'72 Brave, cranks, mostly won't start

[loothi]

Oh - hello all.


I just wanted to run this by all of you. Our (my husband and I) '72 Winnie recently started having problems on our epic 6k miles (so far) of work-travel across the USA. Whilst we were transversing Death Valley no less!


Anyway, we've had increased difficulty starting, loss of power, backfires, and random stalls at slow speeds/uphill .. we tried to fix it with a mechanic to little avail.. and it left us crawling out of Death Valley ending in a tow out of a canyon campground. 


So, and please forgive me but everyone has to start somewhere, so we are attempting to at least diagnose our problems solo. We also enjoy the challenge - when not feeling shamed for not having a purring vintage RV.


Following the "spark, gas, compression" triumvirate we've tried a new fuel pump and filter, and adjustments to the carburetor. No joy - so we're investigation spark issues next. Our battery(s) are very powerful, and the starter sounds strong. We're getting a tester to see if all out spark plugs are firing and intending to trace any problems back. I've got a tonne of relevant manuals (including the Dodge one from the store here) and have examined youtube.. but just wanted to see what order of troubleshooting you more experienced pilots might recommend?


We've some tools and will next invest in one of those nifty flashy light things you attach to spark plugs. It's most likely an original 318-3 (it's previous owner couldn't confirm if it might have been upgraded to a 360) with about 85k miles.


Any links or guidance that are appropriate?


Thanks
~loothi

[LJ-TJ]

Ok! I'm by no stretch of the imagination am an expert. At one time I had a similar situation. It was the coil. As the coil heated up it would break down. The engine would start to miss, then start to loose power, backfire and eventually quit. It had me buffaloed because it was a brand new coil, I mean brand new. I wish I could say I trouble shot the problem I don't know why I changed out the coil but I got so fed up said  put another coil on and away we went. For the price of a new coil it might be worth a shot. After that my talents just goes with changing out the Voltage Regulator, Ballast Resistor and Electronic Ignition. i??

[Rickf1985]

Since you have already checked out the fuel system I would also lean toward the coil, the symptoms you give sound like a bad coil. Especially if it starts out running good when you first start and then gets worse as you go along. Once it cools down it will run good again until the coil heats up. this heating period could be a minute or an hour or seconds. I have seen electronic control modules do this but very rarely. The ballast resistor will be good or bad, ie; it will run or not run. Hence, you should always carry a spare ballast resistor, they are prone to failure.
Unfortunately it is tough to actually catch a coil that is going bad in a test, you can ohm out the connections but by the time you get to it and get the wires off it may have cooled off enough to show good on a test even if it is bad while running. This is one of those things where if the diagnosis points in that direction it is best to just replace it since they are not that expensive.

[DaveVA78Chieftain]

Dodge did not start using electronic ignition until 1973 so this should be a points based distributor.
Have you:
Replaced the points and condenser?
Are the points adjusted to 0.015 +/- 0.002? (.014 - 0.019)
Rotor and distributor cap in good shape?
Replaced Ballast Resistor? Known Dodge weak point. Points based system uses a 2 terminal resistor, not the 4 terminal electronic distributor version.
Distributor Vacuum advance can and vacuum hose OK?  Will cause poor running if rubber diaphragm in advance can is broken
Distributor Centrifugal Advance mechanism working OK?
Timing set close to TDC?
Coil wired correctly?
Have you checked for a stretched timing chain?

Both points based and electronic distributor info shown here: http://dave78chieftain.com/Dodge_Electron03.html

[RickHolz]

I put a new electronic distributor with built in coil into my 318 and it was easy and made a very big difference cost on eBay new about $78.00

[RickHolz]

318 360 SB Mopar HEI Ignition Conversion Distributor Dodge Plymouth 340 273 on eBay simple to install



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[loothi]

Thanks all, and brilliant checklist DaveVA78Chieftain! It was dodgy points, they've been replaced with a new condenser. She's running like a champ again. Also I have inadvertently learnt lots about other bits of the engine in order to get to this stage. Fun and humbling.


RickHolz, if you still need me to check, drop me a direct msg - I have no idea where the brake distribution block valve is, but happy to find out if it helps.


THANKS 

[DaveVA78Chieftain]

Glad I could help - Happy Travels