Not Firing #5 318

[bordin34]

The #5 cylinder on my 318 isnt firing, it just pumps air out of the exhaust, it is making a spark, the wires are good, the spark plug is good, and there isn't any play in the rocker arms. Any ideas?

[chargerbr549]

First of all I would do a compression check on that cylinder and if it checks good make sure wires 5 and 7 are not touching each other since they fire right after each other, you could be getting an inductive crossfire  between the wires. If that is ok pull the valve cover  and check to make sure the rockers are moving and not having a flat cam, possibility of a broken or weak valve spring or burned valves which of course should show up on the compression test, also spray around for possibly a vacuum leak somewhere, hope this helps.

Kevin

[bordin34]

I pushed on the valve springs and they seemed fine. The rocker toward the rear of the engine looked like it was opening a valve. I need to buy a compression gauge.

[mikepmcs]

hole in the piston?

[bordin34]

Its pumping air out of the exhuast so I think it has some compression. Maybe it just hates me.

[Challenger340]

Burnt exhaust valve on #5 cylinder ?

Compression test as stated.

[SUPERBEE123]

compresssion test if you have a tester if not and you have compressed air get both valve on #5 up and closed thight and pump compressed air into the sprak plug holes if loys of air comes out the exhauxt pipe burnt exhaust valve if lots of air comes out the carb. intake valve problem. if no air out of either vaccum leaks can cause a dead cylinder