Yup I'm going now to get it hooked up to a scanner. It's got to be a sensor not working rite

 

I was wondering if you had any update on your issue. I also have the same problem when I hook up my LQ horse trailer. Having hell trying to figure it out.

 

I had the same problem with my 2009. Pulled filter head apart and found it full of rubber fuel line. Removed fuel lines from steel line to engine and found it was coming apart.

 

I've got this same issue driving me crazy on one of our fleet trucks- 08 2500HD with the duramax. 156K miles. We installed the airdog system and did a full dpf delete. Running an H&S Mini Maxx tow tune.

When the truck is pulling heavy (#10K+ trailers) and under hard load (like a climbing a grade), the fuel filter will go from 100% to 0% and if I don't back out of the throttle immediately, it will de-rate. When you clear the code 0087 (fuel rail pressure), filter goes back to 100% and full power stays. If you stay in the throttle when the filter message comes on, it de-rates. Coming back from a job in the mountains I just kept my scanner plugged in and reset it every time the filter would drop to 0%.

There doesn't seem to be any issue with driveability, the truck doesn't stumble, hesitate, misfire, nothing. It just de-rates with little warning. Fuel filter changes don't help- I cut open the engine mounted WIX filter and it was very clean. I've inspected all the fuel lines from the tank to the filter, all good.

I haven't checked fuel pressure at the air dog yet but its brand new so not a suspect. I have a feeling I'm dealing with the fuel pressure sensor acting up. Need to get a scanner on it but its hard to duplicate the condition on demand. Idle is good so I think the FPR is OK.

Ideas? I am tired of throwing money at this thing.

 

That sounds to me like the fuel rail pressure relief valve. Once you pop that thing it will keep popping and at lower pressures which would obviously drop your fuel pressure out but it comes up as low fuel rail pressure. For me it did anyways. I bought a fuel rail plug from PPE it was like 40 bucks. You pull the relief out and put the plug in.

 

Wow, is this Justin? Seriously... my diesel shop guy called me yesterday (after this has been on both of our backburners for a few weeks) and said he got me a factory fuel filter delete bowl (since we have the airdog) AND that we should delete that relief valve you just suggested.

We're going to try that next week. Hope it fixes it.

Thanks for the help!

 

No I'm not Justin I know a few people that had these issues with their lmms and most of them were told to buy a lift pump or replace filters or rebuild filter head. That fuel rail pressure release is a known pos on the lmms maybe other duramax too. Once you build enough pressure on the rail it opens and then will only get weaker. My truck like I said popped up a low rail pressure code. Good luck bud.

 

We've got some miles on this duramax (over 5K now) since i did this fix and it has not thrown any fuel related codes or derated. Fuel rail plug seems to have fixed it (and hopefully this post not jinxed it).