Demon Z28

Yup, dumb ole Edelbrock 750 decided once again to belch fire.... only this time it did it a lot longer than a quick one... and the fuel sorta burned off (I couldn't get it to go out so I had to let it sit there)...

Nothing is wrong with my timing, so what de hell could the problem be? I took the advance down a bit and it stopped all backfiring problems I had when revving and driving... but every time I start the damned thing it spews fire like you wouldn't believe...

Any ideas?

Jester

Lean/mistuned/clogged accelerator pump.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

Demon Z28

it being lean would cause it to fire a 5 foot flame up through the carb when it starts? :: ponder::

Its not mis-tuned cause I haven't touched it, and I'm going to take it off in the next few days to see what I can find

It never did it before I redid the distributor, but I didn't screw with the timing at all

Jester

Yes, an extream lean condition will cause a backfire through the intake. Thats usually caused by a lean accel. pump. Thats really the only thing carb related that would cause it.
There can be other engine related causes...screwed up timing, over tightened valves, etc.

What did you do to the distributer exactly...and what is the timing set at?

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

Demon Z28

I did the Pertronix rebuilt kit, Cap, Coil, Rotor, Module, weights, springs, and wiring... before i did that it wouldn't start, after I did that, I get the ability to roast marshmallows...

Before I did it though when it DID run, it never blew through the carb like that... not once... I didn't tinker with the carb and I didn't tinker with the timing at all (although I did go back to the natural springs instead of the copper or silvers because before that it idled at about 250 rpm higher than what it did before)...

and I also don't have a way to test what my timing is at

Jester

The first thing I would recommend is checking your timing. Buy a light..they're cheap, come in very handy, and sooner or later you will need one anyway. That will at least rule out or prove the most likely culprit.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

Demon Z28

I'll see ifn I can borrow a friends soon...

What else could it be though, just out of curiousity?

Its a 1407 ... and I don't think its running lean (might be running rich though)...

The timing is set at what it was before, it idles at 650/700 in neutral (before I put the other springs back on it was at 950)... so I was sorta matching what my previous idle was

Jester

Judging the base timing my rpm isn't the best way..to say the least. Stick a gun on it and know for sure.

Changing the springs does NOT effect base timing. I dunno what, but something definaty isn't right with this picture

Running rich doesn't really have anything to do with the accel. pump. if the pump is clogged or otherwise screwed up, a car can run very rich but still go lean and backfire when the throttle is opened. Running rich will not make it backfire through the intake, altho it may make it fire through the exaust.

Also, make sure you vacuum advance is dosconnected when you set the timing, and connected to a ported source otherwise.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

Demon Z28

those little spring thingies were like 0*, 3* and 13* on the advance ... I put the 13* on for starters and it backfired when reving and acceleration, I went back to the 0* and that stopped but it still blew through the carb on starting it up

The ODB

say, you're not running one of those crane fireball camshafts are you? hehe
what about splitfire plugs?

anyway, i may be willing to buy that Edlebrock carb from you. Let me know.

Demon Z28

nope no crane cam ... and the plugs I've got are the NGK's

When I can get the money for the Demon carb I want, then I'll sell it to ya

Until then I sort of have to let it stay there and hope I can fix me current problems till I do get the Demon

greearhr

Double check your plug wiring/firing order. When you replace the cap you might have got a couple in the wrong hole.

Bear Tracks

Demon Z28

I put them on identical to the old cap...

but then again I don't know the firing order off of the cap (IE don't know which plug/wire per cylinder goes to what part on the cap, I know the order for the engine hehe) ... if my webcam was working worth a damn I'd get a picture of it for ya...

Then again a picture of whats under my hood may scare the hell out of some people

super83Z

Hey I had the same prob. My timing was off. I agree with what was posted above maybe some cylinder wires are wrong. Hvae you tried turning the dist. a little at a time to see if won't do it in a certain position?

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I WOULD RATHER PUSH A CAMARO THAN DRIVE AN IMPORT

1983Z28 350w/ edelbrock performer RPM power package , dynomax shorty headers, 700R-4 with shift kit, 750cfm carb, edelbrock 3" exhaust system, ASCD SS hood, 16" IROC rims.

future mods:
completely done over suspension, black paint with flames, Hurst shifter, dakota digital gauge package, procharger supercharger.

Demon Z28

Anyone know the firing order off of the distributor itself in accordance to the cylinders?

Starting from the front of the cap (with the tach and power wires, which is also pointed at the drivers side area more or less on mine, lol) ... anyone know which ones match which so I can check it??

Jester

Just off the top of my head....but 1-8-4-3-6-5-7-2
#1 is the one more or less facing the #1 cyl.

Demon Z28

ok, so going clockwise you just follow the engine firing order then?

MTCAMARO

iTrader: (1)

Rebuilt my distributor this spring also,stripped it down to the inner shaft,did a recurve(springs)new adj. vac. can.Put everything back in on my marks,and the same thing happened.She backfired up through my edel.1405 and started a small fire.I blew it out pretty easy,but it scared me also.I think i had timing retarded too much,i advanced her a little more and she started right up.I'm telling you,it doesn't take much to put you too far out of time.I'd get that timing light and check your timing ,i bet your not where you think you are.

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86'Camaro Berlinetta SC,former 2.8,now 327 cid with 350 tpi heads(pocket ported)summit k1102 cam,305 H.O. aluminum intake,edelbrock 1405 carb,recurved HEI with accel adjustable vac advance can,rebuilt 700r with shift kit,B&M mega shifter,grant steering wheel,t-tops,american racing wheels,louvers....now if i had fresh paint,subframe conn.,cowl induction hood..sigh..