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, 20205 yr by niebs_22
Added truck year and other mods

I feel that to make it right, the entire fuel system needs to be done over, at this time it seems you did everything but the pick up from tank itself,  maybe where your problem is, but then again if you didn't have this problem before then it may not be in tank pick up. I'd go over everything you did to make sure no leaks. Suction is where you can have a leak and not see it as its vacuum there and not pressure. 

The way we tested AN hoses we made up for the drag car was cap off one end, put a low pressure gauge say 30 psi max in line with it and pressurize the hose. Let it set and watch the gauge. If it dropped it was leaking. Kind of anal but it works. Spray bottle with soapy water will pinpoint the leak. 

36 minutes ago, Gregturley said:

The way we tested AN hoses we made up for the drag car was cap off one end, put a low pressure gauge say 30 psi max in line with it and pressurize the hose. Let it set and watch the gauge. If it dropped it was leaking. Kind of anal but it works. Spray bottle with soapy water will pinpoint the leak. 

That's how we pressure test pipes too

Those are low numbers on fuel pressure for the mechanical pump. I think the problem is in the canister inside the tank. Clogged screens, which need to be removed, or sucking thru an old electric pump down in there. Don't forget to drill some holes in the bottom of the basket. You know even if you showed no problems the fuel basket needs to be addressed. It's just built wrong from the factory.

Jag1 brings up a good point. If you didn't have a problem before, your intake pump if you had one used to push fuel so line was under pressure, now you're sucking it from front so the entire line is under vacuum. Can easily have a leak someplace in tank fittings, ether way if you redo the basket it will be for the better. Or you can do a regular draw straw as long as it's done the right way you should be fine. 

Also try with a full tank of fuel, see if you still have same issues. 

Edited March 29, 20205 yr by JAG1

That basket does not have any screens in it. Its the same basket my in tank pump came in. Matter of fact it has the red flapper in it that the pump pumped fuel over. The fuel pumped over it opened the flap and supposedly pull in additional fuel. At least per the AD intructions that came with mine.

@niebs_22 what are the 3 lines into the bottom of the basket? Mine has 3, engine return, pump return, and fuel pick up. Yours does too but I believe you said your pump return was in the filler neck. And did yours have the intank pump in it?

 

I cant for tgd life of me remember what the 3rd black is on mine. There is nothing to connect it to on the top

 

 

Here is mine unmolested then taken apart. Dont have one of the finished product. There are screens on the in tank pump on the right side and an outlet on the left to blow the red flapper open. I removed the flapper.

 

Both @JAG1 and @Dieselfuture bring up valid points. The big one in my mind is if it was not doing it before it most likely has to be something that was installed or disturbed duriing the mod.

Looks like I need to pay for a membership. I used up my 5 posts yesterday.

 

Anyway, I got under the truck last night. I drove it enough to see if a could find a leak. I actually found a leak coming out of the check valve that I installed. It's on the fuel line that runs up to the stock lift pump. I am guessing that is what's causing it to lose prime. When I installed it I didn't put any thread tape on those pipe fittings...rookie mistake. I am going to take them off today and see if the thread tape makes the difference. The below link is of the check valve that I am referring too. I am going to add thread tape to the T fitting also, because I am sure without it's also causing a little bit of air to leak in. I didn't realize thread tape was necessary on all pipe fittings.

 

@dripley I never took my basket out. I cut out a piece of my filler neck and added a return manifold. The return line from the new mechanical pump runs to the return manifold.

 

https://photos.google.com/share/AF1QipMqfkEXO22u8XYE6Eabq7W7jfyFtKMej30JlGtVn9QZw25IY30Nuld5HtipLBE0Qw?key=cWJ1ZGRrc2xlM25wV3pwYUNWNjY5V2c1T3dCbXJB

37 minutes ago, niebs_22 said:

I didn't realize thread tape was necessary on all pipe fittings.

Not always but if you're going to use it be very careful so non can make it to vp or injectors. You can get something in paste from Hardware store that has ptfe in it, should be good for gas/oil sealing. Usually says right on the bottle what it's good for.

