Howdy All,

I just picked up a 2006 Silverado with a 6.6 Duramaz LBZ in it. It is my first diesel. Two days after I got it the idol became inconsistent after startup and the check engine light came on.

What happens is:
-truck starts and check engine light comes on
-truck is in limp mode
-shut truck down, wait a few minutes
-start up and truck is out of limp mode
-after 3-5 engine starts the check engine light goes out and the idol smooths out
-then two days later it starts over again

I used a code reader and it is telling me code P0088, if I clear the code the idol will smooth out. Two days later the code will come back.

Anyone know what I should be looking to replace to solve this? Could this be a vacuum leak, fuel pressure rail regulator, engine control module? I did replace the fuel filter, nothing changed.

Thanks
Cl Creek

 

Try doing a bottle test, so a search it on here it should show up

 

If I find fuel in the bottle what do I learn about what is going on? And if there is no fuel in the bottle what can I rule out?

 

Wait p088, different test. Sill me. Bottle test won't help you

 

possibly a bad Fuel pressure regulator?

 

P0088 code States: P0088 Fuel Rail Pressure Too High
I'd start with fuel rail pressure regulator, but it is very likely a vacuum leak somewhere, could also be some restriction to fuel delivery

Fastempo

 

I did try to see if I had a vacuum leak; not being able to find any damaged tubing and no codes in the computer to lead me in that direction I am assuming it is the regulator. So I went ahead and ordered a new Bosh regulator from Gillett Diesel; cheapest I could find at $150 everyone else wanted over $450. And I was able to download the instructions from All Data Pro (thanks to the guys in the shop at work!!).

I will change it out and hopefully problem solved. At first I was dreading this work, but now I am beginning to look forward to it. I haven't had the opportunity to work on a vehicle for about 10 years and I have never worked on a diesel. Hopefully me and my new truck become one this next week and the problem is cured by the new regulator.

 

It took several hours and some modified tools to fit into the small area cleared for changing the regulator but I replaced the fuel regulator and the problems have gone away. For anyone that has to do this, order a couple of T-25 Torx keys of different lengths before starting, you will need one long enough to reach around the regulator and then you will need one slightly shorter to fit onto the other two screws. It would be great if they made a set of Torx keys that could be cut to length (the same way you can cut a hey key - if I had known how hard it would be to access the three screws I would have had three hex screws ready to replace the torx).

I wonder if snap-on would have a tool for this...

 

I have replaced the fuel pressure regulator and the fuel rail pressure sensor but it keeps coming up with the same p0088 code. Truck is stuck in limp mode it's a 2007 chev 2500 hd 6.6 duramax