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Hello gents. It´s been a while!! Thanks in advance for dedicating time to read this.
A customer came with this Van to my shop complaining for a long start. The car has been here for a couple of days in which i had experienced the issue. It takes something about 6 seconds cranking to get start the engine in the very first try, then starts inmediately. It also sat P0300 code while cranking.
The first test i did was turn the pump on before cranking with scanner and it started also inmediately, so for sure is fuel pressure at starting moment. I confirm is not a leak but a false electrical contact in Run/Start relay and fuse#25 (sometimes when ignition switch on, fuel pump didn´t turn on). Now fuel pump is turning On every time i request it and now engine is starting at the very first try, with an exception as follow.
There is something weard. It is supposed every time you turn ignition key on the fuel pump turns on for about 3.5 seconds. The condition to get those 3.5 seconds, is you take the key to on position rapidly. Otherwise you loose that time.
For intance let´s say you do a pause of 2 seconds in ACC position and then you turn to On position. Now you have only 1.5 seconds to raise pressure in fuel system. It seems like the trigger for fuel pump timer triggers in ACC position and even when timer is now running, order to turn fuel relay is in On position. The worst issue is if you loose those 3.5 seconds in ACC position and then you turn to ON, you wont have any time to raise pressure. If you wnat that time again, you have to turn key back to Off position and start again.
Off course if you loose that time and you crank it, you are going to have fuel pressure at the end of the day and you are going to start the engine (becuase pump turns in while cranking), but you are going to have a 3 seconds cranking.
By the way. TIPM feeds voltage pin and PCM feeds ground pin for fuel pump relay. Both (TIPM & PCM) receives start signal (and i suppose fuel priming also) from WIN through CAN message.
