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Longer cranking...


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Ah ok, well that makes sense. I'm looking to eventually add a bigger turbo/inj/tuner and all that so that's why I wanting to hold off on injectors until I decided what exact power upgrades I wanted to go with so I could match everything up right ya know?

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So just something I noticed that I wanted to bring up here so see if you guys have the same thing happen.

 

Since I've been dealing with this leak I've been parking nose down in my driveway to avoid the harder starting until I get parts in and I noticed this morning that when I park nose down, when I turn my key and get the WTS light, my lift pump doesn't prime like it does when parked uphill. It's not much of a prime, just a quick buzz and that's it. But now parked downhill it won't prime at all but the truck fires up almost instantly.

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I can't help too much since I don't have an electric pump anymore, but that certainly doesn't sound right to me. My understanding is that the ecm triggers that at every key on just incase there is a leak, unless the key was just cycled. Unless it has a pressure sensor that it can tell how much pressure there is, and being downhill keeps a good bit off pressure in the line. But I certainly don't know of any such thing and I don't think there is. The thing is, there is no need for the system to re-prime after the truck has been shut off, if there are no leaks, air or otherwise. My Fuel Boss can't prime like that because it's engine driven and I have no issues with starting. My old FASS used to do it though, unless I cycled the key on and off very quickly. Maybe the FSM can tell you more? Sorry I can't be off more help, but I figure something was better than nothing and no one else answered yet lol

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Hey any input is good input!

 

I'm not sure if there is some sort of pressure sensor built into the system that tells the lift pump to run for a split second or not. I'm going to see if I can find anything. Other then that though I couldn't think of any other reasonable explanation.

 

What's weird is that the truck starts almost instantly while parked nose down over night and any time during the day. I can typically leave my truck parked 6-8 hours or more at work and walk out and she'll fire right up, no problems.

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There is no pressure sensor and when you shut the truck off the pressures bleeds off very quickly. 

When you park nose up it just magnifies a small leak since your fuel tank is now way below the rest of your fuel system. When you are level and especially nose down now you are getting more level and in the case of nose down the tank is above everything. It is just means mean ole mr. gravity at work pulling your fuel to the tank

As far as it not priming while nose down, i dont have a clue. Mine primes no matter what position I am in.

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Cool, that's what I thought.

 

I'll have to listen more closely to see if I can hear it all the time, or just at certain times.

 

Either way I'm not too worried about it because the truck starts fine and I have rock solid pressure at 18psi almost all the time, no matter WOT or idle.

Edited by notlimah
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***PROBLEM SOLVED***

 

So ended up getting this issue fixed!! Turns out the return line JIC fitting on my FASS was just slightly loose. I only turned it maybe an 1/8th of a turn and it has cured my longer cranking issues when parked uphill over night. Subsequently, it seems to have been causing me issues with erratic fuel pressure readings link HERE to that thread. Needless to say, I tightened that fitting up and it took a little bit of driving for the air to work itself out of the lines, so you have to be a bit patient with it.

 

Anyways, just wanted to pass along for future readers what ultimately fixed my issue.

 

I also found a cheaper source for the grommets that go into the TEE from Geno's. Links HERE part number is 3905351 from Cummins.

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  • 1 month later...

Ok so I potentially have this problem resurfacing itself. Here's what I've noticed...

 

Typically in the morning, on my first KEY ON where I'll get the lift pumps initial surge, it'll bump fuel pressure to about 4-5psi then slowly drop back down. Today after having the truck parked uphill for a couple days without starting, the truck only bumped to 2-3psi. Went to crank it like I normally do and the longer cranking was back. When I let off the starter it primed the system and I saw 18psi on my gauge so I turned the key again and it fired right up.

 

I dove back under the truck real quick immediately thinking it was the return line fitting on the FASS since that's what fixed it before and was able to crank it down about a 1/4 turn or so.

 

My question is, could the fitting be working itself loose? Or is it more plausible that I didn't tightened it down as much as I could've last go around? I'm going to put a sharpie mark on the two fittings to see if it's actually backing off. If so I'll need to replace the fitting. If not then it's back on the hunt for a fuel leak. :cry:

 

Any other thoughts on what could be causing this?

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I'm sure you've checked the back of the head and the metal return lines.....

 

It shouldn't be backing off, but it is a tapered fitting (if I'm remembering correctly) keep that sucker pretty tight! You may need some sealant on the threads as well.

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Yea I've replaced the O-rings at the back of the head and confirmed it was tightened down then. I believe the JIC fittings are tapered, but from what I've been told I don't need any sealant on a JIC fitting. Would it be ok if I put some Loctite 542 on the threads as well? I'll double check that it's as tight as I can get it later tonight.

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Just now, notlimah said:

Yea I've replaced the O-rings at the back of the head and confirmed it was tightened down then. I believe the JIC fittings are tapered, but from what I've been told I don't need any sealant on a JIC fitting. Would it be ok if I put some Loctite 542 on the threads as well? I'll double check that it's as tight as I can get it later tonight.

NO!! The tapered surface is what makes the connection sealed, so there's no need and no point.

 

What about where the fittings thread into the pump?

 

What about the rubbers on the return line from the VP and the back of the head to the T?

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52 minutes ago, TFaoro said:

NO!! The tapered surface is what makes the connection sealed, so there's no need and no point.

 

What about where the fittings thread into the pump?

 

What about the rubbers on the return line from the VP and the back of the head to the T?

 

Cool, that's what I thought. I'll see if just tightening it up like I did will fix it, and I'll also monitor to see if it is actually backing itself off. Are you talking about fitting into the VP or into the FASS? I'm going to go through and double check all of those fitting though. I used Loctite on all NON-JIC fittings, I'm starting to second guess on if I used enough or not.

 

I have the grommets to replace the 3 fittings at the T but I didn't install them because I thought I fixed the problem. After tightening everything down, if the problem still persists I'll install those.

 

14 minutes ago, CSM said:

If a flare style fitting leaks the sealing surface is dirty or damaged.  Damage can include surface inconsistencies or cracks.  

 

I hope I don't need to go as far as taking all the fittings off to clean, re-Loctite and install again but if I do, I'll double check all those things.

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IMO, jic/flare fittings shouldn't need loctite.  Not worth the effort or pain and if the loctite gets in on the sealing surface it could cause a leak. 

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