Stephen Chen

Hi all,

1967 Plymouth Fury III 383 engine.

It was running fine, until one day while driving, a loud backfire, engine died.
since then, replaced:
coil, fuel filter, fuel pump, distributor, spark plugs, timing chain. all band new.

rotor points to #1 cylinder on compression stroke at TDC
timing mark lines up with damper
have sparks, have fuel, fully charged battery.
Compression:
cylinder 1: 100 psi
cylinder 2: 50 psi
cylinder 3: 95 psi
cylinder 4: 105 psi
cylinder 5: 0 psi
cylinder 6: 100 psi
cylinder 7: unknown, can't get to it.
cylinder 8: 110 psi.

cranks and cranks, but won't start.

please help.

Iowan

Do have spark or 12V at the coil?

Stephen Chen

at spark plugs

fivepoint

Have you looked into why you have no compression on #5? Take the valve covers off and see if the rockers are moving as they should when you crank the motor.

Stephen Chen

Hi, I just re-tested compression on #5, it is 120.

Compression:
cylinder 1: 100 psi
cylinder 2: 50 psi
cylinder 3: 95 psi
cylinder 4: 105 psi
cylinder 5: 120 psi
cylinder 6: 100 psi
cylinder 7: unknown, can't get to it.
cylinder 8: 110 psi.

what else could be the culprit?

RacerHog

My Guess from your description >>>>> Timing Chain Jumped Time.....

Stephen Chen

new timing chain.
when I installed it, I made sure dots on gears are lined up: top gear at 6 o'clock, bottom gear at 12 o'clock.
also, right now, rotor points at #1 cylinder when 1st cylinder is TDC on compression stroke.

RacerHog

Hook 12Volts from the battery to the key side of the ballast and see if it starts?

Stephen Chen

how exact do i do that?

RacerHog

With a jumper wire and 2 alligator clips....
If this is above you skill level. I would recommend seeking help so you do not damage any other component when testing.

Stephen Chen

Update.
I was so focused on the timing chain, distributor, overlooked the carburetor, until a friend of mine came over, and discovered that the choke plate was jammed closed.
After freeing the choke plate, it WANTED to start.... so close..... I can feel it, it so wants to start. I think I fueled the cylinders by cranking it so much. gona give it a rest then try again.

I think we are onto something here.

RacerHog

Pull all the plugs and crank it over to push all the fuel out... Then start over.... Good luck..