lol and id be broke....at least this way i get to learn, and save money.....besides a mechanic would set the timng to like 2 degree advanced, not drive it, and charge me 60 bucks....and id still be out on my front yard with a timing light

 

you might be lean..are you running the stock injectors?

 

yes im running stock injectors--is utterly amazed at the response rate of this post, now its to the point that we all just post here cause we are bored lmao--OH i had some crazy *** guy chase me for 15 miles every turn i took, i was like WTF......so i hit the highway, and hit 130, ..--i think-- speedo was burried beyond the 110 heh...

 

gotto the Other board and see if they can help ya out.....Im thinking you need more fuel..but I dont know much about this deal...

 

i thought backfire was too much fuel and it igniting off the headers.....that or the spark isnt burning all the fuel that is delivered and the excess igniting in the headers....thats why i think its my timing....

 

so basicly what i need to know is, ..do i advance, or retard the timing to get the spark to ignite all the fuel.....

 

you said you have an adj. fuel pressure reg. now, try lowering the fuel pressure. Maybe you have too much fuel. I have yet to add any fuel to my set up at WOT, and I'm even still considering taking some fuel out.

 

i never said i had an adjustable fuel pressure regulator lol.....i dont have one

 

if you set it to 0 degrees with the wire plugged up that would be why its running like crap. I didnt read all the post but you have to set base timing with the wire disconnected.

 

Maybe I don't quite understand what is going on here but....
Is the huge backfire come when you HAVE your foot ON the gas, or is it when you do not, like on de-celleration?????

 

yes i unplugged the tan wire with a black stripe on the left side of the heater box......and its on a deceleration 330...thanks for asking that in-case someone got confused....i forgot to mention that crucial part

 

You should not have any major problems.

What kind of exhaust do you have? Flowmaster? A free flow exhaust tends to produce a backfire on deceleration sometimes. Especially with bigger cams, so you should be fine. How loud is the backfire, like a shotgun or a BB gun?

Do you have a cat? If you hollowed out your stock cat, thats probably why it pops. My car does the same thing, it gets annoying but whatever, a beefed up smallblock is not a smooth running Cadillac Northstar. I can deal with it. I have a hoolow cat too, they tend to produce that popping effect. The more you advance your timing though, it sould dissappear.

You did plug that wire back together didn't you? You need to do that if you did not. one way to make sure you un-plugged the right wire is to un-plug it while the motor is running, with timing light in hand and looking at the timing mark. You should loose about 4-6 degrees of advance when you un-plug it. You can plug it back in while it's still running too, it should not hurt anything.

 

guess my sig doent show up this far down in the post, .ok here goes....eelbrock TES headers, 3 inch pipes gutted cat flowmasters, open air element, LT1 cam --the backfire problem started after the cam install actually-- and i had a guy write me a chip for when i was done with the cam, its in the car now...the backfire is like a shot gun lol., the bb gu popping i can deal with, and i actually like the sound of that....its just that one single loud POW in mid deceleration after a good 60-100 mph run....THAT scares the crap outta me....i could definatly live without it, .....its hard to go 'yeah i whooped you ***' and feel good about it , if your car gives a victory noise proclaiming "KAPOW!!!' ...or when it does it with a girl in the car after showing off, ....lmao, its just gotta go man heh and yes, the wire is plugged back in --nods-- i woulda noticed that SES light if not...

 

ps. i dont consider my 305 beefed up , just half way moded lol.....when i have 330 hp like you THEN ill say beefed up

 

LOL, sorry, my SES lights are always on in my cars. Forgot what it looks like when they're off. Know why? cause I rip all that BS out and put the reliable basics on.

 

Are you sure...Like a shotgun? Cause mine is just like a high powered BB gun, not a really loud " KAPOW" like you are talking about. Not to mention it gets worse as I retard the timing.

Does it backfire a little bit when you rev the crap out of it in neutral or park? Like when the rpm's are coming back down at say....2500 rpms or so?

 

yea but its more of a rumble, not a loud pop,just a few small pops the backfire on the highway after a good run is seriously like a shot gun....

