P0087 fuel rail pressure low limp under high loads

[CoyleJR]

I just returned home from four months on the road pulling our 38' 5th wheel. The truck and 5th wheel have a combined weight of 23,800 lbs and the temperature was often well over 100 degrees. My truck is a 2006 LBZ with 240,000 miles and this is the first time it has shown P0087 code. I found that if my fuel tank level was below half a tank, the temperature was over 100 and the truck was working hard pulling a steep grade it will throw P0087 code. I was able to repeat this problem code several times and fix it by opening the valve on my second fuel tank and adding fuel to the primary truck fuel tank. For 240k miles I have always kept the truck tank full by gravity feed from the secondary tank. This trip was the first time I let it get below half a tank of fuel. A full fuel tank must cool the hot fuel returning from the motor and that cool fuel keeps the truck from showing the P0087 code. I realize that there can be several causes for a P0087 code to show up but on my truck high fuel temperature seems to be the cause.

Additionally, I keep the small fuel cooler radiator in front of the fuel tank very clean and I am now considering installing a second fuel cooler on the right side of the truck.

[richp]

Hi,

Just returned to Illinois from Quartzsite towing the fiver. I have122k miles on an '09 LMM. No problems going down in January, but several 0087 episodes on return last week. Absolutely stock truck with auxiliary filtration and regular Power Service throughout its life. Regular filter changes. Regular Chevy dealer service at the same competent location. No lift pump (duly noted, John).

Obviously, working through this thread gives possible short and long term answers. But my solution for getting home the last 1,000 miles -- starting in western Oklahoma -- was to keep post turbo EGT's in the 1,000 degree range, and never more than 1,100. I used that as a proxy for the temps the injectors and incoming fuel were experiencing. I did this by doing a lot of manual gear selection on hills. I recall only one post in this entire thread that mentions that approach. Hmmm.

I will figure out my future with this truck somehow. But when other brands of diesels are notable for much longer injector life, it makes me wonder what GM has stuck us lifelong, committed customers with.

FWIW.

[richp]

Hi,

My dealer had it for two days, and as I expected, found nothing wrong -- injectors test solid, no codes left, and absent the load from towing heavy, on hills, while hot, no way to get their equipment to register my issue. They report all fuel lines solid, the fuel cooler clean, and no leaks anywhere.

These are two guys who know the truck since new, have serviced it thoroughly and regularly, and otherwise have my confidence. So for now I'm going to drive on and see what the future holds.

They did offer a thought that freeing up the exhaust might help keep overall temps down and thus keep the returned fuel cooler. Coming from a dealership, I found that interesting. Any thoughts on that from anyone?

[CoyleJR]

Hi Rich,

I agree with the dealer that opening up the exhaust would help cool the motor by lowering the EGT a little. I do not think it will get you a substantial drop in fuel temperature. Additionally, the noise caused by most large exhaust systems will make for a very long trip from Illinois to Arizona next year.

My post about the P0087 code was the one posted just before your post (take a look). If I keep plenty of fuel in my fuel tank it seems to cool the returning hot fuel and stop the P0087 problem. When your truck threw the p0087 code did you have over half a tank of fuel? I think a second fuel cooler would cool the returning hot fuel a lot better than a larger exhaust system. Just my thoughts on the P0087 code.

Good luck
John

[richp]

Hi John,

Thanks for the response.

I usually fill up at the end of the day's run with the fiver, so I can get a fast start in the morning. And I have been getting a few hours of clean performance -- until the tank is lower and the day is warmer. So refueling more often might help, although it would slow the day's progress.

I have pondered adding another cooler. Insofar as I recall, nobody in this thread has mentioned actually doing it, or a supplier with suitable hardware. So that is an option with dangling questions...

And yeah, the exhaust noise issue has occurred to me, and would be a turnoff. In addition to my own objection, I might never get Maureen to ride with me again. A very last resort, I think.

I appreciate being able to add your thoughts to the mix.