backfire through carb ,smoking 73 chrysler newyorker 7.2 440

[sidsnot]

hi i have 73 chrysler newyorker 7.2 440,went to car show few weeks ago ran fine ,went to go to show last week car would not start ,i was parked on a slope ,thought fuel low and run to back of tank,so got a gallon and put it in still would not start so it tipped some in carb and away it went.got to show car popped a few times and was told it was smoking .time to come home from show hard to start popping from carb,got it going and drove home ,popped a few times.so i looked for fuel filter and found 2 pipes was split so replaced them and filter ,thought that must have been the problem ,but still the same smoking backfiring through carb .so had a look at distributor cap and found rotor worn bad ,so changed rotor and cap,changed ht leads ,ballast resister. spark plugs ,can get car to run but smoking go to drive away and just pops and bangs out of carb.did compression test on number 1 155 psi 2 175 ,3 165.5 170,6 165 ,4 160, .any help thanks dave in uk could not get guage on 7 and 8 cylinders.

 

[Davea Lux]

Sounds like your timing chain might be in the process of failing. Jack the car up enough so that you can get under it. Put a breaker bar with a socket on the big nut that holds the harmonic balance on.
Next remove the distributor cap and rotate the crankshaft with the breaker bar until you reach TDC
Have a helper move the crank shaft back and forth until the rotor on the distributor starts to move. Do this several times back and forth.
If you observe that it took more than 10-12 degress of crankshaft rotation to move the rotor, you have a bad timing chain that needs to be replaced.

Dave

 

[david hill]

Sounds like your timing chain might be in the process of failing. Jack the car up enough so that you can get under it. Put a breaker bar with a socket on the big nut that holds the harmonic balance on.
Next remove the distributor cap and rotate the crankshaft with the breaker bar until you reach TDC
Have a helper move the crank shaft back and forth until the rotor on the distributor starts to move. Do this several times back and forth.
If you observe that it took more than 10-12 degress of crankshaft rotation to move the rotor, you have a bad timing chain that needs to be replaced.

Dave

 

[david hill]

hi i have 73 chrysler newyorker 7.2 440,went to car show few weeks ago ran fine ,went to go to show last week car would not start ,i was parked on a slope ,thought fuel low and run to back of tank,so got a gallon and put it in still would not start so it tipped some in carb and away it went.got to show car popped a few times and was told it was smoking .time to come home from show hard to start popping from carb,got it going and drove home ,popped a few times.so i looked for fuel filter and found 2 pipes was split so replaced them and filter ,thought that must have been the problem ,but still the same smoking backfiring through carb .so had a look at distributor cap and found rotor worn bad ,so changed rotor and cap,changed ht leads ,ballast resister. spark plugs ,can get car to run but smoking go to drive away and just pops and bangs out of carb.did compression test on number 1 155 psi 2 175 ,3 165.5 170,6 165 ,4 160, .any help thanks dave in uk could not get guage on 7 and 8 cylinders.

 

[Yatzee]

hi i have 73 chrysler newyorker 7.2 440,went to car show few weeks ago ran fine ,went to go to show last week car would not start ,i was parked on a slope ,thought fuel low and run to back of tank,so got a gallon and put it in still would not start so it tipped some in carb and away it went.got to show car popped a few times and was told it was smoking .time to come home from show hard to start popping from carb,got it going and drove home ,popped a few times.so i looked for fuel filter and found 2 pipes was split so replaced them and filter ,thought that must have been the problem ,but still the same smoking backfiring through carb .so had a look at distributor cap and found rotor worn bad ,so changed rotor and cap,changed ht leads ,ballast resister. spark plugs ,can get car to run but smoking go to drive away and just pops and bangs out of carb.did compression test on number 1 155 psi 2 175 ,3 165.5 170,6 165 ,4 160, .any help thanks dave in uk could not get guage on 7 and 8 cylinders.

This is usually the case when a valve is not completely closed during ignition on one or more cylinders. As stated above, the timing chain and gears are toast, your distributor timing is off, or you have a sticking valve, broken valve spring or collapsed lifter. None of which are fun to fix. And don't discount an issue with the internals of the distributor itself or it's drive gear.

 

[david hill]

If the timing chain passes the check for slack as indicated by Davea Lux. My next thoughts go to ignition coil. Easy check is to hold the ignition coil lead from the dist. cap about .25 inch from the engine and have someone crank the engine over. You should see a very strong spark appear. If weak or none present, the ignition coil is bad. If good reinstall coil lead and repeat at any spark plug wire. No spark means possible failed new parts. PM me with results.

 

[65sporty]

The compression no's you did get look ok, do you have a timing light? If you do Dave's test it will show you if the chain is loose but if you have a timing light and check the timing and it's way off it will confirm the chain jumped.