Honda Quad - No Spark after getting warm

[BROWNIE59]

Hi all;
new member looking for some assistance.
Issue: Honda 420 FPA 2011 Quad stops after running approx 15-20 mins. No spark at plug lead.
Wait 20mins and starts fine, then stops 5-10 mins later - No Spark.
Actions: 1. Researched on I/Net, took advice and replaced Relay Module behind Seat. Result No Change
2. Heated and then cooled ECU - nothing conclusive
3. Sought info from place of purchase re Crank Shaft Position Sensor Coil
Info; Disconnect from LOOM and measure at plug (On RHS of Seat) Should measure 240 Ohms
Result; When disconnected from Loom and inserting dress making pins into wires, My Coil measured 120 Ohms
4. Reconnected plug to Loom, fitted Alligator Clips to Pins connected to Multimeter AC Volts, Started engine and let idle.
Result; Multimeter measured 2.9 Volts AC
5. Observed Multimeter, and as the mins ticked up, voltage slowly decreased.
Result; Just before motor stopped, multimeter showed 0.5 Volts AC.
6. Checked spark
Result; Nil Spark.
7. Disconnected Plug to Loom
8. Measured Pins (Wires to Crank Shaft Sensor Coil)
Result; Open Circuit (Infinite Ohms)
9. Allowed to cool 30 mins
10. Results; 120 Ohms.

Conclusion: Faulty Coil or Coil Solder connection inside Crank Case.

Future; 1. Cannot purchase Coil only, complete Alternator Stator/Coil from Honda $550.(Plus Manual says remove the motor from Frame.)
2. Found company in Geelong who rewind coils but have to remove Coil and show them to confirm if they can rewind (Approx $250)

Current Thinking; Will try removing Quad rear suspension, attempt to remove Rear Crankcase, resolder Coil Connections, refit crankcase and restart motor to see if the problem is solved.

Any comments or suggestions would be welcome.

Regards; Graeme

[wotnot]

Conclusion: Faulty Coil or Coil Solder connection inside Crank Case.

Yeah, likely correct going by those diagnostics. Seeing as CKP sensor read half what it should be off the bat, you'd be looking at broken solder joint as you suggest, or, broken coil winding. Of course, the only way to ascertain that position is to pull the CKP apart (often destructively to a point), and sus it out....

...second thought is, perhaps a chinese knockoff exists based on this Honda (engine) design, or, aftermarket CKP sensors exist (need honda part number if it exists) ~ if there was, sourcing a CKP sensor from there would be cheaper =)

[SS Dave]

I had a Honda quad called Big Red that the customer had similar issues.

It had a faulty CDI module, That fixed it for around 6 months then it also developed poor connections on the wire crimps in the CDI module plug.

I have also seen quite a few failed CDI pickup coils in other bikes.

This part.



A quick google shows a few non OEM Stator assemblies that come with a new pickup.

[BROWNIE59]

Hi Guys;
thankyou for input from Wotnot and SS Dave. Sorry for the late reply as I forgot my PW etc.

Update: 1. Have removed the Quad Rear Suspension assy completely (two bolts plus Brake Hose). Its much easier than removing motor As instructed by manual.
2. Removed the Motor Rear Crankcase (need to remove starter motor) with some jiggling.
3. Removed the Stator and Pulse Coil from Crank Case.
4. Cleaned the two solder joints (were two wires to Alternator Plug join Pulse Coil), with Thinners, desoldered, then resoldered.
Note: Did apply a little more heat to Coil Pins than usual. Hoping it may refresh Coil Wires to Pin connections inside potting
5. Refitted Stator (Loktite to Pulse Coil Bolts)Cleaned crank case joint, applied sealant, and with a lot of jiggling refitted Crank Case.
TRAP: Need to ensure Gear Position Drive Pin is lined up with 'N' Mark on Crank Case and Gear Box in NEUTRAL.
6. Refilled motor oil next day.
7. Started and let idle for in excess of 1 Hour (Thermo Fan started twice) Previously used to stop (No Spark and Pulse Coil Open Circuit) after 15 -20 mins.

Conclusion: May have fixed the issue ???????? Will not know until I give it a good test run after replacing some CV Boots on Rear Suspension.

Hope this may be of help to others.

Regards; Graeme

[wotnot]

Did you check resistance of CKP as before, to compare the readings before/after repair attempt? If the resistance is now within range, yes, you may have fixed it =)

[BROWNIE59]

1. Did check resistance and all looked same as before resoldering joints on Pulse Coil.
2. Finally repaired CV Boots etc and placed Rear End back onto Chassis. Started first go and took it for a ride.
3. All ok for about 30 mins then it died (Just like you turned Key Off)
4. Waited 30 mins - started fine - took it back to shed quickly.

Conclusion: Pulse Coil still faulty OR something else???

Next Step; Will try replacing Pulse Coil with after market item. Lucky my time is cheap!!!

[wotnot]

Right about now is where I'd hookup my USB DAQ (like a picoscope) to have a look at the CKP signal. Typically what you see, is the voltage amplitude dropping as the coil heats up (higher resistance)... most folks don't have this gear, but from a diagnostics perspective that's your next port of call. Seeing as the CKP measures dodgy anyway, I'd say it's a fair candidate for the 'parts cannon'... =)

Cautionary tale ...I once fixed a suzuki ATV with a dead CKP (easy one, measured open circuit), by using an aftermarket CKP ~ the wire colours differed from that of the OEM unit (black & blue vs OEM black/white & yellow iirc) ~ I made the 'obvious' choice of connecting black to black/white, blue to yellow. Engine immediately started and ran fine, but would not rev past 3000rpm or so, faltering, exhaust backfire ...on a hunch, reversed the CKP wiring ; engine started and would rev it's tits off... lesson learned =)