How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Louie Your Own Question
Louie, Technician
Category: Motorcycle
Satisfied Customers: 12295
Experience:  25+ yrs. experience
Type Your Motorcycle Question Here...
Louie is online now
A new question is answered every 9 seconds

I have a 2013 700 yardsport made by hisun it ran good but

Customer Question

I have a 2013 700 yardsport made by hisun it ran good but the fan quit now it will not start the fuel pump and the spark system do not have ground when u crank it
Submitted: 10 months ago.
Category: Motorcycle
Expert:  Louie replied 10 months ago.

Hi Vivien, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.

Initially, proposed preliminary checks (if have not been done) on:

  • fan quit - test by bypassing the engine coolant temp sensor/switch and/or directly hardwiring to a +12V supply;
  • will not start - will not crank? if yes, bypass the starter relay/solenoid for test purposes;
  • fuel not have ground - check the fuel pump module, its wire, presence of IGN+12 and switching line from ECU;
  • spark system do not have ground - check for pulsating voltage from the ECU.
Customer: replied 10 months ago.
my fan works when i wire it direct. the fuel pump works when i ground it manually. the spark system has 12 volts when it is tested from pos wire to engine ground 6 volts when tested from wire to wire on plug in
Customer: replied 10 months ago.
checked the spark with a different meter it showa 12 volts through the wires same when cranking but it does not pulsate
Expert:  Louie replied 10 months ago.

I understand.

All of the above would indicate the absence of a drive voltage from the controller; the ECU. Offhand, suspect would then be a faulty ECU (least likely) or a sensor feeding the ECU (most likely).

It is possible for the no-spark and the no-fuel pump to be triggered by the same failed sensor BUT it would be unlikely for the fan motor to no-spin with the same sensor.

Re-inspect the ECU and its connector/wiring.

Post back with a clear closeup picture. Please click HERE.

Verify that the ECU is receiving IGN+12V and that the sensors are receiving their own SB+.

Customer: replied 10 months ago.
tried to send picture but failed where would the sensor be and would it be normally closed or open also can it be jumped to get it started
Expert:  Louie replied 10 months ago.

Let's start with a review of the basic; for the spark, the ECU's CDI has to receive a pulsating low voltage from the pickup coil. Characteristics of the pickup coil:

  • coil resistance ~ 500Ω;
  • output peak voltage ~ 1V;
  • in most versions, the pickup coil is co-located in the stator area.

Related Motorcycle Questions