Air in fuel system?

[SHOTZY]

Well she sounded good for about 30 min. Got home and tried to fire it up and I was back to square 1. Fires up and shut off immediately. If I keep firing it, it progressively gets better and will start and stay running. It will shutter every now and again sometimes stalling. Threw 0089 fuel pressure valve performance. Will air in the system cause this? I also did the IP mod as well as the acutuator during the build. Also set for 8 months.(bad fuel)?Combo of these?

 

[LB7Diesel]

This is what we found lastnight. The Fuel PSI jumps to 12K at idle due to cp3 mod=P0089easy fix.

During logging at on frame Fuel flow rate drops to zero and then quickly rebounds to 96. Shortly after that it would die. Not sure what would be cutting fuel??

After each crank the truck would run longer and longer, finaly got it to where it would idle for 20 min. Once the engine get's cold it's back to having to keep starting it to get it to idle for any period of time.

It seems like it's getting air somewhere, but there are no fuel leaks running the lift pump when off. No codes other than the 0089. Any Ideas?

 

[x MadMAX DIESEL]

You may have a hair line crack on the fuel filter housing.... Just enough to get a vaccum and suck in air, but not leak.

If thats the case it may be about 15 cranking even after the filter is primed.

Does it have a lift pump?v Hook up a filled pressure gauge to the fuel lines. They should hold pressue for a good while once the truck is shut off


Starting and dying is a sign of a very dirty fuel filter

 

[SHOTZY]

The filter is new and so is the motor.

 

[Burn Down]

Are you sure the lift pump is not going out? Do you have a gauge on the supply side to the cp3? I'm not sure if the 1792 is flow through design or not?

 

[SHOTZY]

15 psi going into IP. I think I need to turn this into a 911 post because if I don't get this thing finished my wife is gonna burn it to the ground with me in it.

 

[sweetdiesel]

If the lift pump is pressured up the fuel system to 15 and you leave it for a bit and it doesn't leak off I would assume the regulator is sticking
thhe stock setup is vaccum so the lift pump should eliminate that problom IMO
no chaance you got debri in the fuel lines while the motor was out?

Log act vs DES rail and current

 

[SHOTZY]

Will check to see if it holds tonight. Will also do some more logging. When I got home yesterday the first thing I did was crack the bleeder screw and pushed the primer down. Fuel came out immediately. If my thinking is right, this should eliminate everything pre filter? I'm thinking it's sucking air on the back side of the IP where the mod was done. Joey has a stock housing (not sure if thats the right terminology) i'm gonna throw in to see.Running out of ideas here. The next step will be to run a hose into a 5 gallon bucket of fresh fuel.

 

[LarryJewell]

15 psi going into IP. I think I need to turn this into a 911 post because if I don't get this thing finished my wife is gonna burn it to the ground with me in it.

15 psi is a little too much pressure, can you back it down to 8-9 psi

 

[SHOTZY]

I've always run that much. Think there might be a hole new issue here. It runs perfect once it gets heat in the motor.(After cranking forever) Could this be the glow plugs?

 

[sweetdiesel]

Good chance it will throw codes if glowplugs are not funtioning

you can use a test light on the end of the glow plug to determine if they are working

I would be temted to pull the gp and crank the truck over to make sure you don't have a hung injector this will make for hard starting

I start my truck without plugs and it only takes a few cranks

 

[sweetdiesel]

Are you certain the cp3 is not leaking?

 

[SHOTZY]

Glow plugs are working. Not 100 percent on the leaking. I"ve looked at every possible connection no fuel found. Is it possible to not have a leak and still suck air?

 

[LB7Diesel]

I'm stumped on this one myself. The truck runs flawless when it get's some heat in it. No glow plug codes either. One thing he did find is that the cp3 feed line is getting sucked shut. Turn the lift pump on and it opens back up.

 

[stacks04]

Glow plugs are working. Not 100 percent on the leaking. I"ve looked at every possible connection no fuel found. Is it possible to not have a leak and still suck air?

it is very possible to have a vacuum leak and not have visible signs of external fuel leaks. your lift pump should be taking this variable out of the equation though. even past the filter housing. even if there was a vacuum leak beyond the filter to the cp3 i could see it being a bit cranky the first time before the lp pressured the system, but not after that. plus once the truck is started it should stay running, lp or not. unless your leak is that bad, which in that case it would also produce a visible fuel leak.

 

[SHOTZY]

My thinking is once the line is sucked shut it begins to suck air. The lp will correct this however, the air taken in still has to be purged through the ip, rails, and so forth causing the rough idle/stalling. Not sure here.

 

[skintback]

Whats the IP mod

Are the injectors stock

May have a injector or two returning to much fuel

I know when i had a 1792 the truck would run with it off just not very well not sure if it would suck the line closed

try and unplug the FPR and see what it does

 

[SHOTZY]

I drilled the two holes in the back of the pump and took the fpv apart and modded the piston.

 

[LB7Diesel]

Well after chasing our tails for ever. Steve finally found out what was causing his possesed truck to do what it was doing!



It was Electro-Magnetic-Interference coming from the wire that goes to the alternator to the Big Red 12V Junction Block. Evidently the factory wire that goes there is insulated, which he misplaced and replaced with a normal wire and, this was causing interference with the Eletrical System when plugged into the alternator.

He pulled that wire off and presto, run's smooth like baby ass.

So who's heard of this before?

 

[SHOTZY]

Lol. We spoke to soon. She still possesed as ever. Taken her to the dealer to to have Clint run the tec II. Hopefully this will help us.