bandy123

Man this SUCK A Big One!!! OK I have done everything I know to do. New Timing Set, Distributor, Coil, Coil Pickup, Distributor Cap rotor button, Plugs and wire. I have had it at 10 Different people and they all tell me something different. There 2 people telling me it the Cam.and people telling me its Valves. I don't Know what to do. Here is what it does. it Starts Good idles good. But when you give it gas it pops and backfires. Cam???????????? :sad: :sad: :sad: :sad: :sad: :mad :mad :mad :mad

Jason Staley

Might be the cam. I use to have a 6 cyl. Thunderbird that lost a lobe on its cam shaft. It didn't idle very good and I couldn't hardly give it any gas. One way to check it, is to remove the valve covers and rotate the cam and check the valve movement. Make sure all of your valve are going up & down. If you want to really check it good, buy a dial indicator and place it on top of each valve and make sure you get consistant readings between all your intake and all your exhaust.

Another thing, when I switched my spark plug wires last time, I got 2 crossed. Resulted in the car backfiring when I revved the engine. Idled just fine. Are you sure your wires are on right?? Good Luck. :seeya

bandy123

Yes it wired right I have went over it time and tim again.

ORVette

If you are still running your factory smog equipment, it could be causing the problem. Sometimes the diverter valve can cause this type of backfiring when it malfunctions. I do not know all the technical details, but I do know that I chased a backfire like yours on my '74 Monte Carlo. Tried everything you have tried to no avail. Then someone suggested the diverter valve on my air pump. Rather than try replacing it, I just removed all the smog equipment. Result-no more backfire! I don't know if complete removal is an option for you, but you may want to test your emmissions equipment and see if everything is functioning properly. I don't really have any idea how to test this stuff, hence the radical smog-ectomy on my Monte. Good luck!
Troy

BeachinVette

Check your carb too. My car does exactly the same thing. I think I am getting reburn of excess fuel in the headers. I am changing the carb out.


Bob

bandy123

No carbs TBI

mountainmotor

I have heard of the 82 motors with a flat cam and yes this will cause the problem you are experiencing but you should have some noise to go along with it.
Do you have lifter noise or is it possible the valves have been adjusted improperly?

bandy123

No it doesnt have any noise. The motor Starts and runs good Until you put it in gear. Then it pops out the tail pipe. I have replaced everthing But the cam and heads.

1979toy

Pull your spark plugs and valve covers. Rotate the engine and watch for rocker movement.

john's '81 mouse

Suggest you pull the spark plugs and perform a compression test. A cylinder with a flat camshaft lobe will have poor compression. Could you have a valve sticking? How about a broken valve spring? Agree you should pull valve covers and watch for rocker arm travel when performing compression test.