 

Weird....must have something to do with late fuel coming into the cylinders after you run....I don't really know what to tell you...maybe a EFI guy has more knowledge on it than me.

Did you change your plugs? What did you set the gap at?

 

eh...i thought they came pre gapped, ...i could be seriously wrong and im sure i am, ...and ill feel damn retarded if so....what should i set the gap at???

 

why do i feel liek im learning everything bass ackwards here, ...i did a cam swap easily and well, and i dunno how to set plug gaps or timing, anyone see anything WRONG with this? lol

 

Try both chips and see if there is a notable difference now that you have everything set.

I would assume the bang-pop is worse with the stock prom than the custom one because you get less full advance from it.

Try it out.

 

true, ..worth a shot at the least , if nothing changes, i go back to tinkering with the timing..

 

Don't worry about it, we all learn some things first and others later.

First: what plugs did you get?

Second: gapping is as easy as wiping your ***. You get a little gapper from an auto parts store for 99 cents. It has numbers on it. You gap the plugs to the # you want.

Third: gap them to .45, stock is .35 but that is stock, which you are not. .45 gives you a hotter spark.


You could have a plug with a really small gap in one cylinder, and it's not burning all the fuel....deceleration.....BANG-KAPOW-POP!!!
LOL!!!

 

Remember to unhook your battery for at least 2-3 mins. to clear the ecm when you swap chips.

 

yeah i disconnect the batt every time i pop the hood for some reason, just incase ya know...i have the V gap plugs, ...the V is cut into the uhm...i dunno what its called.... not the L piece that hangs over, but the thing that the l thing hangs over

 

Are you talking about NGK V-power plugs?

I thing they come pre-gapped. But just in case you should always check the gaps to be sure.

 

i think thats them, ...the gap isnt in the overhaning L , just the eraser looking thing under it.....they all --looked -- the same gap but you cant really tell by eyeing it, besides im sure they are gapped for factory specs....

 

Well, factory gap for the LO3 is .35.

You NEED to be running .45. Since you have headers it would only take you the better part of an hour to gap them. And 99 cents . Go ahead and gap the plugs, then see if the problem goes away.

 

aiiiight, hell why not, ive taken everything else off the engine short of taking the whole thing out this past 2 weeks....wow, ...2 pages, my first sticky post woohoo....so yeah, ill do that tomarrow as i try to figure out wwhy my rear end sways at high speeds....

 

Good luck buddy...hopefully I was able to help you some.

 

To me it sounds like his spark plugs are getting too hot and causeing that cause thats what mine did untill i fixed my timing on my beast

 

those would be called Splitfire and they SUCK..I doubt if thats your problem...but worth a try...also, any chance you have a vacuum leak??? This will also cause a backfire. Are All the vacuum lines in place and good? Did you torque the intake to spec, and in proper order....I think you have pretty much ruled out timing...and a backfire like you mentioned is by no means normal...and you shouldnt...just live with it....No flame 330hp, but dont give up on him yet...

Intake Backfire:
A. Improper ignition Timing (ruled that out)
B.Defective EGR Componant.
C.Defective TAC Vacuum motor or Valve.(dont ask me)
Exhaust Backfire:
A. Air leak into Manifold vacuum ( leaning towards this)
B. Faulty air injection diverter valve.
C.Exhaust leak.

Ive also seen an electrical short cause a backfire.
From your description I am saying you have a exhaust backfire....check the vacuum at your intake.......

 

And a little prayer to the Please help me fix my car Gads might help,.,,,:lala:

 

lol you wouldnt believe how manny times i checked every hose, ill go tighten all the bolts on the intake in a min, ...i used half a tube of gasket sealent on the manifold when i put it back on, ...sealed both sides of the gasket, ..i have orange sealant all over the place!! lmao...so i dunno if its that....ill try anything though...oh and the plugs arent splitfire, they are called V gap....they dont make a splitfire for my car, i asked once

 

lol oh the joys of headers never end....turns out 4 of the 9 bolts ive tightened so far were loose enough to unscrew by HAND heh, ok now im really going to tighten everything..good call on the exhaust leak....i dunno if it fixed it yet but it needed to be done, thats for sure, ....ill regap the plugs in a lil while, as for now, back to tightening bolts thats impossible to get to on the pass side....

