318 Intermittent Engine Issue

[markbob]

Hey all....

beautiful day in Chicago today.....took the 69 coronet out for a spin....

I have been driving it all summer, with no problems....but today was different....

I got a few blocks from the house, and the car started to shake, sputter, and I think it even belched out the carb (sounded like it anyway)

I limped it back to the house, and it kept dying on me anytime I tried drive the car forward into the garage...

I got under the hood, and checked all the connections, and such....couldn't find anything wrong.
I ran it 3 times today....once with no issue, and the other 2....same thing.

I swapped ballast resistors, (original with new) and it didn't seem to change anything.

The distributor is locked down tight, and the coil wires are also on tight....

any ideas where to look? I was thinking about changing the fuel filter first, and checking the fuel pump.....

thanks everyone!

MB

 

[mrsnicks]

Car only needs 3 things to run. Fuel, air and spark. Check for spark at the coil and at all the plug wires. Check for fuel to/in the carb. When I had a problem it was the ignition condensor.

 

[benno440]

sounds a bit like a fuel problem, check filter, maybe blocked jet etc.

 

[markbob]

Thx for help

Car won't start now
It kinda sputters but won't fire

Replaced fuel filter.... and rotor in distributor
Today I will get new cap.....Plenty of gas as plugs are wer
appears there is little or no spark
Will try a coil today

 

[markbob]

took some electrical readings....with key on....

when points open, battery voltage at drivers side of ballast resistor, around 8 on pax side.
8 on positive side of coil, and .21 on negative side.

when points closed, battery voltage all around.

cleaned and regapped plugs.

the engine is behaving like it did prior to having it rebuilt.
the timing gear was "slipping" on the nose of the crank, and therefore, you could not time the engine to save your life....and sometimes it would run, and sometimes, it would not.

compression test next, I guess...

any other thoughts?

thanks,



MB

 

[Funship32]

Hey Markbob, I'm just going to wade in here and give you a few things to think of. It sounds like you removed the cap to get to the points. Make sure the cap is intact at the notch at the base. I had a section of a cap break off at one point during reinstallation of a cap year ago. So while the cap was on, it wasn't aligned right and made the engine run like ka-ka. Also have seen the caps just go 'bad'. I know, I know, it's a weird thing to say but I had a 383 that would run like a champ and then one day out of the blue start misfiring and running like crap. Ended up replacing the cap and voila- ran like a champ and that happened to me 2X's over the years. Also have a dodge truck that would just die on me for no apparent reason. Replaced the cap and that problem went away. So I'd do a new cap, rotor and see how it goes from there.

 

[coloradodave]

Instead of throwing parts at a problem and hoping you find it, invest in a multimeter. Continuity from the plug wire receptacles on the top of the distributor cap to the rotor contacts inside the cap is easy to test if you have a meter. Same with the coil, ballast and distributor parts. Factory service manual has all the values. Could save lots of money. I posted a good trouble shooting guide on here a while back. I'll see if I can find it.

- - - Updated - - -

Whoops, I see you DO have a meter. Mea Culpa

Put the motor on TDC compression stroke and see where the rotor's pointing. Also, since you have a multimeter, do the checks outlined in the factory service manual for all the ignition components. Maybe this will help:

http://www.moparaction.com/tech/archive/roadside.html

Good luck.

 

[markbob]

Thanks for the link.....

I read it over, and have done the following......

The engine is getting plenty of gas....no problems there.

I motored engine to where timing mark on dampener was near tdc.
I also watched the rotor in the distributor, and listened to the motor crank.....the rotor turns, and the motor sounds just like it did before.

I checked the spark from the coil....nice even spark to the valve cover (ground)

I checked the voltage to the + side of the coil....it appeared a bit low (around 5). I swapped ballast resistors and rechecked.....it was now around 9.

I seemed to be running out of ideas, and thinking it may be the carb.
I decided to jump the battery to the + side of the coil. I cranked the engine and it seemed to hesitate at first, and then it caught and started up.

It ran for a while, and then it appears to have cleared up....starts and runs fine.
I rehooked up the original ballast resistor, since it appeared the second one was not dropping the voltage like it should. The motor started right up and ran fine, but then when my son took it for a spin around the block, it died again.

I let it sit for a while, and it started right up. ran fine.
I tried to pull it in the garage, and now it doesn't start. I tried it again, and now it's starting fine.

It appears jumping the + side of the coil to the battery got the engine running again.....

any other thoughts?


thanks again,

MB

 

[markbob]

went out to garage....engine cool....

attempted to start....it fired immediately, ran for around 30 seconds, and then quit.

I attempted restarts, and the engine won't start....it fires, and sputters just like before.

I checked the voltage on the + side of coil....under 5v.

I changed out ballast resistors, and the engine still won't start....same sputter, and won't catch.

I checked wiring diagram, and the power comes from the start switch through bulkhead connector to the + side of coil.....shouldn't I have battery voltage there....not 5 or 9?

will try to jump battery to + side of coil tomorrow....

am thinking I don't have a good connection through bulkhead connector, or am loosing volts somewhere else.

will let you know..

MB

 

[RRcrazy]

Had a similar experience with my 70 RR it was really scary almost like you lost the motor hesitating surging really bad while running it came up all of a sudden in a previously good running car., I thought I lost timing it was so bad parked it and it wouldnt start. I did all the same checks as you did and was ready to drain my tank when my wife said didnt you buy the wire thing? I changed the wiring harness under the dash over last winter but didnt change the engine harness yet. So I pulled the old engine harness out and put the new one in and problem solved. It must have been shorting out the engine and killing it. So before you go nuts look at your harness maybe time to buy a new engine harness its not too expensive. Good Luck.

 

[markbob]

Thx to all

It was the condenser!

Figures

 

[coloradodave]

Great call mrsnicks! Don't you just love it when you nail it?