Duramax Diesels Forum Truck of the Week
  #1  
Old 11-18-2011, 09:25 AM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default losing prime

Ok so first off I'm on the list for new injectors. Getting a little haze at idle. No fuel in oil or other problems. Did however have a leaky bleeder screw due to a crack. Pulled the filter head off today and put in new seals and new bleeder screw. Put it back in with a new filter and primed it. Got nice and firm and the truck fired right up and I let it run a few minutes.

Went to start the truck back up and nothing. So I put the test gauge on the test port and primed it back up. Started the truck and it holds positive pressure at idle but once shut down it bleeds off. It also bleeds off if you prime it and don't start it. I did open the drain plug in the wif for the first time ever. About to pull the inner fender and see if its leaking. Any other ideas?
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044
Reply With Quote
  #2  
Old 11-18-2011, 10:10 AM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default

Ok so I took the inn fender out. I can pump to my heart's content and the primer won't get very firm but no visible leaks anywhere.
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044
Reply With Quote
  #3  
Old 11-18-2011, 11:53 AM
Linden's Avatar
Linden Linden is offline
Sparkplugs FTL
 
Join Date: Dec 2009
Location: Florida
Truck: ccsb
Engine: LB7
Transmission: Automatic
Posts: 170

Default

i had similar issues it was the seals this would probably take care of this
http://www.merchant-automotive.com/d...ebuildkit.aspx

i bypassed mine and switched to a airdog 150
__________________
Reply With Quote
  #4  
Old 11-18-2011, 12:22 PM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default

It didn't start doing it until after I rebuilt the filter head. I've had it back out and ran through it again. Everything looked fine. Still no luck. A few pumps and it fires up and runs fine. Shut it down and wait about a minute and it won't fire. I can watch the pressure drop as soon as I shut it down.
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044
Reply With Quote
  #5  
Old 11-19-2011, 04:49 PM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default

Update. Lines running to and from filter head where cracked so I replaced them. Also got a known good filter head from a buddy who deleted his. Primer gets firm now. Truck fires up and runs, but still loses prime when shut down. Got a fuel cap and put a valve stem in it. Don't have a clue what it could be seeing as how it didn't start doing it until I took the filter head off last time. Also according to the dipstick I'm not making any oil.
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044

Last edited by CancerPipe; 11-19-2011 at 05:05 PM.
Reply With Quote
  #6  
Old 11-21-2011, 07:41 AM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default

Bump. Pushed some air in the tank. Couldn't find any leaks. Found something strange though. Pulled the truck into the garage and shut it off. Pulled the filter for the hell of it and its only half full.
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044
Reply With Quote
  #7  
Old 11-21-2011, 05:01 PM
Hole Shot's Avatar
Hole Shot Hole Shot is offline
Smoking LB7
 
Join Date: Feb 2010
Location: Quincy, Fl
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 129

Default

Does your lift pump work ?
__________________
EFI live Dsp 5 by S Phinney ,Exergy 40% over injectors
NOS,Suncoast stage 5 with 1056, modified intake horn,
PPE 150 lift pump, 5" Magnaflow, PPE Sleeves,
S&B intake, Shiver Diesel
Reply With Quote
  #8  
Old 11-21-2011, 05:53 PM
tyrat's Avatar
tyrat tyrat is offline
tdi
 
Join Date: Nov 2011
Location: Dyer,Indiana
Truck: RC/LB
Engine: LB7
Transmission: Automatic
Posts: 196

Default

i was gonna say fuel lines we had a dd that wouldnt hold prime had a hole in the lines and would collapse itselfs when given throttle
__________________
2007 cclb 4x4 340k miles built tranny
2001 cclb 2wd 260k forsale
2004 white silverado 2500hd 4X4 dmax 405k miles ec/lb forsale
2007 lbz white eclb 2wd 3500 325k miles

2005 silver golf tdi 164k. Forsale

2002 white silverado 2500hd cc/lb dmax 245k miles SOLD
2003 white dmax silverado 2500hd drw ec/lb 289k miles **SOLD**
2008 silverado rc utilitybox 2wd 2500hd 160k miles sold
2003 blue sierra 2500hd dmax 330k miles rc/lb stock *SOLD*
2006 lly white ccsb 4x4 2500hd 283k miles SOLD
2003 yellow sierra 2500hd rclb 2wd 181k miles sold
2006 eclb. Copper color 220k milesSold
Reply With Quote
  #9  
Old 11-22-2011, 06:35 AM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default

Twin pumps are running on one stator at the moment. Just enough for 5psi. I'm honestly tired of messing with it. Been trying to get it to take some air pressure for a couple days.
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044
Reply With Quote
  #10  
Old 11-23-2011, 03:28 PM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default

A friend of mine wasted the better part of the day helping me today. We've done everything either of us can think of. Did have a suggestion that it could be the high pressure relief in the rail. Can't find a leak what so ever. Won't run without the filter head/primer either.
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044
Reply With Quote
  #11  
Old 11-23-2011, 05:13 PM
bullfrogjohnson's Avatar
bullfrogjohnson bullfrogjohnson is offline
Big Girl!
 
Join Date: Nov 2006
Location: Locust, NC
Truck: 03 white ccsb lb7
Engine: 6.6 duramax
Transmission: Automatic
Posts: 4,980

Default

You need to bypass the lift pumps and get it running and recheck your pressures. Stock should see around 4-6 inHG of vacuum at idle and 10-12 inHG at 160mpa. You can also apply pressure on the return line and block of the supply and pressure check the system for leaks. The spec is 15 psi for pressure checking. Use a hand vacuum/pressure pump with a gauge (mighty vac). If you have a high vacuum at idle there is a restriction in the lines. Little to no vacuum, theres an air leak. You have to check the system at 160mpa also because your idle vacuum may be in spec but when you crank the rail pressure up it can lead you to your gremlins

You can also add a UV fuel dye in the tank and let it run for a bit. Then pressure check the system and use a UV light to help spot a small leak.

I worked on a truck that had the half full fuel filter issue and it ended up being trash in the tank and trash made it all the way up to the FICM inlet and clogged up in the banjo bolt and partially blocked the fuel supply.
__________________
Travis
03 CCSB lb7
06 2500hd ECLB 6.0 gasser

2010 Straight Diesel 2.8 Points Champion
special thanks:
B&B Pulling and Greene's Diesel Performance, Fully Spooled Motorsports, Johnboy, Simon, Ed, ProFab Performance, Hamilton Cams, Extreme Prejudice Racing, Ridge Runner Diesel
Reply With Quote
  #12  
Old 11-28-2011, 09:56 AM
CancerPipe's Avatar
CancerPipe CancerPipe is offline
Hotrodder
 
Join Date: Aug 2007
Location: Chattanooga, TN
Truck: CC/SB
Engine: LB7
Transmission: Automatic
Posts: 362
Default

Didn't get a chance to do anything this weekend. And can't seem to find my mightyvac. Went out to start the truck and move it so I could get my work truck out and it wouldn't start. Tried priming but never could get it to start. Primer didn't feel right it was firm, but never got hard and wouldn't go all the way down. Batteries are almost dead too, even though I drove the truck friday and saturday. 1.5 year old interstates.
__________________
04 LB7 CCSB 4x4

EFI Live OS:15189044
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -7. The time now is 08:00 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
vB.Sponsors