P0087 fuel rail pressure low limp under high loads

[Mark Rinker]

Update: Interesting observation today while running same route from Grasonville, MD through mountains of MD, WV, PA...the route that tripped the P00087 countless times in July with a SeaRay 310 (12000#) in tow at 85F outside temps.

Today was a Chaparral 350l, tipping the scales closer to 15K#, but the outside temps ranged from 14f to an icy 9f.

You guessed it...no matter how hard I drove the truck (extended 4th gear, 3000rpm charges up 8% grades to maintain 55mph, passing semis with their flashers on one after another) I never set the code all day.

So...it may be a worn injector situation that causes the high return rates, that heats up fuel, that contributes to low rail pressures...BUT...the biggest cause is

HOT FUEL. (period)

Somebody make a bigger undercarriage mounted fuel cooler with fan assist and I think you'd narrow the window considerably, if not eliminate it entirely, throughout the lifespan of the injectors. I have 155K on my originals and they are running as strong as day one. Not touching a thing, certainly not for a pesky code where I can push a button and 'fix' the programming error. Its certainly not worth installing new injectors to fix, at least not in my case which is towing heavy on hot days in the hills.

I know...how about we programmatically correct this bug in the ECM?

[Kennedy]

I still have guys calling me with this issue in the winter months here. Odd, but some are still having issues. I've sent out some revised tuning and made sure that they understood that things may change when it warms up so we'd readjust then. Only time (and hot weather) will tell.

The big fan fuel cooler idea may help, but you can't get below ambient in the tank and I think on a hot summer day she'll just heat right back up again as the temps are coming from the journey across teh valley to the CP3, the pressurization within the CP3 and probably to an even greater extent from the release/backflow at the injector.

[Maxdout1]

Im having the same problem on a 06. I put 8 new gm injectors in and still having the same problem. It only does it at wot and when its warm. Pump at idle you can ramp it up to 24000 psi and hold it all day. when it warms up it will command 26000 and drop to 12000

[Demilee]

Today we brought our truck to a guy that specializes in fuel line issues here in Austin, TX. We finally bought a device to reset the code back in Sept so we haven't been wasting time waiting for limp mode to clear on its own. That seemed like major progress at the time.

However, the whole issue seems to be getting worse and becoming more of a pain to reset while driving, especially in traffic. We feel that towing 12a + ton toy hauler and dealing with these limp mode issues is going to become unsafe at some point. The code is now setting at lower temps than before (low 60s) and while going up minor but long inclines. In a nutshell the issue seems to be getting worse.

Once we get our official diagnosis I will post back here.

[GM Customer Service]

Today we brought our truck to a guy that specializes in fuel line issues here in Austin, TX. We finally bought a device to reset the code back in Sept so we haven't been wasting time waiting for limp mode to clear on its own. That seemed like major progress at the time.

However, the whole issue seems to be getting worse and becoming more of a pain to reset while driving, especially in traffic. We feel that towing 12a + ton toy hauler and dealing with these limp mode issues is going to become unsafe at some point. The code is now setting at lower temps than before (low 60s) and while going up minor but long inclines. In a nutshell the issue seems to be getting worse.

Once we get our official diagnosis I will post back here.

Please let us know any updates you may have! We are here at your convenience.

Brandon
GM Customer Service

[Demilee]

First of all, I'd like to thank Mr. Rinker for suggesting we purchase a scanner to clear our codes while driving. We were so sick of waiting on the side of the road for the limp mode to clear on it's own. We finally got one last summer. BTW the code only did clear on it's own as trans. temps got lower. Maybe that can info can help someone out? Maybe that has to do with the FUEL temps?!?!?!

Anyway, I'm reporting back regarding the service we had done in Austin for the P0087 codes we are getting... We were hopeful that the guy at the shop was correct when he thought that it was a valve and seal (used to diagnose fuel pressures?). It ran about $90 to replace that, he noticed it was broken just after opening the hood of the truck. He said if that didn't work he recommended "Kill'Em". (We have not tried that since we were going to be towing in a few days and wanted to see if the valve replacement worked.) He tested the fuel injectors and said they all looked fine. (Even though we were told at a Chevy dealership in Pensacola, FL in 2011 that we needed 4 replaced!)

So, our trip from Austin, TX to Tucson, AZ started out great! We thought that we had found our FRP Savior. Nope... We left early in the AM, when the temps were low. My story is quite consistant with Mr. Rinker's you see, high outdoor temps and under load with hills pops P0087. We ended up stopping to take a nap and let the temps cool outside. The cool desert night is our friend with this FRP issue.

