timing sensor voltage

[rgoot01]

If your battery retains voltage, the coil should not drop like that

Yes sir, The battery does retain voltage.

Now I need to figure out what coil. J&P has two listed for my '89 but the oem# they replace are two different coil numbers. One replaces 31620-88 and the other replaces 31614-83. I just need to know which one I need or will both work?

 

[Jack Klarich]

Yes sir, The battery does retain voltage.

Now I need to figure out what coil. J&P has two listed for my '89 but the oem# they replace are two different coil numbers. One replaces 31620-88 and the other replaces 31614-83. I just need to know which one I need or will both work?

12 volts 3 ohms, both should work

 

[rgoot01]

12 volts 3 ohms, both should work

Jack, Thank you very much for your help. Thank you everyone else in helping with problem. I will order my coil and hopefully be on the road again next week.

 

[Hoople]

I will order my coil and hopefully be on the road again next week.

I tested as you suggested the battery reads 12.35 volts.

Now clip your voltmeter between the positive coil terminal and to frame ground.

If you performed the tests exactly as described, and the battery maintained appox 12.35 volts during the entire test time,, it's probably NOT the coil.

 

[rgoot01]

If you performed the tests exactly as described, and the battery maintained appox 12.35 volts during the entire test time,, it's probably NOT the coil.

I haven't ordered anything yet. What could it be?

 

[Hoople]

What could it be?

What color are the wires going to the primary side of the coil. Which wire did you have your voltmeter on during the voltage drop test. Are there any terminal markings on the coil (Batt,,+,, etc). If so, what color wire is on which terminal marking.

 

[rgoot01]

What color are the wires going to the primary side of the coil. Which wire did you have your voltmeter on during the voltage drop test. Are there any terminal markings on the coil (Batt,,+,, etc). If so, what color wire is on which terminal marking.

There are no markings on the coil (bat,+,-). With the new harness (32408-90) for the module (32405-91A), I have 2 pink wires on one side going to tach and module,and 2 white wires on the other side going to the starter switch and the module. I tested both sides of the coil during the drop test, the side with the white wires stayed constant, the side with the pink wires is where I experienced the voltage drop.

 

[Hoople]

There are no markings on the coil (bat,+,-). With the new harness (32408-90) for the module (32405-91A), I have 2 pink wires on one side going to tach and module,and 2 white wires on the other side going to the starter switch and the module. I tested both sides of the coil during the drop test, the side with the white wires stayed constant, the side with the pink wires is where I experienced the voltage drop.

The white wires are the ones you were suppose to test. I would expect to see a drop on the pink wires, so disregard the pink side readings.

While the meter was on the white wires and frame ground, what was the voltage reading as you turned the engine by hand. It should always stay near battery voltage.

Is the manual your using a Genuine HD manual. You said your measured reference was 12 volts but the manual says it should be 5.0 volts. I am not convinced if your reference voltage for the hall sensor is +5 or +12 volts because the module (32405-91A) your now using was designed in 1991 and I wonder if it now uses a 12 volt reference.
Go back and measure your reference voltage.

You say the spark looks weak. You may want to test it. There are two high tension wires coming out of the coil. Using an alligator clip jumper wire, jumper 1 high tension wire to frame ground. Take an old spark plug and gap it to .100" or just remove the adjustable electrode. Connect the other high tension wire of the coil to this test plug. Connect the threaded portion of the plug to frame ground. Crank the engine using the starter and see what the spark looks like. It should be able to jump that free air gap.

 

[rgoot01]

While the meter was on the white wires and frame ground, what was the voltage reading as you turned the engine by hand. It should always stay near battery voltage.

Is the manual your using a Genuine HD manual. You said your measured reference was 12 volts but the manual says it should be 5.0 volts. I am not convinced if your reference voltage for the hall sensor is +5 or +12 volts because the module (32405-91A) your now using was designed in 1991 and I wonder if it now uses a 12 volt reference.
Go back and measure your reference voltage.

You say the spark looks weak. You may want to test it. There are two high tension wires coming out of the coil. Using an alligator clip jumper wire, jumper 1 high tension wire to frame ground. Take an old spark plug and gap it to .100" or just remove the adjustable electrode. Connect the other high tension wire of the coil to this test plug. Connect the threaded portion of the plug to frame ground. Crank the engine using the starter and see what the spark looks like. It should be able to jump that free air gap.

No, unfortunately its not a Genuine H-D manual. The battery read 12.2 before I performed the voltage drop test. The battery stayed constant during the test. The white wires read initially 12.18 and stayed constant during the test as well.

I performed the jump test as you described and the spark did jump the gap.

As far as the module goes it reads 10.82 volts with the positive lead on the red wire and the negative on the black at the connector for the timing sensor.

Hoople, I really do appreciate you helping on this problem. Thank You.

 

[Hoople]

The white wires read initially 12.18 and stayed constant during the test as well.
I performed the jump test as you described and the spark did jump the gap.
As far as the module goes it reads 10.82 volts with the positive lead on the red wire and the negative on the black at the connector for the timing sensor.

Ok, then you have no voltage drop going to the battery side of the coil.
Has the ignition module been replaced since you started working on this problem? Or are you using the same module for the last several years.

You said you performed the spark jump test but you didn't say what the gap was. Did you remove the electrode off the plug. Was the gap a solid 5/16" gap. The plugs should still be removed from the cylinders which would have resulted in a nice fast cranking RPM during the test. Was the spark jumping with good repetition. Does it look healthy and fat?

I can't confirm what the reference voltage should be because I am using a knock off manual also. Maybe another member has a genuine year specific HD manual for an accurate spec.
10.82 could be ok, but it just doesn't sound right to me. My guess would be either 5v or battery rail voltage (12.50) but not 10.82.