P0087 fuel rail pressure low limp under high loads

[Mark Rinker]

The gauges would have to be mounted in the cab - not under the hood, so you could monitor restriction under high loaded fuel demands, while driving uphill, loaded with trailer.

Also, the lines would have to be tapped pre-filter, and then somewhere between the tank and the restriction, which in the case described was somewhere near the transmission.

Honestly, not knowing what we now know of the line collapse under demand and resulting restriction - there would have been no reason to install the gauges in these locations.

[Kennedy]

Actually for the benefit of those who may encounter a similar condition, step 1 is to measure fuel filter restriction. It is not neseccary to measure at any place other than the factory test port at this stage.










Step 2 would be to measure restriction under load provided Step 1 test is passed. Now this gauge has a fixed mount to simplify operation, BUT a hose can be easily added and the gauge placed up under a windshield wiper (standard practice) while the truck is driven.

When troubleshooting something like this the first suggestion I typically make is measure filter restriction. Maybe I need to rephrase this to: Measure fuel system restriction as it seems there is an assumption that a new filter fils this operation. While a new filter CAN, it is never a given. I've seen filters load in as little as a couple hundred miles. Mdrag has not been here in a while, but he and I had this converstion some time back. Out came his restriction gauge, filter verified as loaded and problem solved until it loaded again...

[Mark Rinker]

Got it! That will really help the next time I am troubleshooting fuel related issues while hauling big oversize boats across the US or Canada!!!

Thanks, John!

[WhiteTruck]

While rare, there is one potential area that can cause a restriction and yet not be detected by checking at the factory test port. There is a short section of line/hose that is AFTER the test port going to the injection pump. The rubber part could deteriorate internally, causing a restriction. I wouldn’t look at this until the usual causes of low rail pressure have been checked, but something to keep in mind.

[Clintv331]

For the past few weeks my truck (2006 LBZ) has been taking longer than normal time to start and has gotten worse in the past two days. Well two days ago under normal driving conditions (no load or anything) I get DTC P0087. Once the engine light was on i couldn't rev up more than 2k rpm (in park or while driving). i cleared the code with my tuner and not two seconds later it was back. at first i was thinking it was my fuel filter since it was about time to change it. Well i changed the fuel filter today and then went for a test run. I first cleared the code before taking off. once i got to not even half throttle the dtc was back. it feels like it's not getting enough fuel and is being restricted. when i got back i turned the truck off and when i started it back up it didn't take as long as it did before i changed the filter. also there is a little bit of black smoke coming out the exhaust when at idle. I have it on stock tune.

Could this be due to those hoses collapsing, bad injectors, bad fuel, or what? Can someone please give me some insight on this.

Performance mods: K&N Cold air intake, MBRP 4" turbo back exhaust, & Bullydog PMT

Thanks,
Clint

[Kennedy]

As stated earlier:

There is a simple, sure fire way to test all but the one point of restriction that White Truck mentioned. It also will save you from making premature filter changes and let you know if indeed the filter is loaded:

[Kennedy]

Also watch your WIF sensors. Been seeing some of them start to leak. When an extended crank is noticed I generally recommend pumping up the primer bulb hard and this will often show a leak.

A lift pump would keep the system full of fuel and not air...

[WhiteTruck]

The information in GM PIP4526 is only helpful in the sense that it says that GM approves replacing only the hose portion of the line instead of the complete line(s) they recommended in the past. There is no new diagnostic information in it, as the supply line diagnostic is still done with a restriction gauge as JK recommends for possible causes of P0087, P0093 or P1093.

[Demilee]

Has anyone found a resolution to this problem? We are having the EXACT SAME problem. We've already replaced the hose recommended in GM PIP4526. We had that done in Austin, TX. We thought it worked until we got into some hills in Arizona and California on our drive out there.

We'd rather not spend the $4k+ on fuel injectors if that isn't the problem. Of course we have 117k miles on our 2008 3500 DRW Silverado so a warranty claim is out of the question. We only found out about the issue right after we bought the truck at 105k miles to tow our 2012 Voltage.

Any help would be appreciated!

[Mark Rinker]

I do not know of any solution to this GM programming error, other than (uneccesary) injector replacement.

Have started seeing the same issue with my 2009, starting at 125K miles. In all other ways the truck runs and performs as new.

For the $4500 injectors cost, I'll keep pushing the 'reset' button on my scan tool and clearing codes until someone programatically fixes this bug in the ECM code. When under these conditions, I keep it plugged in and resting on the passenger seat. Silly, huh? I reset the code at least ten times yesterday.

GM should be more interested, as it causes a liability issue when you reduce power to someone towing heavy on a hot day uphill...NOT good.

[greatwhite]

...
For the $4500 injectors cost, I'll keep pushing the 'reset' button on my scan tool and clearing codes until someone programatically fixes this bug in the ECM code. When under these conditions, I keep it plugged in and resting on the passenger seat. Silly, huh? I reset the code at least ten times yesterday...

You just brought back memories of driving down the road with a glitching PMD and the laptop set up on "clear codes" to stay out of limp mode....

Yeesh.