How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 29496
Experience:  GM Grand Master Technician 2007. 14 years experience.
10949255
Type Your GM Question Here...
GM Tech (Cam) is online now
A new question is answered every 9 seconds

I have a 06 gmc duramax that throws a low fuel rail pressure

Resolved Question:

I have a 06 gmc duramax that throws a low fuel rail pressure code when under a load. No not a filter prob. does this truck have an actual lift pump if so can i test it myself? i keep hearing horror stories about dealer incompetence.
Submitted: 5 years ago.
Category: GM
Expert:  GM Tech (Cam) replied 5 years ago.

GM Tech (Cam) :

Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.

GM Tech (Cam) :

NO, this does not have a lift pump.

GM Tech (Cam) :

THe injection pump pulls the fuel out of the tank.

GM Tech (Cam) :

There is a common issue with these engines. It is the fuel pressure relief valve. This valve is a small plug in the end of the drivers side fuel rail. When they get hot, the start to open a bit too soon and set this code. There is a cheap solution to this. A shim that will hold the pressure back. Here is a website that sells these shims. http://dmaxstore.com/index.php?main_page=product_info&products_id=93

Expert:  GM Tech (Cam) replied 5 years ago.

NO, this does not have a lift pump.


THe injection pump pulls the fuel out of the tank.


There is a common issue with these engines. It is the fuel pressure relief valve. This valve is a small plug in the end of the drivers side fuel rail. When they get hot, the start to open a bit too soon and set this code. There is a cheap solution to this. A shim that will hold the pressure back. Here is a website that sells these shims. http://dmaxstore.com/index.php?main_page=product_info&products_id=93

Customer: replied 5 years ago.
when the truck is under a load and you ask it for more power that is when they send this code. also i do have a tuner in this truck and if i have it turn up then it will throw this code with out a load but under hard acceleration. also the problem has gradually gotten worse over the course of the last six months. is this pressure relief valve shim an installation that is possible for someone with competent mechanical abilities without the use of expensive specialty tools. the truck has 138,000 miles on it.
Expert:  GM Tech (Cam) replied 5 years ago.
The shim is very easy to install and for the whole $15 it is, is well worth the time to try. It comes with directions but it goes into the end of the drivers side fuel rail.
Customer: replied 5 years ago.
I have been under the impression that the LB7 did not have a lift pump but the LBZ did? Is this accurate? My pickup is the 06 with the 350 factory horsepower engine NOT the 300 horsepower engine I believe it to be the LBZ is this correct? the vin for this truck is 1GTHK23D56F229268 if this is helpful in giving me any more diagnostic info. The code that it throws is P0087 I think. If the shim kit does not fix the problem what would your reccomendation be for further steps?
Expert:  GM Tech (Cam) replied 5 years ago.
None with the exception of the LLY in the vans have a lift pump.
YEs the D is the LBZ with 360 hp.
You shoud put the shim and and see. If not that then we may be looking at injectors or the injection pump.
GM Tech (Cam) and 3 other GM Specialists are ready to help you