2003 f225 4stk no fuel

[ricwing]

My 03 F225 4stk. will not start and run unless pump the primer bulb,will run a few minutes go dead. found low pressure fuel pump not coming on, removed and benched test and it worked, check fire had fire, check for ground no ground from relay, b/w ground wire went to ecm, check wire was ok, possible bad ecm? ask a yamaha tech said had never had to replace an ecm,they just don't go bad. would give any more info. does ecm have some other sensor to tell it to give ground to low pressure fuel pump.
Has anyone had this problem and can help me,

 

[rodbolt]

Re: 2003 f225 4stk no fuel

on that motor the lift pump runs 20 seconds then off 20 seconds.
anytime the key is on the red/yellow will be hot. the ECM will complete the ground every 20 seconds for 20 seconds when the engine is running.

 

[ricwing]

Re: 2003 f225 4stk no fuel

Then it must be the ECM?,or is there another sensor telling the ECM to cycle the pump?

 

[rodbolt]

Re: 2003 f225 4stk no fuel

dunno. as you wont post wire colors and voltage readings, all I can say is if you buy an ECM, you will most likly have a spare ECM.

 

[ricwing]

Re: 2003 f225 4stk no fuel

I agree, have set up appt. with dealer service dept. for next week,i will post results when fixed, thanks

 

[ricwing]

Re: 2003 f225 4stk no fuel

Lift pump ak low pressure pump was failed part, called myself bench tested it, and tested good

 

[rodbolt]

Re: 2003 f225 4stk no fuel

what? i did not understand that last one.
once the engine is running the lift pump cycles at 20 second intravels.
the red/yellow wire has 12v any time the key is on, the ECU controls the ground path for the low speed pump cycle times, above 1800 or so the pump is a constant run.

 

[ricwing]

Re: 2003 f225 4stk no fuel

Yes the low pressure pump was bad, when i tested it had 12v but no ground
to the pump.traced ground wire from what i call a relay to the ecm.I could ground pump and would run. I took to dealer b/c i was concern it would not
be the ecm,alot of money,well the pump and labor was $951.00 not cheap either. But still confused of how the ecm gets a signal, from the ignition switch? Don't know but motor runs great now.

 

[rodbolt]

Re: 2003 f225 4stk no fuel

at key on the ECU cycles the high pressure pump, it gets a run signal from the pulser coil and crank position sensors to aid in ign timing,ISC and lift pump on/off times. but on most of yamahas electronics 12v is supplied and the ECU controls the ground path.

 

[ricwing]

Re: 2003 f225 4stk no fuel

rodbolt, thanks for the info., way over my head