3 minutes ago, Dieselfuture said:

Not always but if you're going to use it be very careful so non can make it to vp or injectors. You can get something in paste from Hardware store that has ptfe in it, should be good for gas/oil sealing. Usually says right on the bottle what it's good for.

Always apply the paste to the male fitting so it does not get pushed into the area of flow. Use light coating. I like the thread tape better and always keep it away from the tip on the male fitting. Only apply it to the upper portion of the threads.. When applying the thread tape you place the fitting in your left hand and with your right you run the tape over the fitting, not under. This will insure proper application or correct direction on the threads.

That tee in your pic is not pipe thread. Its JIC. Its a flare fitting. They seal with a metal to metal fit. Do not use tape or paste on them. If they are leaking they are not tight enough, cracked, something.

 Don't listen to anyone who says use sealer of any kind on them, they are wrong. They do not seal through the threads.

Edited March 29, 20205 yr by Gregturley

1 hour ago, niebs_22 said:

I never took my basket out. I cut out a piece of my filler neck and added a return manifold. The return line from the new mechanical pump runs to the return manifold.

Well double dumb *** on me. Those are @Dieselfuture's pics. Did you just reuse the original pick up then?

58 minutes ago, JAG1 said:

Always apply the paste to the male fitting so it does not get pushed into the area of flow. Use light coating. I like the thread tape better and always keep it away from the tip on the male fitting. Only apply it to the upper portion of the threads.. When applying the thread tape you place the fitting in your left hand and with your right you run the tape over the fitting, not under. This will insure proper application or correct direction on the threads.

Good idea. Thanks, @JAG1 I would have covered the whole fitting. Thanks for the tip.

 

@Gregturley ah, I didn't know that. Thanks! I will only use it on the check valve because those I know are not JIC.

@niebs_22 use paste or tape on anything with a pipe thread. Anything with a flare seals metal to metal. And i guess technically i lied. There are special sealants to use with JIC but thats typically for worn out fittings or extreme pressure situations. But never paste or tape and its not something the average person would have in their garage.

 What check valve are you talking about? If its the pressure valve that came with the fuel boss those should be JIC also.

 You can do a Google search on JIC vs AN fittings and learn a lot of good info.

5 minutes ago, Gregturley said:

@niebs_22 use paste or tape on anything with a pipe thread. Anything with a flare seals metal to metal. And i guess technically i lied. There are special sealants to use with JIC but thats typically for worn out fittings or extreme pressure situations. But never paste or tape and its not something the average person would have in their garage.

 What check valve are you talking about? If its the pressure valve that came with the fuel boss those should be JIC also.

 You can do a Google search on JIC vs AN fittings and learn a lot of good info.

It's the check valve leading to the stock lift pump. It's in the link

 

https://photos.app.goo.gl/ChcKdp2tcgr6ey279

Ok didn't see that pic before and i eliminated my electric pump so I didn't use that part. I think you're correct though that looks to be pipe fittings. 

Once you get your bugs out of your set up i think you'll really like it. Just be careful not to over tighten the belt. It runs loose to the point you will think its going to go flying off.

Agree with other posts here, I think you have a very small leak somewhere. I suspect on the suction side, but still double check all fittings on the pressure side such as the Big line kit fittings & adapter for the VP-44 inlet. (Make sure you used the cummins sealing washer that came with the kit (don't over tighten)). Also, on the suction side, check the hose clamp for the factory dorman connector to the stock electric fuel pump. And yea, double check that JIC Tee that sends fuel up to your factory elec pump and the inline check valve between that Tee and the factory elec pump. (check the banjo on the elec fuel pump discharge as well)  Additionally, wouldn't hurt to remove both JIC to pipe adapters from the fuel boss pump, apply thread tape or sealant (and as @JAG1 mentioned, apply tape or sealant on the male threads, away from the end so nothing foreign in ends up in your fuel system) and re-install the fittings.

