No start issue Im a little frustrated

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66dartgt

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Well, I am trying to start the 66. Finally.

It wont start due to a very weak spark at the plugs. I am talking pitifully weak. :???:

So, a friend has one of the ancient mopar service department electronic ignition system testers - we plugged it in.

Its telling me the following after running their tests:

ignition box is okay
coil is okay - shoots a hellatious spark out of the thing.
pickup is okay, checked the air gap too its at .008"

It says there is a problem in the primary wiring. Hmm. Using their flow chart it indicates problems with primary wiring, the ballast resistor, or the coil.

Okay - I checked the ballast with an ohm meter and it reads about 1.5 ohms, should be fine. This system is using a single ballast BTW.

I checked all the connections from the ignition switch for continuity to their respective end connections at the relay, ballast resistor etc, all check fine. So its not a bulkhead or wiring issue.

Installed a new ignition switch for the heck of it, because I thought it'd be fun (not).

That leaves the coil - But I already did their test and it throws a heck of an arc when energized.

I am stumped - Thoughts appreciated - My next guess will be to try a new coil ?

Either that or retrench to a point distributor to get it running temporarily. :angry6:

Help !
 
Just start with the basics. Turn the key on and see how much power your getting to the coil. I like to run mine at 8 but thats me. Next see how much your getting while someone cranks the motor over(should be close to 12). Don't over look the cap and the rotor. Carbon cracks are hard to see. Or better yet just check the spark while cranking from the coil itself if you have the right volts to the coil.
 
If it were me here is what i would do. get out the ohm meter and a chiltons manual it will tell you what the coil is supposed to read and also the resistance on the spark plug wires/always good to check them. if all that reads good then move on to the rotor button it could be bad and not sending enough spark to the plugs hope this helps
 
Okay thanks guys

I checked the voltage at the coil, and its 7.5 volts, on the positive connection with it on the run ignition switch position, I dont have a helper to test the start position right now.

I'll take a look into the cap rotor and wires tomorrow during the day, and the start position coil voltage.

Any other thoughts out there ?
 
you say "trying to start finally " so is this a fresh engine build ? If so maybe the distributor is dropped in 1/2 round wrong. Thn if its one that has sat a long time, fuel quality and plugs as mentioned before should be checked.
Folks go to a lot of trouble diagnosing a ballast resistor when really all thats needed is to take it off and look at the back side. Good luck
 
check spark form the coil to the distributor. you could have a bad coil wire.
 
Like rfb said, what does the spark look like right from the coil wire? I've seen rotors short out internally to the distributor shaft. Spark into the distributor, litlle or no spark out.
 
Thanks for the replies - Will check various items mentioned.

Motor is a fresh rebuild, with new plugs cap rotor, wires are old but look fine. The distributor is a known working piece as is the coil. distributor is in correctly, Engine almost starts in the present position just not enough spark energy, tried various positions on the dist timing as well - no dice.

Gas is fresh, new lines pump tank fliter and pickup. 6 - 7 gallons in the tank.

Ballast checks fine, swapped another one in that checks okay as well.

Good idea on checking the energy from the coil to dist.

If I get a chance I'll mess with it a little more today but if not -

Its gonna be a few days before I can futz with this again. I have a long weekend trip planned, leaving tonite.

I'd rather get this figured out but I have to make this trip first. So, I'll be back with further results later next week.

Darn it. :angry7:
 
A bad engine ground can cause problems too. Let us know what happens.

I used to live in the burbs of Chi-Town too. Good luck and have a nice trip.
 
Did you make sure your distributor is correctly orientated its easily installed 180 degrees out, sounds like everything else is in good shape.

Good luck
 
Back from my crosscountry adventure. 1660 miles in 2.5 days. ugh, was I beat last night, 3 beers to the wind and I was out.

Up this AM !

I have a ground wire junctioned to the block at the same point where the body is grounded to the block for the ignition box, and of course the block is connected directly to the neg terminal of the battery.

I'm pretty sure the dist is synched correctly, since its almost starting and when I put it in reversed it violently backfired a couple times.

Okay, I checked the resistance from the coil primary wire to the center connection in the dist cap. Its low - about 10,000 ohms. Ma mopar says per their service manual that when the resistance is less than 15,000 ohm to check for a faulty coil or coil to dist wire. Okay - I checked the wire its really low about 600 ohms. Not good. Checked another coil secondary wire I had laying around 11,000 ohms (should be okay). Gonna check some other coils I have laying around and compare their primary resistances to the output and see what looks right vs wrong.

I think I might have found it, but not holding my breath. I assume with low resistance that the coil or the wire is grounding partially causing the low energy spark ??

ram charger - where did you used to live ?

Back later with more results ---
 
I like to just take out the dist. and have everything hooked up and spin the dist in my hand and check for spark. Saves alot of time and eliminates alot of variables.
 
