Learn me on Fuel pump duty cycle

[speed1st]

And just how does one do this? My Predator can only datalog certain parameters and pump voltage, and lookup table voltage are not on the list.

So I have a 2005 mustang gt 4.6 3 valve. My fpdc is reading 0.50 steady! Doesn’t move. At idle or WOT. So I’m assuming that my pump is running at 100% all the time correct? Because I have nothing after 4700 rpm!! I’m using a sct x4 tuner. Am I reading this correctly? If so I need a new pump asap. Someone please help.

Reference Thread

Learn me on Fuel pump duty cycle

Hey, just figuring out how to Data-log for the first time. Trying to figure out why its falling on its face around 5000rpm under full throttle. What should my fuel pump duty cycles be, whats normal at idle ,under throttle and whats bad. Its all new to me so go slow. What else should I...

www.svtperformance.com

 

[olympic]

Yes 0.50 means 100% duty cycle. Check if the fuel filter is plugged. If not then it could be something inside the tank like the fuel pump, a plugged sock or a leak between the pump and hat.

 

[speed1st]

I have a new fuel filter on it. Only mods I have is cold air. Exhaust and tune. Thanks for response!! I’m going to take the pump out and see what it looks like this weekend.

 

[01yellercobra]

What's the pressure drop across the injectors reading?

 

[speed1st]

What's the pressure drop across the injectors reading?

Between 38-40 at idle. And WOT it drops to 14-15 psi

 

[speed1st]

Yes 0.50 means 100% duty cycle. Check if the fuel filter is plugged. If not then it could be something inside the tank like the fuel pump, a plugged sock or a leak between the pump and hat.

Thanks. I’m going to check it today.

 

[speed1st]

So I took the pump out. Changed the filter on the pump. And went ahead and changed the fuel filter again. Also have a new fuel pressure sensor on it. Now my FPDC is at .50. And about every 10 seconds drops to around .23 for about 2 or 3 seconds. fuel pressure drop is around 25.00 and drops to 10.00 to 15.00 just barely touching the gas. I bit the bullet and just ordered a new pump. Pretty sure that’s what it is. I’ll update after I replace it. Should have it by Wednesday.

 

[speed1st]

Update. Replaced the whole pump. Cars a beast! Definitely fixed the problem. My FPDC is running 0.17 at idle. And FUEL PRESSURE ACROSS INJECTORS is a steady 39.00. WOT FPDC is running 0.36. Remember this is with a SCT x4. So it’s running perfectly!!!! Thanks for all your help guys.

 

[oscarigz]

Good to see your issue was fixed. What pumps did you end up going with?

 

[speed1st]

OEM. Works great! Woke the car up! Tan a 8.54@84mph in the eighth!! Beyond happy!!