2011 TRX500FPM no spark when hot.

[retro 4,049]

I've never seen a bad TPS kill spark either, but it should be replaced if it's bad to rule out that possibility.

[jeepwm69 7,627]

Current weird thing this machine is doing.  Machine has completely lost spark now.

 

@retro @Melatv any ideas.  Rich asked me to check my footshift 500 and see if the same thing happens. I’m at work now so will be a bit

[shadetree 5,889]

52 minutes ago, jeepwm69 said:

Current weird thing this machine is doing.  Machine has completely lost spark now.

 

@retro @Melatv any ideas.  Rich asked me to check my footshift 500 and see if the same thing happens. I’m at work now so will be a bit

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you having trouble with that same 500 again ?..man..toss that 500 in the Mississippi river..lol.

[retro 4,049]

1 hour ago, jeepwm69 said:

Current weird thing this machine is doing.  Machine has completely lost spark now.

 

@retro @Melatv any ideas.  Rich asked me to check my footshift 500 and see if the same thing happens. I’m at work now so will be a bit

IMG_3541.MOV 13.14 MB · 0 downloads

 

The gear position switch tests good when in neutral. The reason why the multimeter fails to measure continuity (resistance actually) when the ignition switch is turned on is because multimeters cannot function in resistance modes while there is voltage present. Resistance & continuity tests must be performed with the ignition switch off, or the battery disconnected (or the circuit under test unplugged/isolated from voltage).

[retro 4,049]

In case this is useful.... a member recently measured a new OEM ignition coil (2010 420 Rancher) and provided us with the specs. I think your model uses the same part number... Resistance between the two primary winding terminals on the coil should measure around 2.75 ohms. Between each primary terminal and the end of the spark plug cable should measure around 18500 ohms (18.50K ohms). Between each primary terminal and ground (the stack of metal plates on the end of the coil is ground) and between the end of the spark plug cable and ground should all measure open circuit. 

 

If the coil measures close to those specs try running a jumper wire from the positive battery post to the Red/Black terminal on the coil with the coil still plugged into the harness. See if you get spark.

 

You may have to recheck the peak voltages on the CKP and at the coil, make sure that one of them haven't failed since you first tested them.

 

The ignition switch is a suspect in my mind. I've seen them fail intermittently and under load, opening the ignition like yours was doing after a few minutes of runtime. 

[jeepwm69 7,627]

2 hours ago, shadetree said:

you having trouble with that same 500 again ?..man..toss that 500 in the Mississippi river..lol.

 

Nope!  This one isn't mine, just trying to help him diagnose a 2011 TRX500FPM (footshift with power steering)

[jeepwm69 7,627]

33 minutes ago, retro said:

In case this is useful.... a member recently measured a new OEM ignition coil (2010 420 Rancher) and provided us with the specs. I think your model uses the same part number... Resistance between the two primary winding terminals on the coil should measure around 2.75 ohms. Between each primary terminal and the end of the spark plug cable should measure around 18500 ohms (18.50K ohms). Between each primary terminal and ground (the stack of metal plates on the end of the coil is ground) and between the end of the spark plug cable and ground should all measure open circuit. 

 

If the coil measures close to those specs try running a jumper wire from the positive battery post to the Red/Black terminal on the coil with the coil still plugged into the harness. See if you get spark.

 

You may have to recheck the peak voltages on the CKP and at the coil, make sure that one of them haven't failed since you first tested them.

 

The ignition switch is a suspect in my mind. I've seen them fail intermittently and under load, opening the ignition like yours was doing after a few minutes of runtime. 

 

This is a carb'd, air-cooled 2011 500.   Not mine.  I've been trying to help him troubleshoot it.

