Fuel pump turning on early?

[emh87]

I've picked up my new mustang back in early 2015, and every time I get in, the fuel pump would only turn on when the clutch was pressed in. Now the second I open the door I can hear it kick on, like I already pressed the clutch in. It never did this till I let it sit for winter, the battery did die from sitting, and ever since I jumped the car it started doing this randomly. Sometimes it doesn't turn on until I press the clutch, and other times it's when I open the door. Also I noticed it seems like the car barely wants to start now randomly as well, like the battery is being drained, and I think it might be related. This is also random, but seems to be possibly happening when the fuel pump turns on prematurely too. Seems like maybe the fuel pump isn't always shutting off. The only thing I have done fuel pump related was add the vortech fuel pump booster. Thoughts?

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[TruBlue16]

Use a multimeter to see if there is a drain on the battery when the car is off. Also make sure the battery is not going bad.

[ame]

 

[paul123]

I've picked up my new mustang back in early 2015, and every time I get in, the fuel pump would only turn on when the clutch was pressed in. Now the second I open the door I can hear it kick on, like I already pressed the clutch in. It never did this till I let it sit for winter, the battery did die from sitting, and ever since I jumped the car it started doing this randomly. Sometimes it doesn't turn on until I press the clutch, and other times it's when I open the door. Also I noticed it seems like the car barely wants to start now randomly as well, like the battery is being drained, and I think it might be related. This is also random, but seems to be possibly happening when the fuel pump turns on prematurely too. Seems like maybe the fuel pump isn't always shutting off. The only thing I have done fuel pump related was add the vortech fuel pump booster. Thoughts?

sounds like you have gremlins :doh:

you probably should get a load test on that battery if you let it go to zero. Make sure its still good.

As for the fuel pump, how long does it stay on? I thought they just blipped to pressurize the system and then turned back off. Still, I don't think it should do that until you press the clutch and press the Start button.

 

[FordTechOne]

I've picked up my new mustang back in early 2015, and every time I get in, the fuel pump would only turn on when the clutch was pressed in. Now the second I open the door I can hear it kick on, like I already pressed the clutch in. It never did this till I let it sit for winter, the battery did die from sitting, and ever since I jumped the car it started doing this randomly. Sometimes it doesn't turn on until I press the clutch, and other times it's when I open the door. Also I noticed it seems like the car barely wants to start now randomly as well, like the battery is being drained, and I think it might be related. This is also random, but seems to be possibly happening when the fuel pump turns on prematurely too. Seems like maybe the fuel pump isn't always shutting off. The only thing I have done fuel pump related was add the vortech fuel pump booster. Thoughts?

How did you install the aftermarket fuel pump booster?

The fuel pump control module is commanded directly by the PCM via a Pulse Width Modulated (PWM) signal. If you spliced into any of the fuel pump circuits, you will affect how the fuel pump control module and fuel pump operate.

 

[emh87]

How did you install the aftermarket fuel pump booster?

The fuel pump control module is commanded directly by the PCM via a Pulse Width Modulated (PWM) signal. If you spliced into any of the fuel pump circuits, you will affect how the fuel pump control module and fuel pump operate.

The fuel pump booster was installed after the module, basically splicing into the wire right before the fuel pump.

 

[FordTechOne]

The fuel pump booster was installed after the module, basically splicing into the wire right before the fuel pump.

I'm guessing it's one of those voltage booster mods that splice into the fuel pump power circuit between the Fuel Pump Control Module and the fuel pump? How was it installed? Quick splices?

If it wasn't properly soldered in and heat shrinked, you will have added resistance in the circuit, which will the Fuel Pump Control Module will most likely detect. That can cause the Fuel Pump Control Module to flag a fault, which it will then transmit to the PCM via a pulse width modulated signal on the Fuel Pump Monitor (FPM) circuit. When the PCM receives the fault information, it will then set a pending or active DTC. Depending on the nature of the DTC and how often the fault is being detected, that will affect the operation of the entire system.

Even if the mod was properly soldered in and heat shrinked, it can still cause a fault to be set. This is due to the fact that the fuel pump control module is capable of monitoring the voltage and current flow to the fuel pump. If either is out of specification, it may set a fault.

 

[paul123]

The fuel pump booster was installed after the module, basically splicing into the wire right before the fuel pump.

when did this get installed? when did the problem start?

 

[emh87]

I'm guessing it's one of those voltage booster mods that splice into the fuel pump power circuit between the Fuel Pump Control Module and the fuel pump? How was it installed? Quick splices?

If it wasn't properly soldered in and heat shrinked, you will have added resistance in the circuit, which will the Fuel Pump Control Module will most likely detect. That can cause the Fuel Pump Control Module to flag a fault, which it will then transmit to the PCM via a pulse width modulated signal on the Fuel Pump Monitor (FPM) circuit. When the PCM receives the fault information, it will then set a pending or active DTC. Depending on the nature of the DTC and how often the fault is being detected, that will affect the operation of the entire system.

Even if the mod was properly soldered in and heat shrinked, it can still cause a fault to be set. This is due to the fact that the fuel pump control module is capable of monitoring the voltage and current flow to the fuel pump. If either is out of specification, it may set a fault.

It was installed using crimps, should I redo this using solder and heat shrink?

 

[paul123]

It was installed using crimps, should I redo this using solder and heat shrink?

is it normal to install this way ? can they power it on a dedicated circuit?

 

[paul123]

not sure if this is it, but this sure seems like a lot of power:

http://www.vortechsuperchargers.com/page.php?id=30184

Power Output: 600W - 17v at 35a typical (comparable to competing "40a" units)

 

[emh87]

not sure if this is it, but this sure seems like a lot of power:

http://www.vortechsuperchargers.com/page.php?id=30184

Power Output: 600W - 17v at 35a typical (comparable to competing "40a" units)

Yeah that's the one, it's the non-programmable one.

 

[paul123]

you might create a related thread over in the FI section. Ask what the recommendation is for wiring up this sort of thing. I am doubting you want to do a crimp for 600W gear

 

[emh87]

I had another somewhat related thread in the FI section, and it appears that I may have the fuel pump booster wired incorrectly. I will rewire tomorrow and test.

 

[FordTechOne]

I had another somewhat related thread in the FI section, and it appears that I may have the fuel pump booster wired incorrectly. I will rewire tomorrow and test.

Interesting...please let us know what you come up with.

 

[emh87]

So it was the fuel pump booster being wired wrong. All the issues I was having seem to be gone now.

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