Kid with a truck

Hi, my 5.4 runs and idles great but if I let it sit warm for an hour or two it requires extended cranking to start but helps to throttle it.

I cleaned the intake, checked the egr, changed fuel filter and injectors. whats left?

thanks im kind of stumped on where to go next with this problem

RLXXI

Hook up a fuel pressure gauge to see if pressure is bleeding down while it sits.

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Kid with a truck

If I have new injectors and the pressure does bleed off when I test it would that be a bad fuel pump?

RLXXI

That or a bad pressure regulator. Need to block off the fuel return line to see if it still bleeds down, if it don't then it's a bad regulator. If it does bleed down, bad pump check valve.

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Kid with a truck

ok sounds good. Im not sure if autozone is open tomorrow or not for thanksgiving. where is the return line and do I crimp it or what? thanks

RLXXI

Special tool to block the line without damage. Had one when I worked at the dealer, I'm pretty sure a good quality fuel pressure test kit will have one. May need to go to snapon.com

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Kid with a truck

I looked up the pressure regulator and its about $50 and a pump is $40 for just the pump. cant seem to find a pump check valve on rockauto. Ill check out the autozone test kit.

think this is definitely a fuel related issue and not a leak somewhere?

RLXXI

That $40 pump will give you headaches you don't want. Ford fuel pumps have the check valve built into them. Not cheap by any definition but worth the expense.

Without putting my hands on the truck all I can do is speculate what might be wrong with it.

I have 30+ years in the field and thousands of hours of training and none of it is worth a damn over the net.

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Kid with a truck

So your saying replacing the entire fuel pump assembly is way easier? And tonight it sat 3 hrs after getting hot and I cranked the throttle and backed off while cranking and it started much better than it does by just cranking normally. So that would have to be a fuel related issue. The part I don't understand is it runs great after its started. It idles smooth as can be and I'm running a straight pipe instead of the muffler