Fuel pump won't turn on unless "power up" wire is grounded.

[BailYes]

Hello all, We just installed a Motec M400 on a buddies FX SHO. The fuel pump will not turn on unless we ground the "power up" wire. When its grounded, whenever the start button is pressed, the motor cranks and the fuel pump turns on. Even if the "power up" wire is disconnected as long as the start button is pressed before the ecu shuts off ( 30 sec or so) the pump will turn on. Now once the ecu is off if the start button is pressed the motor will turn over, but the fuel pump will not turn on. Any ideas?

Thanks in advance!

Joey

[MoTeC Pete]

Joey

Hello all, We just installed a Motec M400 on a buddies FX SHO. The fuel pump will not turn on unless we ground the "power up" wire. When its grounded, whenever the start button is pressed, the motor cranks and the fuel pump turns on. Even if the "power up" wire is disconnected as long as the start button is pressed before the ecu shuts off ( 30 sec or so) the pump will turn on. Now once the ecu is off if the start button is pressed the motor will turn over, but the fuel pump will not turn on. Any ideas?

Thanks in advance!

Joey

Hi Joey
Strange and a little hard to understand
So your saying motor wont go as there is no fuel pump operation?
But if you earth the power up wire (which shorts the main relay) everything works normally?
Some questions for you

1. Where are you located
2. Was the system brand new?
3. Where did you buy it from?
4. Is the ski modified in anyway?

Cheers

Pete

[BailYes]

Exactly, If the power up wire is not grounded the fuel pump will not turn on. The motor will turn over, but it will not start as there is no fuel pressure. Once the power up wire is grounded the fuel pump will turn on when the start button is pressed, and the motor will turn on (now having fuel pressure).

1. I am in Miami, Fl.
2. System was bought used.
3. Bought from a friend.
4. The ski is a built turbo motor. (Just for reference, I also have a Motec on my personal ski. Which is a carbon copy, modification wise, of my buddies ski. My Motec does not have this issue.


Thanks for your reply. I hoped this would be simple programing issue. Now I'm getting worried....

[MoTeC Pete]

Exactly, If the power up wire is not grounded the fuel pump will not turn on. The motor will turn over, but it will not start as there is no fuel pressure. Once the power up wire is grounded the fuel pump will turn on when the start button is pressed, and the motor will turn on (now having fuel pressure).

1. I am in Miami, Fl.
2. System was bought used.
3. Bought from a friend.
4. The ski is a built turbo motor. (Just for reference, I also have a Motec on my personal ski. Which is a carbon copy, modification wise, of my buddies ski. My Motec does not have this issue.


Thanks for your reply. I hoped this would be simple programing issue. Now I'm getting worried....

Its sounding like a wiring problem to me
Can you swap the adapter loom over with your personel ski
If no difference then do the same with your personal ECU, obviously change the file over also
If still no difference then the issue is in your ski wiring.

Let me know what happens

Regards

Pete

[BailYes]

Will do later today. Will get back to you with the results.

Thanks Pete!

[BailYes]

Hey Pete,

I swapped the adapter harness and the problem went away! I inspected the bad harness and found a broken solder connection where it meets a diode (red wire). I will solder it in the morning and that should do it. I will let you know how it goes tomorrow. I appreciate your help. I was blinded with the thought that it was a programing issue because I figured that if there was a broken wire it would not work at all.


Thanks Again! I will let you know how it turns out tomorrow.

[BailYes]

Problem solved! Thanks again Pete!

[MoTeC Pete]

Problem solved! Thanks again Pete!

Great
Thanks for letting us know

Cheers