I am have a afterfire problem And I just can't figure it out so I brought it to a shop and they are going to see if the dist was put in wrong. I havae tried a new carb, new cat, no cat I have tried a jet chip And nothing seems to stop it. The motor is a new 350 that replaced my old one 305. Thanks The dist has 150,000 miles on it. I only get the backfire while deceelrating

------------------
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.

 

Anyone.

 

Not sure of the question.. are you asking how to tell it's in wrong? Or are you asking what could be wrong with it?

-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.v6fbody.com mailbags

 

I want to know what should be look for in a dist with alot of miles.

------------------
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.

 

I am asking, what where's ? what goes bad?

 

Check the internal bushings for wear by wiggling the shaft while holding the housing still. Should be no observable noise or movement.

Check the cam gear teeth for wear, they tend to get an hourglass shape across the length of each tooth as they get old.

Mechanically, that's all that comes to mind.

------------------
1982 Z-28

See http://www.mycar.net/mafb/registry/detail.cfm?id=276 for details

 

You arent running the cat ,thats where the popping sound is comming from ,I get the same thing on decelleration.

 

I also get that popping sound when I deaccelerate. Other than that my car runs and idles like silk. I dunno but I kinda of like that popping noise /.

 

Thanks guys, i tried explaining that it's entirely normal and no indication of any mechanical defect whatsoever about a week or two ago on my board, but he's oonvinced it's something cuz he's never noticed it before. Funny thing is, i have never not noticed it in a carbed car, and i'm glad i'm not the only one.
Not flaming you, it's your money to waste as you see fit, but there is no cure for it. It's caused by the engine drawing an overly rich mix through the idle discharge ports. And there's nothing you can do to stop it. It is not an ignition problem...ignition problems get WORSE under load, your "problem" only happens when you are under no load.
ed

 

Okay, evil I put a new cat on and it is still there, Ed IAm 100% sure that it is not normal, I have had 2 other motors in it and they have never done this, My friend hs almost the same exact set up and his does not do it, I used to be able to go from 4th to 3rd and the car would come all the way down from 5,000 rpm and not pop once. So I no it is not normal. I do thank you for trying to help though

------------------
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.