cam and/or ignition) which causes the mixture to start burning before the intake valve is closed.
The second is often caused by a rich mixture that either continues burning in the exhaust, or with air injection (i.e.: PAIR) or an exhaust leak, the introduction of air into the exhaust stream provides enough oxygen to cause the left-over hydrocarbons in the exhaust to spontaneously ignite. In the case of EFI, it could be an incorrectly adjusted TPS not telling the ECU the throttle is closed which in turn reduces or cuts the fuel delivery thus avoiding a rich mixture on decel with closed throttle... or a misadjusted or malfunctioning dashpot on the throttle body holding the throttle open too long thus preventing the ECU from cutting fuel.
Reduced back pressure, though not in and of itself a bad thing, can cause a situation where the O2 sensor cannot react quick enough to relay signals to the ECU regarding the mixture (though shouldn't be an issue if the throttle is closed since the ECU should ignore the O2 at that throttle position) resulting in a rich condition at least momentarily until the ECU compensates.

 

After researching, I saw a post where you clarified the differences between afterfire and backfire, that's why I switched to saying it's an afterfire. I learned something new.

So a glass pack could cause an afterfire? I'm curious because the only thing thats changed is the distributor, and ever since the afterfire started I moved it back to exactly where it was before I noticed the afterfire, and it's still doing it.

I'm getting off my lazy butt today and getting the timing light and timing the engine. I just need to know if the glasspack could be causing it because after i time the engine I need to know if it will still afterfire so I don't re time the engine 50 times and not get anywhere because it will still afterfire.

 

Well I did finally do something about the exhaust. Picked up one of those cheap thrush mufflers and welded it on. Can kind of see it in this pics (sorry, never took a pic directly of the exhaust):





It didn't completely solve the "backfire" (w/e abe... Lol), but it certainly helped reduce the frequency and intensity. Plus it was only $20 at autozone, so I couldn't complain.

 

great explanation
thanks

 

Ohhh how I wish I could weld. I'm going to build an arc welder with some car batteries and see about getting a flowmaster welded up. I found a piece of exhaust pipe on my rig that may be causing a leak.

 

same thing happened to my 22r when i took the stock muffler off. I thought it was a back pressure issue turned out it was a cracked diaphragm in my carburetor it was getting raw gas in my vacuum lines and it was running super rich. long story short rebuilt it with a rebuild kit from oriellys runs like a dream now no backfiring.