Installed mechanical lift pump but....

[niebs_22]

Now when the truck sits longer than 12-24 hrs I have to bleed the injectors to get it to start.

 

I have not seen fuel leaking anywhere. Once I bleed the injectors the truck starts and runs fine. If I try starting it even after sitting 1-6hrs it starts just fine. I have not had the stock lift pump engaged its purely running the mechanical lift pump right now. Has anyone had this issue?

 

1998.5. This was the first mod I did to it. I did a ISS pro gauge and big line kit to the vp44 at the same time as the mechanical LP.

Edited March 28, 2020 by niebs_22
Added truck year and other mods

[dripley]

Sounds like you an air leak causing the fuel system to loose prime. Sounds as if yours is a slow leak. It is possible you wont see any out ward leaking. Air can enter easier than fuel escapes. If you have checked the supply dont firget the return lines. They can cause same issue. Next time it does it try running your stock lift pump for a cycle or 2. It has worked in the past for me while experiencing the same issue

[Gregturley]

@niebs_22 you have a leak somewhere or a bad pump. If you have a leak on the return side it may be very different to find. I and many others have went pure mechanical with no electric lift pump an have no starting problems. These pumps move more volume and pressure than any electric pump can. More RPM, more volume and pressure. They are more reliable than anything electric.

 What mechanical pump did you use? 

[dripley]

An air leak is just that. Makes no difference whether you have a mechanical or electric. The problem can affect both systems equally. I run an electric pump because thats what was available when I put mine on.

[Gregturley]

An air leak will definitely affect electric or mechanical in a bad way. All i was saying is that it is not normal with a mechanical only set up. There is a problem that needs to be fixed.

[Dieselfuture]

How's mechanical plumbed in, straight to tank, filters, etc, draw straw, or trying to suck fuel through electric pump in tank or anywhere else  

[dripley]

3 minutes ago, Gregturley said:

An air leak will definitely affect electric or mechanical in a bad way. All i was saying is that it is not normal with a mechanical only set up. There is a problem that needs to be fixed.

Definitely a problem that needs to be tixed for sure. Just saying the pump style makes no difference, thats all.

[Gregturley]

Good point @Dieselfuture i assumed it would have been plumbed correctly and not trying to draw thru an electric pump. That could cause issues.

[Dieselfuture]

3 minutes ago, Gregturley said:

Good point @Dieselfuture i assumed it would have been plumbed correctly and not trying to draw thru an electric pump. That could cause issues.

I find that we all assume alot and a lot of times people that may be just getting on board with this have no idea what's what, until we know facts it's all assumptions. This goes for anything in life, we all like to assume but usually we're off and sometimes hurt fillings without meaning it. Happens quite a bit at work too, someone assumes something and makes a decision then it's not easy to admit. I learned to listen over the years. Or at least I try to.

[niebs_22]

I went with the fuel boss from Glacier Diesel Power. Thus far pump seems awesome I just wish I could keep the truck running. Is their a trick to find an air leak? @dripley The Parker fittings I ran on the new fuel lines seem pretty snug.

 

Idle I get about 15ish psi and driving I get between 13 and 15. At 65 mph it's about 13.5. Does that seem sufficient?

 

The pump is hooked to the harmonizer bolts. The fuel lines run straight to the tank. I have a Hobbs switch as a fail safe with the electric stock LP but it's not necessary.

3 minutes ago, Dieselfuture said:

I find that we all assume alot and a lot of times people that may be just getting on board with this have no idea what's what, until we know facts it's all assumptions. This goes for anything in life, we all like to assume but usually we're off and sometimes hurt fillings without meaning it. Happens quite a bit at work too, someone assumes something and makes a decision then it's not easy to admit. I learned to listen over the years. Or at least I try to.

I believe everything is plummet correctly. I retraced the instructions three times. All of the valves are facing the right directions as well. I'll try to put a picture up of the pump. Could my vp44 possibly be bad?

[Dieselfuture]

2 minutes ago, niebs_22 said:

The fuel lines run straight to the tank.

How did you hook up to tank, factory quick connect or did you pull module out and modified it in any way

[Gregturley]

@niebs_22 driving pressure is low. Check your relief valve make sure you don't have any crap holding it open.

[Dieselfuture]

My basket I modified with draw straw 5

[Gregturley]

Mechanical pumps will typically increase pressure with rpm

[niebs_22]

I took off the inlet hose from the gas cap(forfot what it's called), cut an inch out and installed a return manifold then clamped off each end. @Dieselfuture

[Dieselfuture]

1 minute ago, niebs_22 said:

I took off the inlet hose from the gas cap(forfot what it's called), cut an inch out and installed a return manifold then clamped off each end. @Dieselfuture

that would be for return fuel if I'm thinking correctly 

[Gregturley]

I didn't drop my tank when i did mine. Just cut the plastic line off and went from there up. Didn't do anything with the basket and have 18psi all the time.

[niebs_22]

2 minutes ago, Dieselfuture said:

that would be for return fuel if I'm thinking correctly 

Yeah it's for the return. I didn't have to drop my tank at all.

https://photos.app.goo.gl/MM4MgwQ8kqARBikK7

[Dieselfuture]

Did you have problems before mechanical pump install

[niebs_22]

1 minute ago, Dieselfuture said:

Did you have problems before mechanical pump install

No. I had low fuel pressure. I bought the truck stock and put a gauge on it and saw it was pushing 2-6 psi. So last month i installed the new LP.

 

I'm new to the site not sure the best way to upload pictures so hopefully these links work.https://photos.app.goo.gl/uyuE9ctBw6fwn8Sz9