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Recently an intermittent problem developed to engine can crank but don't fire, a couple weeks ago,the engine had 2,3 times die when towed a rider, after that, seems no problem and back to trailer But I think that there should be some thing wrong , next week ,try to run the engine on trailer ,don't fire at all , find that no spark and no input voltage on primary coil , and found there are no power to both fuel pump relay, obvious ,there are relations , jumping a +12v to one of the relay’s pin 86, some high frequency noise can be heard from the HV coil ,start the engine ,it runs as normal , by this way, the keypad can't stop the engine ,need disconnect +12v ,can't trace by one day where the positive 12v of the coil of relay come from, this +12v supply the fuel pump relay and spark circuit and controlled by keypad PME box (the breaker box on the kicking board) ,once keypad "start''ed, it exist, had read some topic about fuel pump relay circuit, DanieIC explained well in some aspect, but my case seems not the same ,any though? the engine is GT-40 EFI on 01 SAN.
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Both the fuel pumps and the engine control computer are switched by the two relays. Both of the relays should have 12 volts on terminal 30 at all times. The key, or switch box/touchpad combo applies power to terminal 86 of the computer relay, it has a hard wired ground. That applies power to the computer, and the ignition circuit, and to terminal 86 of the fuel pump relay. The computer controls the ground of the fuel pump relay.
Make sure you have 12 volts at terminal 30 on both relays.
Do not run your engine without supplying cooling water to the raw water pump at all times. Not even a little bit. -
Thanks DabieLC input ,could not trace where the 12V lost, 86 pin goes to several computer's pins ,computer PCB looks nice,no corrosion, any hints ? next day will check it again.Comment
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GT-40 EFI fuel pump circuit need
Before go to check the boat, looking for the citcuit diagrm, any body know where can get? for keylees 01SAN.Comment
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RE: GT-40 EFI fuel pump circuit need
DIODE, EEC relay pin 86 get 12V via a diode, problem may be the diode, anyone know where is the diode ?Comment
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Download the gt-40 service manual, it is in the downloads section of this web site. In section 6, page 8 of the manual you will find the fuel pump circuits.
Like I said before, 12 volts must be on pin 30 of both of the "bosch" type cube relays, anytime the battery is hooked up. There is no battery drain from this connection, because pin 30 is just an open switch connection, until the relay coil is energized.
The power to energize the relay coils gets to the motor on a purple wire. This wire can be found on a plastic 10 pin connector on the back of the motor, somewhere between the starter, and the metal panel that holds the engines computer, and other electronics.Comment
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