[jeepwm69 7,627]

41 minutes ago, retro said:

In case this is useful.... a member recently measured a new OEM ignition coil (2010 420 Rancher) and provided us with the specs. I think your model uses the same part number... Resistance between the two primary winding terminals on the coil should measure around 2.75 ohms. Between each primary terminal and the end of the spark plug cable should measure around 18500 ohms (18.50K ohms). Between each primary terminal and ground (the stack of metal plates on the end of the coil is ground) and between the end of the spark plug cable and ground should all measure open circuit. 

 

If the coil measures close to those specs try running a jumper wire from the positive battery post to the Red/Black terminal on the coil with the coil still plugged into the harness. See if you get spark.

 

You may have to recheck the peak voltages on the CKP and at the coil, make sure that one of them haven't failed since you first tested them.

 

The ignition switch is a suspect in my mind. I've seen them fail intermittently and under load, opening the ignition like yours was doing after a few minutes of runtime. 

 

Looks like he's dropping ground to the coil.

 

Pretty much replaced everything electrical on the machine except the wiring harness. 

[rich250rracer 1]

4 hours ago, retro said:

 

The gear position switch tests good when in neutral. The reason why the multimeter fails to measure continuity (resistance actually) when the ignition switch is turned on is because multimeters cannot function in resistance modes while there is voltage present. Resistance & continuity tests must be performed with the ignition switch off, or the battery disconnected (or the circuit under test unplugged/isolated from voltage).

Electrical is not my forte, but with a good service manual, my peak voltage meter, and some probes I can usually pick my way through this stuff. While I kind of grasp what you are saying here, forgive me if I seem skeptical. The reason for that is while the green/red wire in the harness for the gear position switch loses ground when I turn the key on, BOTH of the green ground wires at the ECU do NOT. I back probed those, and used the same ground as when I tested the neutral position wire. This is one of the items Honda lists in the trouble shooting for no peak voltage at the coil.

[retro 4,049]

6 hours ago, rich250rracer said:

While I kind of grasp what you are saying here, forgive me if I seem skeptical. The reason for that is while the green/red wire in the harness for the gear position switch loses ground when I turn the key on, BOTH of the green ground wires at the ECU do NOT.

 

If I'm following you right, the two green wires in the ECU connector are direct to frame grounds, so no voltage is possible on those unless/until the ECU is plugged in and key is on. You can measure the DC volts present on those two green ECU wires after unbolting them from the frame but that's not advised because ECUs are expensive, delicate & fragile gizmos. Seems like they can fry if ya just cuss at them one too many times.....

 

While the Green/red neutral switch to ground wire completes the circuit for the neutral light and the N indicator on the dash, as well as provides the ECU with a neutral gear signal and on most Hondas completes the circuit for the starter solenoid, so the voltage present that overwhelms the multimeter resistance mode is being provided by the dash display. If there were no voltage on the Green/red (in neutral with the key on) the neutral light would not have lit up in your video. You can find out how many volts are on that Green/red gear position switch wire by unplugging the switch and probing from the Green/red to ground in DC volts mode, with the key on.

 

Multimeters cannot handle voltage while in any resistance or continuity modes. If voltage is sufficient the meter will fry while in resistance mode. That's a well known fact... That's why multimeter instructions always remind the user to use AC volts mode on high range when probing an unknown circuit. Then drop to DC volts mode to insure that no voltage is present before resuming testing in other modes.

 

EDIT: Just to add info on why multimeters cannot function in modes other than Volts or Amps in live circuits, the battery in the multimeter is used to provide voltage for measuring resistance, capacitance, inductance etc. modes in a closed circuit to the probes. If your meter has a 9 volt battery in it then it sends 9 volts through the measuring probes.... if it has two 1.5 volt batteries in it then it sends 3 volts through the measuring probes.

 

One or two 1.5 volt batteries powering multimeters are becoming more common nowadays - because many modern sensitive electronic chips will fry if they receive more than 1.5v or oftentimes more than 3 volts while being measured - 9 volt meters are obsolete. If you introduce external voltage while measuring you can fry stuff.... the multimeter as well....

