2004 225 Start and die

[badger3133]

I have a 2004 225hp that will start up and then die after one second.

[Harper]

Weak battery, loose or corroded cables and wires, especially white wire, dirty connections. ECU hates such things. Any voltage drop or low voltage will cause ECU to shut down the motor, and it seems especially touchy during or right after starting.

[badger3133]

Tested all of that, i have good fuel pressure 38 psi, have spark on all 6 plugs, have crank signal and cam signal clean 12v on white wire. it still starts of 1second and dies

[Murray]

Water in the fuel?

[badger3133]

no, no water in the fuel, it seems electrical because it does fire and then instantly dies, it was running fine after i replaced the water pump, and then when putting it on the trailer it just died, since then it will just start and die.

[redlowrey]

It sounds like your iac valve is not moving to the commanded position when the key is in the start position and there is not enough air bypassing the throttle plate, so it will try and keep running but the starting fuel is too much so it stalls. Or the temp sensor signal voltage is too low and there is not enough cold start fuel being injected.

also a lot of times these Mitsubishi type stepper motors will flare up on start up and stall if there is excessive voltage drop on start up. Use the manual throttle switch to open the throttle and see if it starts and runs ok, come back with the results, if it still won't start I will tell you some other things to check.
There could be numerous reasons why it won't start, but start with the manual throttle switch that will give me some direction to take if it does not work.

[badger3133]

used the manual throttle switch and it sits there and purrs like a kitten, Thanks