O)dd Dwell Meter Behavior Question
 

I have 2 dwell meters-1 analog and 1 digital. My car has points and CDI.

I first set the gap with a feeler gauge.

When I connect the red wire of the digital one to the side connector of the distributor and the black to the fan shroud nut I always get 60 degrees, whether the engine is cranking or not. The black wire from the coil is disconnected on the side.

When I also connect the thin wire on the side the reading drops down to 0.

I can see the dist spinning and the gap opening and closing.

When I follow the same procedures with the analog gauge I always get 60 degrees.

I've done this many times over the years with this car and never had this problem. I don't understand why I should get 2 different readings (60 v 0) from the tests, and I don't understand why I'm getting a reading of 0 or 60, rather than something that varies with different gap settings I do.

Can someone let me know what could be wrong?

New points in and set to correct gap using feeler gauge.

Still at a loss to explain:

1. Why analog gauge still gives 60 degree reading in both scenarios

2. Why digital gauge still reads 60 when thin wire is not connected and 0 when it is

3. Why engine will now not start at all.

4. Why, when I've been changing points for nearly 50 years in my cars, I'm having this problem now

Going back to previous points set and restart the procedure

Hi Paul,

Doesn't the red one clip to the little negative post on the coil?

I have never set points in a Porsche though.

Thanks Bob.

I think the red one goes to the contact on the side of the distributor on CDI cars. Apparently hooking up to the coil can burn out your CDI box and/or your dwell meter. If I had a Kettering style system, I think the wire would go on the coil.

At least this is how I have it diagrammed in my shop notes and how I think I've always done it. I'm wondering if my aged brain (72) is playing tricks on me and I'm doing something different. I have an old videotape of the procedure that I can consult if I can get my tape machine working.

Yep. Forgot about the warning sticker on the coil.

Let me see if I can find something for you to view.

I see your posts from 2007 with Loren and others. You know way more about it than me.

60 degrees could indicate the points are never opening since the lobes are 60 degrees apart on a 6 cyl.

Why though, assuming the meter is correct and the points are opening?

Gotta have a fresh battery or readings will be off. Black ground and red clipped to a skinny screwdriver to touch the distributor terminal should work.

Thanks John. New Odyssey.

Success!

Here's what I found:

I switched points back to the set that was in the car. They looked perfectly fine. They apparently had just gone way out of adjustment. I had my saintly wife crank the engine with the fuel pump relay out and used the 2 screwdriver method ( 1 to pry against the nibs on the points and 1 to tighten) to set the gap. I got 35 on my old analog meter and locked it down. Engine fired up right away. I then hooked up my new digital meter and also got 35 with the engine running. Nice to know the 2 meters agree.

I hooked up a new wire to the side of the distributor and connected the distributor wire and the red meter connection to it. Otherwise I would have needed 3 hands and 3 screwdrivers!

So it looks like I just wasn't able to get the gap set well enough via the feeler gauge. I either was too large, yielding the 0 reading, or too small, giving the 60 reading. I'm surprised the readings were that extreme, but that's what I got. The amount of gap variance is, obviously, very small.

For me, the key was to get the screwdrivers located just right and then not be afraid to keep the engine cranking long enough to make the adjustment. Just took a little time and patience. The actual cranking time was actually very little, maybe only 30 seconds or so.

I'm disappointed to see that the points went that far out of adjustment in only about 1500 miles. This may speak to the current quality of these things, which probably won't improve.

I'm nearly out of my cache of new points so I think I'll go with the Pertronix 91867A and not have to go through this again.

Thanks again to all who replied.

Thanks for posting closure on this. So many folks don't.

The battery I was referring to would be in the dwell meter.

LOL! Of course. New digi meter and new battery. Good to know for the future.
BTW my analog meter doesn't have a battery.

Mine does. An old Fox Valley. I like analog meters and timing lights. A lot less jumping around.