[retro 4,049]

So.... what I'm saying is your gear position switch is fine, else the neutral light would not light up on the display and the starter would not work when you press the starter button.

 

Your no spark issue is a head scratcher for sure!

[retro 4,049]

7 hours ago, rich250rracer said:

This is one of the items Honda lists in the trouble shooting for no peak voltage at the coil.

 

So you aren't getting any peak voltage at the Black/yellow coil wire?

 

 

Try reversing the polarity of the Peak Voltage Adapter leads between Black/yellow and ground on the coil (positive PVA lead on Black/yellow, negative PVA lead on ground) and see if you get any peak voltage?

 

Your multimeter should be dialed to DC volts mode, since the PVA uses a diode to capture 1/2 waves of the CKP sensor AC sine wave voltage and stores those 1/2 waves (now rectified DC rather than AC voltage) in a capacitor inside the PVA.

[rich250rracer 1]

9 hours ago, retro said:

 

So you aren't getting any peak voltage at the Black/yellow coil wire?

 

 

Try reversing the polarity of the Peak Voltage Adapter leads between Black/yellow and ground on the coil (positive PVA lead on Black/yellow, negative PVA lead on ground) and see if you get any peak voltage?

 

Your multimeter should be dialed to DC volts mode, since the PVA uses a diode to capture 1/2 waves of the CKP sensor AC sine wave voltage and stores those 1/2 waves (now rectified DC rather than AC voltage) in a capacitor inside the PVA.

I have a true peak voltage meter, I never trusted the adapter that I bought. I bought an ESI 530 DVA multimeter hoping for better results. Running the troubleshooting that Honda has outlined. Originally this problem would arise when the machine reached operating temperature, but it will not start at all now. No spark! I now have no peak voltage to the coil. Nothing. I have wiggled, pushed and probed the ECU connections. I have voltage at the black/white wire of the ECU, from what I can see there is connection of the green ground wires to the ECU (continuity between those green wires and the frame with the key on or off), appears as if the gear position switch is working correctly since it shows all gear positions. I have checked peak voltage from the new CKP, first from the plugs at the ECU and PS module, then at the plug from the CKP as Honda recommends. Both readings are in spec.

Edited 11 hours ago by rich250rracer

[retro 4,049]

The ESI 530 should be trustworthy. What is the peak voltage of the CKP sensor measured at the ECU connector? What was the peak voltage at the ignition coil before it lost spark?

 

I've been too busy to chime in up to this point, but I'll try to check back here a couple times a day. Odds are we can fix it.

[rich250rracer 1]

3 hours ago, retro said:

The ESI 530 should be trustworthy. What is the peak voltage of the CKP sensor measured at the ECU connector? What was the peak voltage at the ignition coil before it lost spark?

 

I've been too busy to chime in up to this point, but I'll try to check back here a couple times a day. Odds are we can fix it.

I will recheck and get exact readings, but I remember peak voltage at the coil being above 100v. 

[rich250rracer 1]

7 hours ago, retro said:

The ESI 530 should be trustworthy. What is the peak voltage of the CKP sensor measured at the ECU connector? What was the peak voltage at the ignition coil before it lost spark?

 

I've been too busy to chime in up to this point, but I'll try to check back here a couple times a day. Odds are we can fix it.

I think I misspoke in my video. Continuity wasn’t the terminology I was looking for. That gear position switch isn’t hot, there is never power to it. All it does is provide a ground to the appropriate wire that goes to the ECU, and the display on the dash. In essence, I was trying to determine that it was indeed providing that ground, which I should have realized it was, since it displays properly on the dash. So what I was doing was confirming that the green/red wire was indeed grounding as it should…..until I turned the key on. Why would the ground disappear? And since the coil is grounded to the frame, like the green/red wire in my test, is it losing ground when I turn the key on?

Edited 49 minutes ago by rich250rracer