Well - after changing the spark plug wires, and coil wire and some more swearing it still does not run. spark at the plugs looks better.

Pulled a plug and its wet with gas, flooded obviously. Will buy a new set of plugs today and swap them out and Ive also been having trouble getting gas pumped into the carb, been drizzling gas in with a small cup. Gonna temporarily install a light duty electric fuel pump to eliminate that as an issue.

Pulling the dist while still wired up and spinning it is a very interesting idea. I will keep that one in mind.
 
almost starting sounds like its advanced past that #1 wire on the cap or youre off by one wire. pull #1 plug stuff a rag in it, disable ignition, bump the starter around till the rag pops out, rotate the crank around til timing marks line up and then pull the cap and see where the rotor points.
 
66dartgt said:
ram charger - where did you used to live ?
Click to expand...

North side (Cubs fan). Was born in Evanston and lived in Morton Grove and Des Plaines. Also lived in Chicago proper around Clark & Chase.

Engine ground is tight right? I know it sounds simple, but I've seen crazier stuff. It's hard to believe that the wires would be causing this problem. Some high perf wires have as little as 50 ohms per foot.

Double check your firing order and the direction of rotor raotation. Make sure you're on the compression stroke of the # 1 cyl. Check and make sure that the rotor is pointing at the # 1 plug wire at 10 degrees BTDC.

Let us know what else you find out. :smile:
 
I am pretty certain the plug wires are on correctly. Its a mopar cap, with the #1 position marked clearly with the rotation marked (clockwise as you look from the top), using 18436572 firing order. The cap has two sets of marks for big and small blocks - and Im using the small block marks.

At lunch time today, I checked the firing position on #1 and it lines up with the #1 tower at TDC, and rechecked the grounds, all tight.

Picked up some platinum plugs and a dinky electric fuel booster pump. I'll be laying on the cement floor of the garage tonite installing the pump. If it gets in tonite, I'll slap the plugs in it and recheck the tdc firing position of #1, and give it another shot.
 
66dartgt said:
The cap has two sets of marks for big and small blocks - and Im using the small block marks.
Click to expand...

Ok, that's what I was refering to. These caps fit both big and small blocks. I had a parts guy give me a BB cap and the direction of rotation has thrown me off before.
 
first off, platinum plugs are useless with a carb. you won't feel ****. secondly, if you gap platinums, throw them away. you just took off the platinum. i hope you plan on disconnecting the mechanical pump. you can rupture the diaphragm and gas can then enter the crankcase.
 
Or how to make yourself feel like a moron

Thanks to all for posting.

Its running ! :toothy7:

Did not install the electric pump, that'll be returned tomorrow $.

Pulled the old plugs and turned the motor over for 10-15 seconds to blow the cylinders out a little. Then stuck the new plugs in. Finally figured out where the damned bowl vents are on this carb. Not real obvious to me at least, this is an old aftermarket carter afb and does not have the brass vents on other carters Im familiar with. If you ever need to know where they are, they are semi rectangular holes on the towers for the step up pistons. Poured gas into the vents and tried again, repeated several times and some more futzing with the timing - it started.

Ran it for about 10 minutes at 2500 rpm, set the timing and then all hell broke loose with the cooling system - it ran up real high in the temp and I shut her down. It restarts fine but started getting hot all over again. Running straight water for now.

Checked the thermostat and it opens at 180F on the stove with a pot of water a thermometer and slow heating, so thats not the cooling issue. Imagine it needs the glycol to extend the boiling point to avoid boiling over.

At least the start issue is a done deal.

Next demon may be the cooling system, but that's another adventure.

thanks again for everyone's help, and patience.
 
Glycol doesn't extend boiling point. If the engine runs hotter than 180 with a 180 thermostat, you system is not able to expel the heat. Assuming your gauge is halfway accurate, start the engine cold and keep your hand on the upper radiator hose. You will know exactly when the thermostat opens, as the hose will get hot all at once. Look at the gauge, thats 180. Now take it for a drive at 35+ mph. If the temp keeps climbing, you have a radiator issue. Turn on the heater full blast, does this help? If so you need to take your radiator in to a radiator shop and have it rodded out. If you are running a slant 6 radiator with a V-8, it will probably heat up on you at idle no matter what. If you are boiling over, make sure the cap is new. If the system will not build pressure, it'll puke out coolant starting at 200 degrees.
 
Chief - thanks for the input - will try what you suggested once the car is drive-able. Needs a steering column, the brakes bled and the driveshaft shortened, oh and a drivers seat might help too -LOL.

The cooling system consists of a new copper/brass (recored) high efficiency 22inch radiator, the correct shroud, the matching 7 bladed fan with a new thermostatic clutch. The pump is standard issue, with the matching pulley set.
 
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