Chevy/GMC Duramax 04.5-05 LLY Discussion of Chevy and GMC Trucks with LLY Duramax Turbo Diesel Engines

low fuel rail pressure

Thread Tools
 
Search this Thread
 
Old Sep 8, 2012 | 04:10 PM
  #1  
duramaxguy's Avatar
Thread Starter
|
Newbie
Joined: Sep 2012
Posts: 3
Likes: 0
Default low fuel rail pressure

I got a 05 duramax won't start with out either took. It to dealer said 1,6,7,8 injectors were bad replaced them put new fuel pressure regulator on and injector return lines because I had a leak efi says I have 230 psi in my fuel rail any suggestions?
 
Reply
Old Sep 8, 2012 | 11:13 PM
  #2  
2004LB7's Avatar
Diesel Bomber
Joined: Dec 2010
Posts: 1,190
Likes: 113
From: Fool's Golden State
Default

turning over fast enough?
 
Reply
Old Sep 9, 2012 | 09:27 AM
  #3  
duramaxguy's Avatar
Thread Starter
|
Newbie
Joined: Sep 2012
Posts: 3
Likes: 0
Default

Turns over fine
 
Reply
Old Sep 9, 2012 | 10:07 AM
  #4  
2500HeavyDuty's Avatar
Super Moderator
Joined: Oct 2007
Posts: 14,872
Likes: 764
From: Houston, Tx
Default

bad cp3
 
Reply
Old Sep 9, 2012 | 11:19 AM
  #5  
duramaxguy's Avatar
Thread Starter
|
Newbie
Joined: Sep 2012
Posts: 3
Likes: 0
Default

Yes turning over fine
 
Reply
Old Oct 27, 2012 | 12:29 AM
  #6  
jban73's Avatar
Newbie
Joined: Oct 2012
Posts: 5
Likes: 0
Default

I agree: bad cp3. You need an injection pump, buddy. didn't they up the rail pressure with a scan tool to see if it held? You should always do that after replacing injectors. If the balance rates are all good, with new injectors, it should hold 160 MPa. If it doesn't, suspect the injection pump.
 
Reply
Old Oct 27, 2012 | 10:13 AM
  #7  
Jshannon02's Avatar
Newbie
Joined: Jan 2011
Posts: 8
Likes: 0
Default

Don't waste the money on a cp3! It will not fix your problem. When the cp3 pumps take a **** the readings are much lower. First check your oil for any fuel smell. You are looking for another bad injector. If the oil smells fine you need to pull the valve covers and carefully inspect all the injectors for any obvious defects. I just had a duramax in my shop with the same issue. The man had just taken it to another shop that told them the cp3 was bad. They replaced it and still got the exact 230psi fuel pressure reading. I got no codes with the scan tool. After beating my head against the wall I decided to pull the valve covers and simply do a visible inspection. I found that one of the injectors (#2) was actually broken right at the electrical connector. The wiring to the connector was still intact but it was allowing a fuel leak. Enough so it could not build enough pressure during cranking. You simply don't want to overlook this and end up wasting money on a cp3. PS..... NEVER USE EITHER ON A DIESEL!!!! At the very least it can melt glow plugs witch reach a temp of over 1300 degrees in less than 4 seconds. If that happens you end up tearing the engine apart to get the broken pieces out after you remove the damaged glow plugs. You should always disable the glow plug system then go to your local napa or what ever auto parts place and get a can of SILICONE SPRAY. It will start off of silicone spray and it lubricates so you don't have to worry about it washing down cylinder walls and creating a ring problem like you can commonly find with either. Good luck
 
Reply
Old Oct 27, 2012 | 03:26 PM
  #8  
2004LB7's Avatar
Diesel Bomber
Joined: Dec 2010
Posts: 1,190
Likes: 113
From: Fool's Golden State
Default

Silicon spray?!, I have always heard To use WD-40
 
Reply
Old Oct 27, 2012 | 04:18 PM
  #9  
Jshannon02's Avatar
Newbie
Joined: Jan 2011
Posts: 8
Likes: 0
Default

Yep, silicone spray. It starts off of it just fine and doesn't damage the engine. That is all my shop uses on diesels.
 
Reply
Old Nov 5, 2012 | 04:23 PM
  #10  
aj43az's Avatar
Newbie
Joined: Nov 2012
Posts: 4
Likes: 0
From: sedona, az
Default

help
along the same lines, i`ve replaced the filter housing bout 12 k back, just changed fuel filter, shimed the frpr valve twice, no fuel in oil, whats next?
have 96k on truck 04.5 lly

---AutoMerged DoublePost---

well took it to chevy, they said injection pump 96k on this truck
any suggestions as far as parts, or kits or?
thx
 

Last edited by aj43az; Nov 5, 2012 at 04:23 PM. Reason: Automerged Doublepost
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ctjkelley
Chevy/GMC 6.2L and 6.5L
7
Jun 3, 2015 06:01 AM
RatsMC
Chevy/GMC 6.2L and 6.5L
19
May 4, 2015 05:25 PM
robbyS
5.9 Liter CR Dodge Cummins 03-07
3
Apr 16, 2015 02:22 PM
moneypitk5
Chevy/GMC 6.2L and 6.5L
3
Feb 12, 2015 11:01 AM
vfizzano
12 Valve 2nd Gen Dodge Cummins 94-98
17
Oct 9, 2014 02:26 PM




All times are GMT -5. The time now is 10:31 AM.