the mystery continues ,, have you looked at the diaphragm in the vac advance could have a rip or a pinhole ,, you said you had a electric fuel pump in line did you remove the pump

 

checked vacuum advance a few months back with vacuum and it seems to be moving ok and holds the vacuum until its released.bypassed the electric last week but no change.

 

Okay I'm into another situation which is not good. I had the air cleaner off today and was cranking the car to start . after numerous tries suddenly the car backfired through the carb. Its sounded like a M 80 went off! I have tried to start the car after that and all I can see is smoke or atomized fuel coming up out of the carb and if I continue to crank it it will pop. any ideas whats going on ? also due the the severity of the initial explosion is it possible that my Rochester carb was damaged??

 

IMHO, you have some kind of ignition/timing issue. You DON'T get backfires out of a carb due to fuel delivery issues.

 

Carb should be ok.

 

do you still have points in the car

 

Yes I checked the points, the distributor cap and rotor last night. I swapped out the coil for an older one I had thinking that might be the issue thats when all these new problems started. I put back on the newer coil but the car still wont start and is popping etc. through the carb. i was second guessing the way I put the wires on the coil but I'm pretty sure negative goes to the distributor.


issue

 

the wires go on 18436572,, did you mark #1 when you took it off

 

sounds like timing, either the wiring got messed up or your timing chain is jumping teeth. Get someone to spin the motor while you check the timing.

 

Not sure how that works when the motors not running. Can you still check it for correct timing just by cranking the motor?

 

yeah i must agree the wires are messed up i dont think your timing chain is skipping but it could be worn how many miles on the car?? if the chain is worn you would have a idle issues .. your rpms would be all over the place ,, you can check the chain tension without taking the motor apart

 

Motor was rebuilt many years ago maybe 60 K since then. Last run out the car was running lousy so I'm not sure if it finally got to the point of this problem or its something I did started it all but I did recheck everything tonight in the distributor as well as the coil connections and all seems good. not sure how to trouble shoot it from here.

 

Ok I pulled # 1 plug and checked rotor position at TDC on compression stroke. The rotor is pointing about 180@ off between #5 & 6 distributor cap wires. Rechecked to make sure I was not on exhaust stroke. Obviously somethings screwed up. Is re positioning the distributor to TDC appropriate at this point?

A little history: The car was my brothers handed down to his son who had it up on block for about 20 years. 2 years ago I had the car shipped to me. I did all the basic procedures for preparing to start a motor that was stored for awhile. I just could not get the car to run. after weeks of trying I found the rotor pointing 180 degrees off of the #1 cylinder at TDC. I am still puzzled about how the rotor ever got that far off because I know the car was operating before it went into storage. I pulled the distributor and set the rotor to the proper position. I have run the car since but lately have been having intermittent hesitating, stalling, unstable idle speeds and hard cold starts which had been attributed to possible carb / fuel delivery problems. The weird thing is to see the rotor back in the same position it was in 2 years ago when the car wouldn't run pointing 180 degrees off. Dont know if there is any significance to these events but its very weird.

 

is your timing mark lined up at 0* on the front of the motor? Are you absolutely sure it on the compression stroke. it is most likely the exhaust stroke. I doubt that it jumped that many teeth. If the mark is on you probably didn't jump

 

I doubted these results too so i have checked it cranking with my thumb over the plug hole and the rechecked by inserting a vacuum gauge /fuel pressure gauge plug into the # 1 spark plug hole cranked the engine and it blew out the plug at the same location about 180@ off, rotor pointing between #5 & 6 distributor cap wires. The timing mark showed about 12 degrees advanced from 0. I have not pulled the valve cover off yet to view the # 1 valves as another confirmation.

 

. If its not running you can pull it and rotate it. If it does start then I would shut it down and pull the water pump and replace the chain. Jumping exactly 180* would be some kind of luck

 

I wouldn't bother pulling the valve covers at this point. I would just pull the distributor and restab it at number 1 and try firing it up and see what happens. I suspect it will run. How well? Don't know.

 

Pulled dist and rotated it to " 1 position on compression stroke cylinder one TDC verified with valve cover off . car would not start, moved it one more notch clockwise toward plug wire # 8 and was able to get car to start. Timed motor ,idling okay took it out of driveway and car stalled out 1 block away had to push it home. After playing with dist positioning I was again able to get car started at the #8 position. I re timed the engine. It idled okay for approx 3 minutes then the idle suddenly started to climb to 1000+ RPM as it did when this problem first started. I have also noticed no vacuum from the dist vacuum advance hose connected to the carb (I was able to blow into it to make sure the carb vacuum outlet was not blocked). Manifold vacuum was running at 7 or 8. timing marks held steady during timing no jumping as you would find with loose timing chain. Cant tell for sure if harmonic balancer ever slipped but it looks okay.

 

if it was 180* out then it either jumped the chain, the gear on the distributer has broken the pin and is rotating, the gear on the cam is bad and the distributer cant keep timing, or something else that is related to the distributer and cam. I would take off the timing chain and if thats not it pull the cam. Whatever it is, it isnt simple and its not going to go away. Keep us updated

 

You started out with a restriction on the suction side of the fuel pumps. Looks like now you have created another situation to correct before you can identify where the restriction in the fuel system is located. Slow down and work smart.