The Stovebolt Site Forums The Shop Area The Electrical Bay problem with distributor

This is a long story, so please bear with me. I developed a hard miss, and after pulling plug wires determined it was the number 5 cylinder. All the other cylinders were doing ok, so I thought it must be either the plug, or the plug wire. I changed both, no luck. Same story. My next move was a new distributor cap. Same story. No change. In fiddling around with the distributor I discovered the wire from the condenser to the points seemed a little loose, so I tightened that. The problem only got worse. Now the truck won't start at all.

I used a multi meter, and I have continuity from the point side of the coil through the closed points to the stem the rotor sits on. When I put the rotor on I no longer get a reading from the top of the rotor. Shouldn't I get one?

Using a test light, with the ignition switch turned on, I get a light from the battery side of the coil, but nothing from the other side. Should there be current there also?

Before the truck quit completely, I could put a timing light on any of the plug wires except the number 5 one, and I would get a flash. The number 5 was completely dead.

As you can see I am just replacing parts, in the hope something works. My next move is to replace the rotor and condenser. The really aggravating part about this is that all these parts are new. The truck just had a complete do over, and everything was replaced. I did use the old distributor. Does anyone have any suggestions? I despise working on the electrical system. I don't understand electricity, and there are no moving parts to look at, so I'm usually a total idiot. Help.

I'm no expert on points ignition, but is the condensor inside the distributor? if it is and you tightened a screw you mave have adjusted the points so they are always open. this would create a no start condition. if you always have no spark on #5 with new cap and wire, sounds like you might have a worn lobe on the distributor shaft.you should be able to see one shorter than the rest. I'm going to go down to the shop tomorrow and look at my ignition and if i find a good likely reason for only one cyl down, i'll post again tomorrow or sunday.

Allen,

I think you might be confusing yourself. Although your meter can check the primary side of the ignition, points etc it is of no value on the secondary side. Without doing anymore checking, I would replace the points and condenser and rotor. Take your time and set the points perfectly. Fire it up and see what happens.

The valve train can't be ruled out. If the R&R of the ignition components doesn't cure your miss, you might end up removing the valve cover for a look. A simple compression check before pulling the valve cover might not be a bad idea.

Sometimes the checks with meters and timing lights only confuse the issue. When you have the distributor cap off, wiggle the distributor cam and make sure it isn't doing the hula. Good luck.

Stuart

no the stem is a ground the rotor current just goes from the center button to the outside contact for the cap your points are shorted or durty just get new points and condenser install it right that will take care of it

if point gap is set and #5 has no fire and cap is good check point opening and closing when dist is at #5 if dist cam lobe is gone point willnot open so no fire on that cyl...doc

Sometimes when you tighten the term in the dist you turn the wire terms. & they short to the dist. plate. Like the previous bolters said you may have a worn lobe or a bent shaft causing no spark to #5. Try setting the point gap wider.

Thanks fellows. I have been thinking about this since I sent my request, and I think you are right about the points being grounded. I could at least get it to run on 5 cylinders until I fiddled with the connection from the coil to the points. That would seem to point to there being a bad connection there. That wouldn't explain why only cylinder 5 wasn't firing. If as you suggested, I have a worn lobe for number 5 does this mean a new distributor, or is it repairable. I am going to work on it this afternoon, and will let you know what happens.
Again, thanks for the replies. This is absoutely the greatest site. I don't know what I would have done without it when I had the truck torn apart and was trying to get it back to gether. Allen

Allen,

In my very humble opinion, if you find only one lobe of your distributor cam worn so as not to operate the points on #5, I will personally fly to Northern Virginia and paint your house two coats of the color of your choice. Take your time and let me know what color suits your fancy.

Stuart

Maybe he want,s it painted chartroose. It,s true one lobe would not wear down that much but a combination of lobe wear, bent shaft,& point gap too small will cause a condition like Baker has. You would look for a bad valve or valve train but he says thr timeing light will not flash on that cyl. it indicates no spark or shorted spark. It,s a new plug but possibly the gap has been mashed shut from mishandleing.

Thanks fellows: Problem solved. It was right in front of me all the time, and I didn't see it. The screw holding the points down either had not been tightened properly, or it had worked loose. Either way the points had moved until they were not opening at all in the end. I reset them to a snug .20, and it's now running like a well oiled watch, at least for the time being. A friend and I rebuilt the motor. Neither of us had ever done anything like this before, so I keep holding my breath waiting for something to fall off or stick or something. I appreciate the help. I probably would still be looking if you hadn't pointed me in the direction of the points. Allen

Allen,


Does this mean I'm off the hook on the chartreuse paint job?

Stuart

Atomarc, probably you are off the hook. It's kind of a shame. I would drive over to Virginia OOPS West Virginia to see a properly painted metallic house. Sorta like ths aluminum cups we had back in the 60s. And yes the charteuse was my favorite!! Jimmie D.