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Louie
Louie, Technician
Category: Motorcycle
Satisfied Customers: 12664
Experience:  25+ yrs. experience
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Put new cdi in and atv will crank, but no spark in plug.

Customer Question

put new cdi in and atv will crank, but no spark in plug.
Submitted: 2 years ago.
Category: Motorcycle
Expert:  Louie replied 2 years ago.

Hi and welcome back to JustAnswer,

Thank you for the question and your patience. Should you still need assistance for information purposes only...

Initially, on "...What should the voltage be on CDI light blue wire ?with key on or key on and cranking..."; on any instance, the light blue wire should have 0V as it would be tied to the ground through the neutral switch.

On the other hand, the black/white wire should not be tied to the ground to allow the CDI to fire.

Customer: replied 2 years ago.
I took black/white and light blue wire out of new cdi and atv cranks and runs and have to ground it to kill engine just like the old cdi acted
Expert:  Louie replied 2 years ago.

Grounding the black/white should kill the CDI/engine, hence check the kill switch and its wiring (including the ignition switch).

Grounding the light blue wire would "simulate" neutral switch action and would allow cranking.

The black/white and the light blue serves two (2) separate/different interlock functions and has nothing to do with each other except served by the same CDI.

Remove the new CDI and battery connections. Test with a continuity/ohmmeter both the harness' black/white and the light blue wires (again CDI disconnected) with respect to engine ground:

  • • kill switch/engine On/Off - black/white wire no reading/0Ω;
  • • ignition switch On/Off - black/white wire no reading/0Ω;
  • • in neutral - light blue wire 0Ω;
  • • in gear - light blue wire no reading.

Repeat test using frame as ground.

And then again with - battery cable as ground.

Customer: replied 2 years ago.
hello: with ohm meter set on 200 scale and red and black battery cable disconnected. ....black/white-2 light blue-4.3..........engine ground...kill switch on-2.0....run-28...black battery cable...... kill switch on 2.2....run-2..........frame ground....kill switch on-1.8...run-2.2 ................ignition switch on/off....engine ground- 26/2.1.....frame ground..2.5/10.2......black battery cable- 21/2.2...........................in neutral light blue-engine ground-3.1....frame-3.5....black battery cable-4.3...................in gear light blue ...engine ground-24.8...frame-24.5....battery black-24.3
Customer: replied 2 years ago.
Customer: replied 2 years ago.
I have appointment , will be gone about 2 hours
Expert:  Louie replied 2 years ago.

There appears to a lot of disparity when different grounds are used; engine, frame and battery - cable. Normally, these three (3) should give equal readings as all are tied to the same ground. Consider hardwiring:

  • • a second ground line from the engine to battery - cable;
  • • a third ground line from the frame to battery - cable; and
  • • a fourth ground line from the harness' black wire to battery - cable.
Customer: replied 2 years ago.
Is CDI not the problem ???
Customer: replied 2 years ago.
I used emery paper and electrical contact cleaner on all the ground to frame-engine and battery .
Expert:  Louie replied 2 years ago.

Based on the previous tests and the above post of "...will crank...", the new CDI seems to have fixed the "... will not crank..." making the old CDI partially faulty.

UN-grounding the black/white wire of the new CDI should allow the CDI to fire the ignition coil = spark:

  • • if not, then the new CDI is also partially faulty (most likely); or
  • • a wiring, connector, sensor issue (least likely).
Customer: replied 2 years ago.
I ran new ground wires to frame, engine, ignition switch, CDI, voltage reg, etc. ATV will not crank and even with black/white and blue wires disconnected from CDI it will not even crank or run like it would before.
Expert:  Louie replied 2 years ago.

What wire color(s) of the "...ignition switch, CDI, voltage reg, etc..." were tied to the "...new ground..."

And can you please re-check the battery voltage:

  • • ignition OFF;
  • and then when ON;
  • • when attempting to start the engine.
Customer: replied 2 years ago.
Black
Customer: replied 2 years ago.
Battery voltage with trickle charger on.
ignition switch off-13.18
ignition switch on-13.16
Expert:  Louie replied 2 years ago.

Sorry, measure battery voltage with no charger connected. Please repeat above checks.

And re-try momentarily jumping the 2 big terminals of the starter relay/solenoid.

Post back results / observations of the above once tried.

Customer: replied 2 years ago.
with no charger
ignition off-12.84
ignition on 12.83
push start button 12.83
IT cranked and started when shorted across start relay
Expert:  Louie replied 2 years ago.

"... IT cranked and started..." - will it shut off when ignition switch is turned OFF?

Customer: replied 2 years ago.
when shorted across start relay it cranks and runs. No will not shut off when key is turned off.
Customer: replied 2 years ago.
Have to take mom to dr appt.. Will be gone awhile.
Expert:  Louie replied 2 years ago.

I understand; later when able then.

Customer: replied 2 years ago.
what is going on with this thing ??
Expert:  Louie replied 2 years ago.

"...will not shut off when key is turned off..." would point to possibly a faulty ignition switch and/or a connector/wiring issue with the black/white and black wires.

Would it shut off with the Engine STOP switch?

Customer: replied 2 years ago.
Will not shut off with kill switch
Expert:  Louie replied 2 years ago.

But will grounding the black/white wire of the CDI shut the engine off?

Customer: replied 2 years ago.
ground to black/white does not kill engine
Expert:  Louie replied 2 years ago.

Appreciate your patience.

"...ground to black/white does not kill engine..."; would this be CDI's black/white wire to CDI's black wire? (...and not just momentarily)

Customer: replied 2 years ago.
CDI black/white wire and new ground from battery black to CDI black on to the CDI black/white wire.
Ignition switch disconnected
switch in off position
black to black/white ( with ohm meter)-continuity
switch red wire to brown wire-open
switch in on position
black to black/white-open
switch red wire to brown-continuity
looks like switch is ok
Customer: replied 2 years ago.
switch connected and on brown to black gives 12.6 volts.
Expert:  Louie replied 2 years ago.

With the CDI completely disconnected from the Grizzly's harness/connector, what is the resistance reading between the CDI's black/white wire to CDI's black wire? ...

What are the other wire colors of the CDI?

Customer: replied 2 years ago.
CDI's black to black/white is open
other wires -orange-brown-yellow/black-green/white-green/yellow and the black and black/white
with CDI disconnected I have 12.6 volts on the yellow/black wire to new black and with harness black
Expert:  Louie replied 2 years ago.

Thanks.

To my recollection, the original CDI has 2 faults; will not permit cranking and will not produce spark.

This new CDI will now permit cranking and produces spark EXCEPT will not turn OFF.

Based on the above, the new CDI is also partially faulty.