Not trying to hijack jmul's original post but I think we both have the same problem. How much would a check valve restrict fuel pressure/flow. It has to some wouldn't it? Is this the same as the pressure relief valve mentioned above, and just replacing this fix the problem? I'm just trying to get to the bottom of this and having 2 restrictive devices in an already restrictive fuel system seems like bad mojo for the VP.

 

I had a similar problem a couple of years back, has any of you guys run out of fuel , or for any reason had to crack open the fuel injectors, I ran out of fuel because the tank was kinda low and I turned a corner too fast and the truck shutoff on me, when you run out you need to bleed the injectors which I am sure you already know, (sucks) anyway, I apparently screwed up the injector seals, when I put the lines back on and after that I had a pressure loss, which was extremely hard to diagnose, because if the truck was shut off recently it wouldn't take long to start, , maybe this could be of help,

 

pinching the line is a good idea, but i never know when its gonna be hard to start, (2500RAM) it never hits like its starting and don't start, if it hits it cranks-starts. i wonder about the fuel draining-leaking back, if this was happeining wouldnt it knock when it starts due to air in the system?? i have cleaned all the contacts etc with elec cleaner and put elec grease on them, that didnt help either. the reason for that is, i bought the truck used, it had a severe oil blowby, i had it overhauled by a machanic who knew what he was doing (by the way it was no way to start it without either at that time cause it was so hard to start) the engine had such a bad blowby it was blowing oil all over the entire underhood, i since cleaned it, thats why i cleaned all the contacts they were covered with oil. Ever ring in it was demolished? i did buy it cheap enough to compensate for a overhaul.
thanks for all the hlep, im gonna find it dont know when but im gonna find it!!!!

 

all i know is i had the problem for like a year plus.... and finally a 20 dollar check valve fixed it.. and i haven't had any problems since and i drive my truck full out for the most part. i've done several trips and hauled a 20,000 pound load.

 

i have been changing all kinds of stuff and troubleshooting EVERYTHING in the fuel system and alot on the electrical side... im going to give the check valve thing a shot!

 

I just put on a check valve, opens at 4psi, after the LP.

Three weeks ago, truck was hard to start in the morning only, then it got worse, to the point that after 20 min, it would just crank and crank, then start up and run great.

After I put on the valve, truck starts good up to about 2 hours, after that, it needs to crank a bit more, and overnight it is no better......

I just put on a new LP., I have new 3/8 line from tank to VP, a 2001 fuel filter housing, and now a check valve.

I took the check valve off the VP return line, it has a small hole in the side so there is no way it is responsible for maintaining prime...

I have searched and searched the forums, when someone figures this out, please post in the how to sticky....

Only thing left for me to check is return line, I might just replace all that tomoro, then the injectors, then the VP......

Or just deal the sucker in on a 08,,, I wish....

 

Does it seem strange that this hard start issue is happening a lot? I have the same issue.

 

well everyone has different mileage on their truck, so It must be a time related issue. I did notice on the return line, the flex part from the T behind the engine, to the hard line on the truck is made of stiff plastic, so perhaps it gets hard and brittle, then splits enough to let air in...

I am having a hard time understanding how a leak in the return line, after the injectors could cause this???

If the return line does not terminate in the bottom of the fuel tank under fuel, it will allow fuel to drain back all the time. and even if it did, it is still not a reliable method of maintaining a primed system. The overflow valve at the VP has a small hole in it so it can not maintain prime.

Where in the system is there a valve that would prevent air from the return line entering the system?? The cross over tubes flow into the return line, so the injectors must also be drained when not running??? I assume, as I do not understand how they work really...

I am leaning towards the VP itself..

 

atarter for shure

 

Just an update from an old post. My problems went away with a new VP. It finally threw the 216 code. no more hard starts

Good luck and I hope that's not your problem.

 

Seems a new return line has fixed my problem, for now....

I replaced the line from the overflow valve on the VP to the T at the back of the valve cover. $100 from the dealer....... I took the old one off, and plugged the bango end with a bolt, and put air pressure to the other end, put into a pail of water and sure enough a small pin hole where the line enters the bango fitting, just small enough to let air in... I supposed someone could re braze the line at the fitting, but mine was rusty at the bends and where it was clamped to the engine block behind the fuel filter, so I just replaced it.

Replaced last night, and truck started right up this morning like it should...