timing sensor voltage

[rgoot01]

Control module voltage output?

Ok so I'm back to the control module and need some help. I was looking over my manual and it states that the voltage should read 4.5-5.5 when testing the control module at the connector for the timing sensor plate. When I hook up my multimeter to the connector with the positive lead on the red wire and the negative lead on the black I read 11.18 volts.

What would cause the reading to be double what is spec'd in manual?

 

[Hoople]

Re: Control module voltage output?

What would cause the reading to be double what is spec'd in manual?

You didn't say what module your testing, Also don't know year of bike or anything about the problem your having but assuming the manual does not have a type-o in it (non-Genuine HD manual) and your using the correct manual for that exact year bike your working on, then the module is bad. Sounds like your checking a 5 volt reference voltage and those voltages are generated within the module and are sent out to the sensors.

Be aware on some years and models a 5 volt reference was used and on some models a 12 volt reference was used. That's why it is important that the bike matches the manual used.

 

[Jack Klarich]

Re: Control module voltage output?

Ok so I'm back to the control module and need some help. I was looking over my manual and it states that the voltage should read 4.5-5.5 when testing the control module at the connector for the timing sensor plate. When I hook up my multimeter to the connector with the positive lead on the red wire and the negative lead on the black I read 11.18 volts.

What would cause the reading to be double what is spec'd in manual?

You didn't say what module your testing, Also don't know year of bike or anything about the problem your having but assuming the manual does not have a type-o in it (non-Genuine HD manual) and your using the correct manual for that exact year bike your working on, then the module is bad. Sounds like your checking a 5 volt reference voltage and those voltages are generated within the module and are sent out to the sensors.

Be aware on some years and models, a 5 volt references and some used 12 volt references. That's why it important that the bike matches the manual.

Is this the same bike that was referenced in an earlier thread where the module was changed to an updated 1 with an adapter harness? If so is this the correct harness for the bike?

 

[rgoot01]

Is this the same bike that was referenced in an earlier thread where the module was changed to an updated 1 with an adapter harness? If so is this the correct harness for the bike?

Yes, the same bike. The new module is 32405-91A and 32408-90 harness.

Also would like to state that I have checked the spark and it seems weak, honestly, my lawnmower has a fatter brighter spark.

You didn't say what module your testing, Also don't know year of bike or anything about the problem your having but assuming the manual does not have a type-o in it (non-Genuine HD manual) and your using the correct manual for that exact year bike your working on, then the module is bad. Sounds like your checking a 5 volt reference voltage and those voltages are generated within the module and are sent out to the sensors.

Be aware on some years and models a 5 volt reference was used and on some models a 12 volt reference was used. That's why it is important that the bike matches the manual used.

The manual is Harley's manual for 1984-1998 FLH,FLT,FXR with evoulution engine.

 

[Jack Klarich]

Re: Control module voltage output?

Also would like to state that I have checked the spark and it seems weak, honestly, my lawnmower has a fatter brighter spark.

What does your coil test out at?

 

[rgoot01]

Re: Control module voltage output?

What does your coil test out at?

Primary: 3.1 ohms
Secondary: 12,350 ohms

 

[Bodeen]

Re: Control module voltage output?

I merged the two threads of the same subject to keep it somewhat concise.

 

[Hoople]

Also would like to state that I have checked the spark and it seems weak, honestly, my lawnmower has a fatter brighter spark.

The manual is Harley's manual for 1984-1998 FLH,FLT,FXR with evoulution engine.

A manual that covers 1984-1998.? I thought Harley's manuals were pretty much year specific. But none the less,, what I would check first, is for a voltage drop across the coils primary terminals. That could certainly be the reason for the weak spark.

In order to check that, remove both spark plugs. Place the transmission in neutral and remove the Derby cover so you can slowly turn the engine by hand using a wrench on the clutch basket lock nut. Turn the ignition ON. Run/kill switch in RUN position. Place your voltmeter directly across the battery and record this value (12.XX).. This is value #1
Now clip your voltmeter between the positive coil terminal and to frame ground. The meter should read some value near battery voltage. Now as you slowly turn the engine by hand , watch the voltmeter. The meter reading should toggle between two valves. One may be 12.50 and the other may be 11.50. The lower one is the important one so record the lower number. This is value #2. Note: as you slowly turn the engine by hand, you may hear & see the coil fire so be aware.

While locked onto this lower voltmeter value, swing the bars back and forth to see if the meter value changes. Tug a little on the wiring harness at the bars. The voltmeter should remain constant. Now turn the ignition OFF and compare value #1 to value #2. They should be pretty near equal. If the 2nd reading is lower than the 1st reading by more than 1/2 volt, there is probably a good chance that is your problem for a weak spark.

 

[rgoot01]

A manual that covers 1984-1998.? I thought Harley's manuals were pretty much year specific. But none the less,, what I would check first, is for a voltage drop across the coils primary terminals. That could certainly be the reason for the weak spark.

In order to check that, remove both spark plugs. Place the transmission in neutral and remove the Derby cover so you can slowly turn the engine by hand using a wrench on the clutch basket lock nut. Turn the ignition ON. Run/kill switch in RUN position. Place your voltmeter directly across the battery and record this value (12.XX).. This is value #1
Now clip your voltmeter between the positive coil terminal and to frame ground. The meter should read some value near battery voltage. Now as you slowly turn the engine by hand , watch the voltmeter. The meter reading should toggle between two valves. One may be 12.50 and the other may be 11.50. The lower one is the important one so record the lower number. This is value #2. Note: as you slowly turn the engine by hand, you may hear & see the coil fire so be aware.

While locked onto this lower voltmeter value, swing the bars back and forth to see if the meter value changes. Tug a little on the wiring harness at the bars. The voltmeter should remain constant. Now turn the ignition OFF and compare value #1 to value #2. They should be pretty near equal. If the 2nd reading is lower than the 1st reading by more than 1/2 volt, there is probably a good chance that is your problem for a weak spark.

I tested as you suggested the battery reads 12.35 volts. The coil however at times while turning engine by hand it reads 12.06 yet dropped at times to 8.6 and once dropped to 1.22. I assume that I would need a new coil?

 

[Jack Klarich]

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