Author Topic: backfireing (Read 3340 times)

phlatbed · « **on:** Feb 08, 2005, 05:12:11 PM »

ok so my truck has had some HUGE backfires lately and it is coming from the exhaust, what could it be? ignition timing, or carb? or.......?

79coyotefrg · « **Reply #1 on:** Feb 08, 2005, 05:23:28 PM »

sounds like you need to advance your ig timing , could have a cam retarded too much

scheid6996 · « **Reply #2 on:** Feb 08, 2005, 06:00:24 PM »

well it depends on a few things, but the rule of thumb is if it comes from the carb, its retarded, if its advanced its out the exaust, when does it back fire? like on deccellaration? if so thats an exaust leak

WHITE_TRASH · « **Reply #3 on:** Feb 08, 2005, 06:29:31 PM »

Yup if you have even a pin holeahead of themuffler you will get a wonderfully LOUD bang on decelleration.

phlatbed · « **Reply #4 on:** Feb 08, 2005, 06:59:00 PM »

yah it happens when down shifting and slowing down

Willy Mammoth · « **Reply #5 on:** Feb 08, 2005, 07:34:16 PM »

Almost sounds like valve timing. If you don't have any exhaust leaks I would check the timing chain to see if it has streached. How many miles do you have on the engine?

phlatbed · « **Reply #6 on:** Feb 08, 2005, 08:13:50 PM »

theres about 211,000 on it, runs extreamly stong just the occasional backfire

scheid6996 · « **Reply #7 on:** Feb 09, 2005, 05:22:52 PM »

i dunno thats alot of miles, my 4 banger blew on me after 150,000 but thats mostly my right foot, umm ya check your exhaust, and wut R u running for a muffler, cus like a cherry bomb will back fire no matter wut you do

79coyotefrg · « **Reply #8 on:** Feb 09, 2005, 05:50:15 PM »

you know shaving a head will actually retard the cam, thats why i always install mine straight up, this way my cam is actually retarded a degree or two, this gives better lowend , i bet his chain is stretched enough that his cam is actually retarded 3 or 4 degrees causing a little fire to escape at the end of the power stroke

scheid6996 · « **Reply #9 on:** Feb 09, 2005, 06:07:19 PM »

ya that could be, i wonder if he has a loud knock when he starts it in the morning, cus usually thats the timing chain being loose, and even when its that loose i havent had it back fire, but ya it could be, espetually since he has like 200,000m on it

79coyotefrg · « **Reply #10 on:** Feb 09, 2005, 06:10:28 PM »

yep, trust me mine had 285,000 on the original 20R when i tore it down, but it could have gone longer but it was tired

phlatbed · « **Reply #11 on:** Feb 09, 2005, 07:23:25 PM »

no loud knocks in the morning, i am going to check the timing chain this weekend, and its just a normal toyota muffler

DAWGTOY · « **Reply #12 on:** Feb 10, 2005, 08:40:35 AM »

hey man
check your exaust system closely, it could be a blown exaust gasket or like wt said (even a small pin hole ahead of the muffler will cause a backfire). mine did the same thing, replaced the exaust manifold gasket and it still did it took some searching but found a small crack in the head pipe where tha two pipes go into one, welded up the crack and vala no more backfire.

scheid6996 · « **Reply #13 on:** Feb 10, 2005, 05:24:50 PM »

is it a very loud back fire? like one gig bang, a a few small banks and pops?

79coyotefrg · « **Reply #14 on:** Feb 10, 2005, 05:35:20 PM »

chains about to brake, has effected ig timing

scheid6996 · « **Reply #15 on:** Feb 10, 2005, 05:38:39 PM »

ya maybe, but iv never had that happen b 4, iv hadem get so loose that they chatter under a load, but they havent fucked with the timing

phlatbed · « **Reply #16 on:** Feb 10, 2005, 05:45:08 PM »

scheid6996- its all just one huge bang

scheid6996 · « **Reply #17 on:** Feb 10, 2005, 05:51:20 PM »

ya it could be the timing chain, but thats alot of work, so B 4 u do that, id check your timing, how many degres it is, and wut do the plugs look like, beacuse if your running fat on the fule and retarded on the timing, you can get a backfire, but it does sound like the timing is off, but i havent had that problem with out the chain being hella lose and when its that loose when u first start your truck it will slap for a lil bit, and under a loal it will slap also

79coyotefrg · « **Reply #18 on:** Feb 10, 2005, 06:27:50 PM »

is this all the time, or just when you downshifting?

aka slowing down???

scheid6996 · « **Reply #19 on:** Feb 10, 2005, 06:31:45 PM »

no, just when i was going up a hill, and i never had it back fire

phlatbed · « **Reply #20 on:** Feb 10, 2005, 07:34:49 PM »

Quote from: Glen on Feb 10, 2005, 06:27:50 PM

is this all the time, or just when you downshifting? aka slowing down???

down shifting aka slowing down

Willy Mammoth · « **Reply #21 on:** Feb 10, 2005, 07:44:55 PM »

Somthing I just remmembered, If you drive down the road at speed and turn off the ign and hold down on the gas ( carb model only) and turn the key back on it will explode your muffler. So if you are down shifting and you are running rich you may be filling your exhaust with gas fumes that will egnite with a stray spark or heat sorce from your engine.

ezthere · « **Reply #22 on:** Feb 10, 2005, 07:56:36 PM »

before you adjust anything stick a timing light on it. If you can, get a vacuum gauge and plug that in..

Next consult a detailed manual. Chiltons, there ok. If you can get toyota or better yet go down to the toyota dealer and ask them to print you material,,,

there kicking in..

Ask the dealer to print you a service manual referance. IE timing, vacuum & a TROUBLE SHOOTING guide.. They have them.

TRASH what up

Chuck

scheid6996 · « **Reply #23 on:** Feb 11, 2005, 11:38:40 AM »

see how everyones leaning away from the timing chain, like i said haha

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