LB7: Low rail pressure

[C-Power]

ok so i just did the injectors and now my truck wont freakin start,

i've primed alot, so today my dad hooked his scanner on and it said my rail pressure was only 250psi, so i dont know where to look or how to even go about tryin to figure out why,

 

[Burn Down]

Either it's not primed yet, or you have a fuel leak under the valve cover. Are you sure it's primed?

 

[MaxPowerLB7]

Maybe try cracking an injector to bleed off a little air.

 

[stacks04]

are you sure its primed. also has fuel? these take a little cranking to get fired up when that much air has been introduced to the system also. if there is all fuel coming out of the bleeder then crank it for a bit.

 

[C-Power]

yeah, i've got tons of fuel into my filter and it took forever to get fuel over to my driver side rail, but like i said, its still only got 250psi, we did crack the first injector line at the end of the rail on the driver side and bled it, i was in the truck crankin so im not sure if it got all the air out or not, my dad was under the hood,

 

[wdino73]

what's the crank rpm's I had that problem once, but a charger on the passenger batt, hope this helps, good luck, I'm sure we;ll get u going. unplug your regulator on the cp3 just to make sure your getting full command, I've talked to Guy about this in the past an sometimes you may need to crank the fuel lines going into the injector, It don't take much air in the lines to keep these littles darlings from running.

 

[REDHOSS02]

dont mean to be the burden of bad news but i had the same problem when my mechanic was changing my injectors and he kept cranking and cranking. then i noticed the the rear main seal was leaking. come to find out the fuel was getting into the crank case and started leaking out the rear main seal. when i pulled the drain plug to drain the oil it looked like dirty diesel. he ordered new injectors and replaced all eight again and that stopped that! so in other words check your oil for diesel!

 

[REDHOSS02]

when we ran the codes it said low fuel pressure and wouldnt start!

 

[Lb7KID]

dont mean to be the burden of bad news but i had the same problem when my mechanic was changing my injectors and he kept cranking and cranking. then i noticed the the rear main seal was leaking. come to find out the fuel was getting into the crank case and started leaking out the rear main seal. when i pulled the drain plug to drain the oil it looked like dirty diesel. he ordered new injectors and replaced all eight again and that stopped that! so in other words check your oil for diesel!

x2 on that i drained my oil/fuel there was 6 gallons of fluid in my oil pan i rip an injector 0 ring going in

 

[REDHOSS02]

lifes a b$$ch.

 

[C-Power]

no fuel in my oil,

alteast not yet, i have the P0093 code, Massive fuel leak,

one of my buddies is a GM tech at the local dealer, he is thier duramax guy so im gonna have him come over tomorrow

 

[C-Power]

ya ok good luck with that thought to many yrs working on diesels

talked to quite a few guys that had that problem, changed cups, did it right and no more pressure,

also just a side not IT RAN TODAY, last sat i broke my bleeder screw and didnt have the right size so i think i was suckin air in, but today i got the right size and cut it down to size and it worked great, and i had to prime w the key on, haha maybe i just got lucky but my buddy came over and we decided to try it, got it primed, cracked lines at the end of each rail rolled it till we got fuel and hit it w/ a bit of ether she lit right up,


down side to all that, it ran good for a couple minutes, i shut it down to finish it up, put the belt on all that little stuff, fired it again, this time just w/ rollin it over but it took a little longer then it should have, smoked a bit not bad, backed down the drive noticed the smoke was pretty heavy, kinda black haze, so i took off down the road and smoke stayed, got 1/2 mile stopped at a church to turn around and she was lopin hard, and had the pulling truck smoke lope thing goin on, so i headed home, and she kept smokin, if i took off it smoke black a decent amount, got it home, it was lopin real hard and smokin bad at idle, then it kinda started a knockin sound or a bad bad miss, so i shut her down, but while running i realized i had major blow-by, i mean major, tried a couple things nothin helped. tighted the injector lines i could get to went to try to restart it and nothin, wont start, hit it w/ ether she fires right up, idles great for a second then goes into that huge lope,

the kicker is there is no codes, not a single one, so i think the dealer will give me what i want out of it and im gonna off this truck and try somethin else,

but before i do that, tomorrow im tearin down the to the vavle so i can re-tighten my injector lines, b/c i seen 2 have a bit of fuel building on top of them, and im tearin out the middle so i can replace all the rubber lines

im not worried about the miss im more wondering about the blow by, b.c nothin i did has to do w/ the crank case, unless i blew a hole in a piston haha, but it idles good for a sec so thats not it,

 

[C-Power]

ok, so heres the update.........

tech II said #6 isnt even close to right, it was sticking open,

so the place i had test them Daves Diesel out of Angola, Indiana had one of thier guys that lives 10 min from my dads come out to look at it, and tear into it, he's the one that tested it w/ the tech II, well once in there he said it was b/c i had a loose injector hold down, sounds fishy, im goin there tomorrow mornin to figure out that injector and get new return line seals

 

[JoshH]

What was the Tech II saying to make them think the injector was stuck open? If you have an injector hold down loose, that could be the cause of blow by coming up around the injector, but it would probably lift the cup also. I wouldn't just tighten it back down if I were you.

 

[C-Power]

yeah true, that could have been the blow by problem, but im 99% sure i torqued it down, i did both sides the same way, they should have all been done 3 times, the first time kinda counts as 2 b/c i go till it clicks, then make sure it clicks again, then i went back through and did each one again, but idk i guess its possible, i was tryin to hurry,

ill see what i come up w/ :thumb:

 

[C-Power]

SHE RUNS! i changed out that injector #6,

actually it was kinda wierd haha, for 1 i felt like a pro!

2) i wasnt gonna change the cup b/c i figured it was seated or it would have pulled w/ the injector, boy was i wrong! i slid the new injector in and tapped it down into its spot, well i was tryin to teach a little kid some mechanic skills, and i was explaining stuff to him and i got to explain the ping you should hear when its seated right, so i rushed and forgot to put the hold down on haha, so i had to pry out the injector i just put in, and THE CUP CAME OUT! im kinda glad i did that now haha, that cup would have leaked for sure!

but i put a new cup in and went from there, only took about 3hrs of workin to change that injector and put the whole driver side back together! not bad i figured!

only sucky thing is i had to pick one of mine that were tested and werent as good as the other 4 of mine. so i have a bit of a haze again but im not worried about it, its mostly only noticable at night,

but my coolant system doesnt pressurize so that means my 5 cups i pulled was my coolant problem!