I have got a 83 HO Z28. 305. The problem I am having is that whenever I downshift and let the motor slow the car, I can hear a bunch of baby backfires, when I give it alot of throttle and let off it sounds like I launched an artillery round out the back of the stupid car. My friend says it looks cool at night because flames shoot out of the exhaust pipes. I have only had the car a few months, but have put more work into it it than I really intended to!! Bet that has never been heard before! I have put a new EGR solenoid on it and have replaced the plugs, wires, cap, rotor and coil with Accel, Bluestreak, and Bosch parts, I have timed it like 5 times with an inductive light, I do have an exhaust leak that I would gladly kill anyone to finally fix after 3 hard and time consuming attempts, and I have tried multiple Rochester carbs. The carb that is on it came off my friends 84 HO TA and his didn't backfire with it on it so I figure that is not the problem. Someone help me before I commit insurance fraud!!!!!

-I do have a rich code. How do I fix it?

 

That sounds like the symptoms of a rich condition.

Do you have a working PCV valve? Did you adjust the MC solenoid when you swapped carbs? Adjust the TPS? What is your fuel pressure?

Any problems with those can cause a rich condition. Since oxygen sensors typically fail toward the lean end of the scale, if your's is reading rich, you're probably really rich.

 

Actually I did not adjust the TPS or MC, The Haynes is only for the 2bbl, could you be so kind as to tell me how to adjust them?
and I didn't think pressure mattered on a mechanical pump unless there was none (my own ignorance) I am learning all this stuff as I go, although I have basically rebuilt my other 83 it had no electronics on it, any help would be greatly appreciated!

 

.... oh. and your right on the mark, it is really rich, I have the gas mileage of an F-16!!

 

Any fuel pump that produces excessive pressure can cause fuel to overcome the inlet needle valve and flood the carb (and engine). Since this has apparently happened with nore than one carb on the same engine, I'd be looking at fuel pressure.

 

Someone help me before I commit insurance fraud!!!!!


Yea I wouldnt suggest that, heck they proley wouldnt give you enoght money to make 3-10 years seem worth it.

But I know what you mean, many a times Ive sat outside with a match and a tub of gas thinking of how easy it would be......

 

Check the alignment of the reluctor and magnet inside the distributor. Pull the cap, cut a slot in it so you can see the rotor at #1 post. Put it back together and pull the EST plug off the dist. Start the engine give it some RPM and aim a timing light at the slot...the rotor tip should be lined up with the post. If it's not, the magnet and reluctor are out of phase. This will cause backfiring like crazy...You can fix it yourself by slotting the holes that secure the magnet and line everything up...or...buy a new one...but check it for phasing.

 

This thread is older than dirt itself.

 

Yeah that was quite a few cars ago, thanks for the response but it ended up being the computer, the problem got alot worse and finally started showing a code so changed the compuer and it ran awesome . Wish I still had that car!!!