Also try to rule out leaks on the suction side such as where the parker hose slips on to the existing hard line from the tank. Hose clamp tight? Just for the hell of it, get a mirror and inspect that hard line all the way back to the tank. Look for any rust. The slightest pin leak or pin hole anywhere on the suction side could cause your issue.

 

Ok so I installed the same fuel boss and big line kit on my 02 3500, no issues. 

 

However had a  similar issue with a 1st gen 1990 w250 5.9 cummins I owned years ago.  Same issue. Hard to start after sitting for more than 12+ hours. Kicked my ***. I finally (after about a month)  found a very tiny pin hole on the suction supply line, hidden in an area up under the frame near the fuel tank. It was a small rust nodule bump, barely any fuel coming out of it, not even enough to drip, just a tiny wet spot. (and as @dripley mentioned, air shall enter easier than fuel escapes)  I cut the entire line out and ran a rubber fuel hose all the way to the tank. Issue solved. 

 

I hope this helps. Keep us posted.

 

 

Edited March 30, 20205 yr by Ironforger

2 hours ago, Ironforger said:

Agree with other posts here, I think you have a very small leak somewhere. I suspect on the suction side, but still double check all fittings on the pressure side such as the Big line kit fittings & adapter for the VP-44 inlet. (Make sure you used the cummins sealing washer that came with the kit (don't over tighten)). Also, on the suction side, check the hose clamp for the factory dorman connector to the stock electric fuel pump. And yea, double check that JIC Tee that sends fuel up to your factory elec pump and the inline check valve between that Tee and the factory elec pump. (check the banjo on the elec fuel pump discharge as well)  Additionally, wouldn't hurt to remove both JIC to pipe adapters from the fuel boss pump, apply thread tape or sealant (and as @JAG1 mentioned, apply tape or sealant on the male threads, away from the end so nothing foreign in ends up in your fuel system) and re-install the fittings.

Also try to rule out leaks on the suction side such as where the parker hose slips on to the existing hard line from the tank. Hose clamp tight? Just for the hell of it, get a mirror and inspect that hard line all the way back to the tank. Look for any rust. The slightest pin leak or pin hole anywhere on the suction side could cause your issue.

 

Ok so I installed the same fuel boss and big line kit on my 02 3500, no issues. 

 

However had a  similar issue with a 1st gen 1990 w250 5.9 cummins I owned years ago.  Same issue. Hard to start after sitting for more than 12+ hours. Kicked my ***. I finally (after about a month)  found a very tiny pin hole on the suction supply line, hidden in an area up under the frame near the fuel tank. It was a small rust nodule bump, barely any fuel coming out of it, not even enough to drip, just a tiny wet spot. (and as @dripley mentioned, air shall enter easier than fuel escapes)  I cut the entire line out and ran a rubber fuel hose all the way to the tank. Issue solved. 

 

I hope this helps. Keep us posted.

 

 

Thanks for this, @Ironforger It does look like I have a very small leak on the inline check valve. Hopefully adding some tape helps resolve the issue. I will keep you all posted on what else I find. The leak was very small on that valve so I missed it when I first started this thread, It has been kicking my butt but I am glad to have found it now.

If your looking for a good liquid (paste) sealant for diesel try Rector Seal Blue.  You can usually find it at Home Depot, Lowes, ...

 

It is a non-hardening soft set sealant rated for fuel oil.

Edited April 7, 20205 yr by Joe_Pool
Spelling correction

Update-

 

So I fixed the leaks on the fuel lines. It was leaking around the check valve. I put some thread tape on and it resolved the issue. I noticed that I am having a very small amount of oil leaking around the Fuel Boss. I assume this means that I did not put enough RTV on the bolts or that I didn't tighten them down. So that's what I will be working on next.

 

I am still only getting about 15psi at idle which doesn't sound like a problem according to the manufacturer.

One question I have now is, I need to secure the fuel lines. What have you all done that has worked well. The obvious is to use zip ties but I am wondering if there is something better and more reliable.

 

Thanks

I used zip ties.