Just wondering if it was to far advanced or retared, This is on decellration the backfireing thanks

 

and it is above 2,500 rpm

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86Z28, GM 350, Jet perf Q-jet & chip Dual snorkel air cleaner, Edelbrock performer intake, Edelbrock headers, Edelbrock cat-back, Off road pipe, MSD 6AL, Accel Super Coil, Moroso Blue max wires, Rapid fire plugs, Jet fan switch, World class t-5, Hurst Short Throw Shifter, Ram Flywheel, Center force dual friction clutch,Aluminum drive shaft, BW disc rear 3.45's & a posi, PBR calipers, Earls braided brake lines, Polygrapite bushings all the way around, poly tranny mount & torque arm mount, Hotchkis lower control arms & panhard rod, Rancho limiter straps, KYB struts & shocks, Gm Wonderbar, Edelbrock strut tower brace, SSM sub frame connectors, Jamex lowering springs, Carbon metallic brake pads, Crossed drilled rotors, Mobil 1 Tranny fluid & motor oil, GM syntheic rear end oil, K&N, Grant stering wheel, 1,200 watt system, Jet Black Paint, 91 Z28 rims, 92 wing, Tinted windows.

 

sound like excessive fuel is the prob not timing.....

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bought a wrecked(head on,bad)'84 Z28 rebuilt it in'92 parked it in
'93 and ordered a '93 Z28. Got tired of the 4th gen in '99 and sold it and begin swapping in '85 TPI converted to speed density. engine is all stock except for comp cam. body has '86 IROC nose peice,ground fx and IROC wheels/goodyear 245/50's. IMO this car looks and feels more "racey" than my '93 did. and I love driving it. BTW fuel injection is great I'll never go back to carbs.

 

BlackZ....I would have to say retarded. I say this because when I first started up the 305 TPI after modin the top half of the motor I had the distributor out of position in relationship to #1 cylinder. The timing was retarded and I had a couple good backfires through the intake....at one point I thought I had lost the MAF!

I had to turn the distributor counter-clockwise before I got things under control....hence it was running retarded(firing late). And oh yeah....almost forgot to mention that my Jet-Hot coated headers got bright orange while this was going on! LOL!!!!

my $.02 worth

Mike

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1986 IROC
305 TPI w/700R4(ready for the 'retirement' home) & 3.42 open rear(for now)
Performance MODS: CompuCam 2030, 1.6 CompCam roller rockers, 'Wile E.' ported stock heads, ported stock intake, gasket matched stock plenum & runners, Hooker Super Comp headers with y-pipe..all Jet-Hot coated I&O, gutted cat, DynoMax cat-back, shimmed stock FPR, ADS Super Chip, 160 deg. stat., Accel Super Coil, Jet airfoil, K&N filters, relocated MAT sensor, advanced timing.........and I still can't get into the 14's to catch the Roadrunner!!!!!Damn ACME products!!!!!

 

I think he means afterfire (through the exhaust), not backfire. I'm having the same prob.

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87 IROC
350 TPI 5-speed

Edelbrock Aluminum Heads, LPE 219 Cam, Super Ram, SS Wheels, Graphite Leather, etc. Click here to see the rest.

 

I get afterfiring under deceleration some times. I'm pretty sure it's due to advanced ignition timing, which is set at 10 BTDC (it should be 6). Because it does'nt afterfire all the time i figure i'll leave it that way, should'nt hurt the motor (unless i'm wrong).
Any other thoughts!!!!!!

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Sat "IROCkid" Bimrah
1989 IROC-Z 5.0 L / 5 spd

 

Anyone?

 

i have the same problem too. i think it sounds awesome. is that a reason i only get 10 miles a gallon?

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87 Iroc-z and a 77 camaro currently being restored
http://satanzchild.isonfire.com