losing fuel pressure overnight ?

[Tractorat]

had the lose prime overnight situation w/mine years back. Ended up being pin hole in the metal supply line that leaves the top of the tank module, went with draw straw = fixed

The loss of prime issue seems to have healed itself at least for now. Im going to let it sit for a couple of days without trying to start it and see if it comes back.

 

[Tinmanroy]

I've just returned to TDR. Missed a few years. I bought my 2002 new. Still have it, Gonna keep it similar problem. FASS system /new. Second one. Now if it sets more than one day. I have to bump it at least THREE times , then she fired right up. If front lower than rear, now problem! Never had problem with first system. FASS says there's now check valve, local Mech says their is?? He said that he put one in. No change. I don't know what to do. It's frustrating having to bump several times if it sets several days. It cycles for 20+ seconds each time. I have a good gauge, reads good and runs great except for this. FASS says I can send pump back, but I'll be charged if they can't find any problem. PERPLEXED in PA. Roy

 

[DavidC]

Oh boy, here we go again.
If you bump the starter do you have almost instant pressure ?. Can you hear the Fass running instantly ?

Dave

 

[Tractorat]

I went back thru my records to see if I could find what the problem was when I started this thread. I think it ended up just fixing itself. Well, I started having a similar problem a few months ago. Same symptoms. Turned out to be batteries. The first time it happened when I first started this thread, Im thinking that maybe they were low from not driving the truck enough to charge the batt. This last time I got new batts and the problem went away.

 

[Tinmanroy]

Oh boy, here we go again.
If you bump the starter do you have almost instant pressure ?. Can you hear the Fass running instantly ?

Dave

Ok, no instant pressure, yes , 20+ sec running. Pressure when she fire's up.

 

[Tinmanroy]

No pressure until she fire's up. Yes I hear it.
Roy

 

[Tinmanroy]

By the bye batteries are new. Thanks

 

[BoeingDiesel]

That is very unusual...you should see pressure coming up when the lift pump activates. You might consider replacing the check valve on the injection pump.

 

[Tinmanroy]

There is a check valve on injection pump??
Is it hard to get at and can I do it, or does it have to be taken out.
Only thing, as I stated, this didn't occur until I had new FASS put in,

 

[DavidC]

It is called a overflow valve. Easily removed/replaced. genosgarage.com has it along with sealing washers. When I changed mine that is where the parts came from. When I removed the valve I blew backwards thru it and it leaked air showing it was faulty as it is suppose to open at 14 + psi. The valve comes with the washer but you may want to get some banjo bolt sealing washers as it is good to have some on hand. Are you still using the stock filter ?, I have seen reports that they sometimes do not seal enough and let air in the system. Check all line banjo bolts to make sure they are tight. Be careful as they are brass and can shear off. It can get very frustrating trying to solve this as there are numerous connection's and components. I have seen it go as far as the o rings on the injector tubes. Also check the return tee on the back of the block for wetness. Reports of the fass plastic ball check valve acquiring a groove and leaking by, pin holes in any of the lines either from age or weather conditions. Are you saying your pressure is 20 + ?.

Dave

 

[DavidC]

There is a check valve on injection pump??
Is it hard to get at and can I do it, or does it have to be taken out.
Only thing, as I stated, this didn't occur until I had new FASS put in,

I just noticed this. Maybe your pressure is to high ?. Or look closely at all lines etc. around that work area.

 

[Tinmanroy]

Thanks for the detailed description to follow. Are their any video's to follow ? I will check all joints. I did have all fuel lines replaced.
I just went to check starting truck, has sat for two days. I had primed FASS 7 times , pressure at gauge, cranked motor 6 seconds, fired up, got 15 lbs at gauge. I did change gauge thinking it might have leak, west tech to a isspro for better accuracy? Any how it run great after it starts. Pump primed 20+ secs every time I bumped it??
Roy

 

[Tinmanroy]

Do you mean stock fuel system, if so, no it's bypassed. I can find no wetness any where along lines.

 

[DavidC]

Pressure sounds ok and since the problem was not there until Fass change I personally would be all over the work that was done. Do not know of a video the closest you may find is a 2nd gen injector install since the o rings and tubes need to be pulled when doing that but now I do not think your going that far.

Dave

 

[Tinmanroy]

What do you do when the installer declared it's right? And he did go over it??

 

[Tinmanroy]

Find a new mechanic?? That cost..
Roy

 

[Tinmanroy]

I recall from past post. When truck front down hill, no problem, when flat or front up hill, won't start until several bumps on FASS .?? Just wondering......

 

[DavidC]

Find a new mechanic?? That cost..
Roy

I can't answer that one for you. I do all of my own work 99% of the time. If it was fine before the work and now it is not so it is either the parts or the work performed unless a coincidence occurred.

Dave

 

[DavidC]

I recall from past post. When truck front down hill, no problem, when flat or front up hill, won't start until several bumps on FASS .?? Just wondering......

If the front is higher and a no start usually means air is leaking in causing the fuel to siphon in to the tank. Parking with the nose lower than the back seems to solve that issue for some.

 

[Tinmanroy]

It works that way up/down. I do do as much work myself as I can. Sometimes I just don't have the right tools. I think that I will aoproach mechanic again. This just has to go away. I dont like things that arent right. Thanks, if you or anyone has a brain storm. Please let me know. And I will let you know if I get the problem solved. Thanks,Roy