67 Lemans 326 Intermittently Missing

LeMans326

LeMans326

New member
Joined
Dec 7, 2017
Messages
11
Reaction score
0
Points
0
Location
Flint, MI
I purchased this car about a year ago. When I bought it it had been running rich, and the exhaust was sooty (would leave black marks on the ground when first starting it), and I've been trying to get everything back into good shape. Earlier this year the car started randomly missing after getting warmed up. I assumed the plugs were probably in bad shape so I pulled them and replaced them with new Delcos. The miss went away and the car drove great, however during a rolling cruise a few weeks ago it started missing again. Car was not overheating or anything, and it didnt get any better once I headed home. By the time I pulled in the driveway it was missing so badly that it would stall at idle. Over the past couple weeks, I have checked the following:

Replaced Coil
Replaced Voltage Regulator
Checked and regaped Points
Visual inspection on ground straps/wiring
Visually inspected plug wires
Visually inspected cap/rotor
Checked fuses.

The car cranks strong, and occasionally when it's cold it will run pretty good, but it always misses again once it warms up.

I have a dwell meter/DC volts meter I had hooked up. And I switched it over to Volts while it was hooked to the coil

It read 6 volts at key on/engine off
And would jump to around 12 volts when cranking, and then fall immediately to 3 or 4 volts and stay there when the engine was running.

This car has been a "learn as I go" type of project, and I appreciate in advance any tips or insight!
 
You state you have a dwell meter, did you set the dwell to 30 degress and then set the timing with vacuum advance disconnected?
when you reconnect the vacuum advance to a vacuum souce does the timing advance?
Assuming the points look good, not burnt, did you try replacing the points condenser?
Did you use your meter set it for ohms and measure the resistance on each wire, no more than 1k per foot of wire.
What number plug did you install and did you gap them to .035?
Hve you checked the voltage readings you get on another car to make sure the meter is reading correctly. You should not be seeing 3 or 4 volts at any time ?
with the engine running is the alternator putting out 13.5 to 14.5 volts?
which carburetor is on the car, 2bbl or 4bbl rochester?
 
I think 1967 was the last year they used the Carter AFB for the 4BBL carb. It wasn't until 1968 when they started using the Rochester for the 4BBL carb.
 
The car has a 2bbl carb.

I did verify the dwell meter/volt meter are both accurate.

Dwell is at 30°

Timing is set correctly, and vaccuum advance is working

Plugs are gapped correctly

I have not replaced the condenser yet, though I did replace the points just to be sure and there was no difference.

I am still reading 3 volts on the coil when engine is running. I'm starting to wonder if the ignition switch may be bad. I'm going to run a bypass wire from the battery to the coil and see if everything smooths out.
______________________________
 
with the engine running and the voltmeter attached to the battery do you get 13.5 to 14.5 volts?
The coil positive terminal has a dual wire, one comes from the starter and supplies full battery voltage when cranking. The other is a resistance wire coming from the switch and lowers the voltage to about 9 volts. Does anything look suspicious about that dual wire where it connects to the positive terminal of the coil?
 
As said I would check for the 8 to 9 volts to the coil with the engine running, also if you have not replaced the plug wires I would, in my experience they can only be counted on to perform well for about 5-7 years. They may look fine but can break down internally.
 
I appreciate everyone's help!

It's fixed! Turns out it was the condenser for the points that was bad. Replaced it and it's never run better!
______________________________
 
excellent news
 
That's Interesting, I always replaced the Condenser when changing the points as it usually came with the Kit, but I actually never had one go bad. Thanks for the update.
 
You must log in or register to reply here.

Share this page

Back
Top