Realistic budget of a 2wd -4wd and goodies build

[Greg5OH]

saw two kinda loose connections on the return lines, repaired those, gave all the lines a tug test, seems good. replaced shrader valve, ran the e pump, purged air out of the filter head, same thing, crank crank crank, stopo, reglow for 5 seconds, crank crank takes off like air intrusion, then within a second settles into a normal smooth cold idle.
shut it off, within a minute go check the shrader valve with the pump off, hear a hiss of air. am i still getting drainback? If i recall correctly when I had my old mechanical pump, with the truck off i was still able to press the shrader and get a dribble of fuel out of it? it definitely starts like air intrusion..

 

[laserjock]

If you just leave the key on for a while and let the pump run then glow and crank is it better/worse/different? That would mitigate the air intrusion problem right?

 

[Greg5OH]

has no effect. let the e pump run for a minute before glowing and cranking. same exact sequence every time. What is consistent that afte ri start it, shut it down, i press the shrader, and no fuel comes out. turn e pump on, let it run a few seconds, pres sthe shrader slight air purge and then clean diesel flows out. try starting, same sequence.

 

[laserjock]

So you have a serious leak somewhere. Maybe a check valve somewhere is in order? Are you using the factory filter head?

 

[Greg5OH]

How serious? Its bone dry under there at all connections? Im thinking maybe its at the olives from filter head to pump..but it is dry there. Yea stock 7.3 filter head

 

[laserjock]

If it's draining back that fast, it would seem to me it's a pretty serious air leak. Air leaks a lot easier than fuel. I don't remember if the facet pumps have a check valve in them or not. When you did your senders, did you put the little duck bill thing on the return line? It's suppsed to slow it down.

 

[OLDBULL8]

Probable the olive at the IP is letting air in, it won't leak fuel, you can't purge the air out at the filter from the air in the IP, e-pump pushes fuel into filter, fuel pushes air up the hard line, thru the IP to the return lines, air has to go thru return lines back to tank, results is crank crank crank then start, roooooommmm. engine loves full fuel lines.

 

[Greg5OH]

I will go take apart that hard line and see whats up.
Whats interesting, when u shut the truck off, you hear a little "pick" sound every 2 seconds or so for a while then stops.. almost as though there is vacuum on the fuel line then it lets off, catches vacuum,lets off. I didnt feel anyrhing vibrate in the lines, none the less i will investigate.
But what i do wonder is, wouldnt the electric pump purge all the air out? Its epump to filter head, to ip, to return to tank? Doesnt matter how long i run the epump for still starts bad.

what also is evidence that something is causing a drain back is the ip drain goes into one side of the brass T, and all the injector drains go into the other side, and then its the one line going back to the tank..well i pulled that line off a week ago to re reoute it, and it was dry in there, no fuel dribbled out, meaning it all drained back from the filterhead onwards.

filter does remain full though.

 

[Greg5OH]

which siZe olive do i need on the filter to ip? Big ir small? These are both from Russ way back

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also, over the weekend finished the bumper, need to seam weld and paint it still! Looks so bad from the side though lol

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[LCAM-01XA]

Does your filter head have an air bleed port that's hooked to the return line? Ours has been plugged for years, haven't had a single airlock issue even when the fuel heater connector sprung a leak cause fuel simply had nowhere to drain off to.

As for glowplugs, ours starts at 11.9V before I hit the button, dropped down to 10.5V initially when the plugs started heating but quickly tapered up to 10.9V and stayed there for the remainder of the glow cycle. Which today was 10 seconds, didn't feel like burning them unnecessarily long when it's so hot outside the truck doesn't actually even need them to start...

The rhythmic ticking sound you hear could be exhaust manifolds cooling off, or the A/C system can sometimes produce something similar as well.

From my understanding on how the DB2 pump works fuel can still flow thru it even with the FSS shut off, the FSS simply closes fuel flow towards the high-pressure side of the thing. So the Carrier pump should in theory purge all the air that may be collecting in the IP feed line thru the pump's main body cavity and then out the top discharge port. Actually every single time we've had our IP open for fuel screw adjustment we've never had to reprime it afterwards, as long as the engine was hot and thus capable of near-instant start even tho the pump's main cavity was empty of fuel the high-pressure side still held plenty enough to start the engine, and the moment that happened the factory-style mechanical lift pump immediately purged all the air out the top port and down towards the tank, engine didn't even attempt to stumble due to ingesting some air in the high-pressure side of the IP.

 

[LCAM-01XA]

You need the smaller olive. The big one is for the 3/8" line between the mechanical lift pump and the filter head, the line between the filter head and the IP is 5/16".

 

[Greg5OH]

No ac system, its more of a deeper sound than exhaust manifolds, llus the truck is literally on for 3 seconds, they dont even yet warm to the touch.
Yes i have that line, i checked it again this morning, it is all tight.

If the e pump can flow through the whole ip, and out the return.. Dont get how were getting air in.. Ill check that hardline tomorrow morning..

 

[OLDBULL8]

If your filter head has this on it, it could let air in if it's defective, fuel pressure will keep it closed, without fuel pressure keeping it closed it could let air in, it's not necessary and can be removed and plugged off.
Above refers to the fitting on the right side in pic, that is actually for air bleeding by pushing in on the button.

 

[Greg5OH]

Yes i have the big ol trumpet on there. Is it just an npt plug that can be put in there? 3/8 or 1/2"? What do i plug itnoff woth?

Still doesnt answer how come the electric pump cant purge the air out? Or starts hard even after i manually purge the air from filter head as the pump is running?

 

[79jasper]

Should be 1/8 npt for the restriction sensor.
And yes, just a brass plug.
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