 

If he is not getting a backfire as he is into the gas pedal, in other words...he is not missing throughout the driving range, he is fine, it's something minor. Like a shotgun though....I don't know, I'd have to see and hear it for myself. You never know if it's the plugs or not, he could have dropped one on the ground and closed the gap by accident or something. Or a plug may have loosened up or something.

 

ok im seriously voting on exhaust leak du eto the fact that 6 bolts were loose ...seriously loose, and one was MISSING!!! yes....a guess which one?? only the hardest one to get to , put in , and tighten...the pass side REAR bolt! i just spent 2 hours taking off the y pipe, taking off smog crap, and having to take the pass side header OFF in order to put a bolt back there, ...had to tighten it down half way by hand and slide the C type end onto the bolt --thank *** for the C end,,seriously-- no other way to do it unless you take the air box out.....so....now that its done and over with,and everything is reinstalled and back on TIGHT ...heh.. im going to go get a gapper, and laugh at the extreme easyness of this part of the job....i have one thing to say. tighten your header bolts every 1000 miles!!!! i didnt, ...and i paid for it big time....wrenches went flyin, inanimate objects got kicked.....and i cussed my gf out in the process....time to go kiss *** and resume the project of the day....off i go...

 

Those dang header bolts, I actually have a wrench that I grinded down some to be able to get a 1/6 of a turn or whatever on that last pass. side, I also cut the bolt shorter so I didn't have to turn it as much with the wrench (dirty threads). Hopefully that fixes your problem.

 

ok, every time i touch my car, i find something wrong with it, ...so update. 2 plugs were at .30, 2 were ar .35, 2 were at .37-38, and 2 were at .40. now all at .45.....this better be right cause i dont wanna do it again lmao.....and 2 plugs were loose enough to take out by hand.....whole exhaust is tightened, plugs in tight, all hoses are in tact, .--one of the A.I.R hoses was messed up, ...the 3 way black PLASTIC splitter was melted....curious to know why gm felt that it was a good idea to use plastic on a high heat output source.....who knows. i afro- engineered {knee-grow rigged) it on til tomarrow, who knows where ill find another spliter like that....anways.....time to go check my rear end out a lil bit and see if i can*see* why it sways at high speeds.



PS> those header bolts are in TIGHT now...lets hope i didnt miss one somehow lol

 

I must say, You are very honest when it comes to your car..LOL A lot of people , including myself , might be a little ..to tell all the problems you come up with...anyway, I hope this is a fix for ya..because to tell ya the truth ....Ive lost a little sleep over this one!!!! LATAH DUDE!!

 

BTW dont you work or something? You sure have a lot of time to spend on your car!!

 

It sounds like you are havin a ton of fun...LOL. Anyways, I just finished puting a cam and intake on my car today. I had one lifter rattling and one of the brass plugs I put in the intake was leaking. I got all of that fixed and now all that needs to be done is to set the timing. I'm hoping I don't run into all of the problems you did slowmaro. But I do hope you get yours all fixed. Good luck

 

yeah im sorry abou that everyone lol, any little problem i get , i come here, that should make ya feel good though, knowing that i trust your judgement over my own, and i dont trust anything that doesnt come from here, at all. good luck with the cam and all lol, hope you fare better than i did. most of the stuff that was done needed to be done anyways, i just hadnt realized it yet, i was way too anxious for my car to be "completly finished and perfect" when my cam got in finally. sorry about posting every problem by the way lol. but like i said, i trust you people more than myself or anyone else so....i owe ya. :hail: :hail: :hail:

 

You can never trust a pre-set gap.

So, how's she running? Let me know when you get the plastic piece you melted, cause you shouldn't have anymore probs.....right?

Hopefully the shotgun backfire is gone.

 

ahh!! no help!!! it definatly backfires less though...hmmmmm