Fuel Pressure check valve???

[CityHick]

Hey guys,
Since converting my rig to EFI (3 years ago), I have noticed that when the rig sits for a week or more, the fuel lines seem to completely drain, and then they take forever to pressurize. This has been the same both when I ran external pumps and now with my in-tank pump.

Is there such a thing as a check valve to hold fuel pressure in the lines? I tend to think there must be. My other fuel injected vehicles can sit for months, and they fire at the first bump of the key. My Bronco... a week of not driving it and I've either got to cycle the pump with the key (repeatedly), or ground the test lead on the scanner connector and run the pump for a minute or so.

I don't think I've ever had another fuel injected vehicle that acts like this, and there must be a one-way check valve I can put inline somewhere... or I just deal with this minor annoyance. Once the fuel system primes again, the engine fires right up and runs like a champ.

[Efibroncoman]

Re: Fuel Pressure check valve???

Yes, there is a check valve inside the in-tank pump. You may also have a pin hole in the fuel hose near your pump too. I've seen that happen before.

[CityHick]

Re: Fuel Pressure check valve???

Thanks.
This acts the exact same as when I had external pumps, and it always has since the pump was new - but in this day and age that doesn't really mean much.
I did search a bit and found some aftermarket check valves that seem to fit this bill, but am curious if anybody here has experience with them.

Fuel lines are also new as of my conversion to an in-tank pump and I've not seen this get better or worse ever.

This is just something that's been bugging me for a while, and since I have driven the Bronco a bit lately with this nice weather, it is more fresh in mind now.

[ntsqd]

Re: Fuel Pressure check valve???

Inline check valves:
-6 AN http://www.summitracing.com/parts/aei-15106


1/4 NPTF http://www.summitracing.com/parts/crt-169-1002

[1968u15]

Re: Fuel Pressure check valve???

The fuel pressure regulator can cause this issue as well, whether it is leak at the diaphragm(out the vac. signal line to the intake manifold) or through a leaking valve (and back to the tank through the return line).If the diaphragm leaks the engine will generally run rich due to the extra fuel introduced to the intake manifold. But a leaking regulator valve may go undiagnosed for quite a while, especially if the pump has large volume at operating pressure. If you can block the return line and install a pressure gage on the pressure side then cycle the key the gage will hold max. pressure of the pump for quite a while . Indicating the check valve in the pump is ok. If the return line is then unblocked the gage should show between 30 and 40 psi on a stock system and hold it for a couple minutes. If it drops in a couple seconds that is your problem. On a hot motor the fuel will boil in the line until the line is nearly evacuated. Causing long crank times at the next start up.

[CityHick]

Re: Fuel Pressure check valve???

Thanks for the responses, guys. I wanted to investigate this more over the weekend, but as usual I ended up barely even looking at the Bronco. The fuel pressure regulator is going to be where I look next. I do sometimes notice that the exhaust smells a little rich but it never trips the CEL so it must not be too rich for too long. I feel like adding a check valve would be masking the true cause of the problem at this point (because the factory did not use one), and the fuel pressure regulator would be an easy place to start.

[1968u15]

Re: Fuel Pressure check valve???

I'm curious to know what you find. Also like Efibroncoman said the factory check valve is in the pump.

[blwngsket]

Re: Fuel Pressure check valve???

Mine doesn't act that way. And as some of you know. It sits for months without being started

[CityHick]

Re: Fuel Pressure check valve???

Alright fellas. I replaced the fuel pressure regulator a week and a half ago. Ran the rig for a while then parked it that day. Tonight it fired right up as if I drove it an hour ago.

Thanks for the input, I love an easy fix. My 46 year old bronco now officially starts and runs like my other two (modern) rides.

[1968u15]

Re: Fuel Pressure check valve???

Great, glad you got it sorted!

[CityHick]

Re: Fuel Pressure check valve???

Great, glad you got it sorted!

Yep me too. Now on to other minor annoyances (not fuel or engine related). It has been nice driving my rig around a bit this week. May start taking it to work once a week again soon. I need to keep it moving otherwise I tend to forget about it.