Hello all,

I am looking for some advise /help with a fuel pressure issue on my 2003 King Ranch S/C 5.4L 2V with D1SC Procharger.

I recently had twin Walbro 255 installed in-tank cause the in-line kept burning out. I had the feed line upgraded to a -8 braided and now the fuel pressure is sitting around 60 - 70 PSI at idle. I figured the fuel pressure regulator must have given up, so I replaced it, but it is still the same.

I am hoping someone with the same year can let me know what they did to cure this issue. I believe the 99 - 03 all had the same press and clip style regulators and I cannot find anyone that makes an aftermarket, adjustable FPR for this application.

I have two options that I can see:

1) find some '98 rails and purchase an adjustable FPR to fit.

2) purchase an aftermarket kit with rails, regulator et al (Aeromotive 14118)

Before I spend the $900+ they want for the Aeromotive kit, has anyone found a better, easier solution to this?

Thanks,

Mission

 

Are you using an fmu? If so, it is calibrated for 39 psi. I have never used an fmu, so I'm guessing here.........

 

Check the vacuum source to the regulator. Apply vacuum to the regulator to see if it lowers the pressure.

.

 

ONELOWF,

Thanks, No, an FMU is a bandaid fix. A good tune replaces it.

JMC,

Thanks, I will check to ensure it is producing vacuum. Didn't make a difference when I removed it to test, so that is likely the issue.

Thanks guys,

Mission

 

So, I checked the vacuum line to the Fuel Pressure Regulator and it is a steady 17 inch HG. What else would be the issue of high fuel pressure?

Thanks...

 

When you installed the duel fuel pumps did you kink the return line?

Regards

Jean Marc Chartier

 

JMC,

Thanks, I didn't do the installation. I had a local Ford Racing mechanic do it. I will crawl under to take a look. I talked to him about the issue being the return line after the feed line being upgraded. He assures me the return line is big enough stock since it is a "trickle" back.

Wouldn't it stall if there wasn't enough back flow?

Thanks,

Mission

 

Just a thought, since you already replaced the regulator. Are you sure your pressure gauge is accurate?

 

Thanks for the post.

Yeah, the fuel pressure guage is reading correctly. It also blows black smoke and runs crappy, so it is definitely running rich. It threw a code, but, of course I didn't write it down prior to reflashing the custom tune in hopes that would fix it. I am going to check the return line then take it for a run to see if I can get it to throw the code again.

Thanks,

Mission

 

Well, I crawled under and took this picture. It seems to be crimped in one spot of the line.



Think that may cause the issue?

Thanks,

Mission

 

If that's on the return side, then yes it looks pretty flat and would be restricting the fuel getting back to the tank.

 

Well, after pulling the return line and running it, it is still at 70 PSI.

 

Ask your installer which pump he used. A GSS340 pump is a 255 L/Hr high pressure pump.

Regards

Jean Marc Chartier

 

JMC,

It's the dual pump Walbro. I believe (don't quote me) it is the LFP-1198 kit. It is back in getting the return line replaced and I figured I might as well have the rails replaced with an adjustable regulator. I am getting plenty of pressure, so I believe the stock regulator is just not able to perform properly.

I am having it dyno'd immediately afterwards, so I will let you know how it goes.