Interestingly, we got a code of p2002 a two times within our 1.5 days of travel to Tucson. Also, got a p2563 code as well. I understand these are both emissions codes, likely unrelated? If no, maybe that is another clue?

With the 85k miles we have put on this truck driving around the U.S. for the past one and a half years, UNDER LOAD half of the time, I've also come to believe this is a FUEL TEMP issue. This supports Rinker's theory and has been mine for awhile as well. I do 95% of the driving when we're towing. It's like I know the truck personally now, and I know when it's going to pull the dreaded p0087 code.

Since I am a "dumb" girl at least I had enough sense to ask the last mechanic about where the dang fuel cooler was so I can try to clean that next. I'd rather not pull out the bottle of "Kill'Em" we bought. That stuff is lethal, I can't believe you can even buy it over the counter. (I'm a bit of a klutz and I'm afraid it will get on me.)

I'll be checking back again soon after some more troubleshooting. I welcome any feedback. Cheers!
-Demi

2008 Silverado - 3500 HD DRW (189k miles - symptoms since ~115k - purchased at 105k)
*We've had the GM bulletin PIP4526 collapsing fuel line issue addressed already.
*Our fifth-wheel is 11-12.5 tons. (arrived 21k from the manuf.)

[cabletech]

Demi

Is your sig correct that you 5th wheel is 21k lbs dry? If so that is way over the towing capacity of your truck and contributing to (or causing) your hot fuel problem.

Jay

[CoyleJR]

Demi,

I agree with Cabletech, if your trailer is 21k # you do NOT have enough truck to pull it or stop it. The total weight of your truck and trailer would be 29k to 31k #. Your truck appears to be similar to my 2006, CC, Dually and it is rated to haul (truck & trailer) 24k #. I think you just added the truck weight to the trailer weight in your signature (I hope). If your truck and trailer weigh around 24k # you should be OK. If you are actually running a total combined weight around 30k # you have far exceeded the design limits of the truck and that is likely the cause of your problem.

Last week I posted a suggestion to pressure wash the fuel cooler and to run as much fuel in your tank as possible and see if you were still setting the P0087 code. To wash the fuel cooler go to a self operated car wash. Then lay on the ground and spray the one foot square radiator looking thing mounted under the bed behind the drivers side of the cab. When you think it is clean spray it some more. I always am impressed by the amount of dirt that is left on my driveway when I clean the cooler. Additionally, experiment by topping off your fuel tank when it gets down to 3/4 full capacity for a travel day or two and see if it helps with the P0087 code problem. On a diesel motor part of the fuel that is pumped to the motor returns hot to the fuel tank and the full fuel tank will help to absorb the heat from the returning fuel.

I hope things start working a little better for you with the truck. You indicated you were in the Tucson area and I would suggest that you camp at the Kartchner caverns state park (I10 & SR 90) and take day trips to Tombstone and Bisbee. The caverns are great, Tombstone is fun and my family really loved the mining car ride into a 100 year old mine in Bisbee.

If you do weigh around 30k # be very careful in the Az mountains. I am very cautious and I have still had my brakes smoking on these hills.

Good luck & safe travels
John

[CoyleJR]

Jeff,
If you don't have a scanner that will clear the codes while driving you may want to consider purchasing one. You could have a loooong drive back to Co if you can't easily clear the codes. It may help if you try keeping the fuel tank as near full as possible, traveling in the evening or night and keeping your speed around 60mph. I personally think the biggest factor with the P0087 code problem is hot fuel. You seldom hear of anyone showing a P0087 code in the winter months.
Good luck
John

[Kennedy]

Im having the same problem on a 06. I put 8 new gm injectors in and still having the same problem. It only does it at wot and when its warm. Pump at idle you can ramp it up to 24000 psi and hold it all day. when it warms up it will command 26000 and drop to 12000

I can only speculate that you may benefit from some tweaking in the tuning. This is ASSUMING thatyou are not running a plastic bodied fuel filter and have no excessive restriction.

I'd probably start by lift pump supply pressure first.

[CoyleJR]

I often tow 24k lbs in the Arizona mountains at 115f and my 185k mile LBZ truck has never set P0087 code or gone into limp mode. I have a 100 gallon aux fuel tank and a gravity/check ball feed into the 34 gallon primary fuel tank. This system keeps the 34 gallon truck tank full at all times. I think the full tank of fuel absorbs a lot of the heat from the hot return line fuel which helps keep the entire fuel system cool. Additionally, I pressure wash the fuel cooler under the truck bed about every 30-60 days.

I would suggest to anyone setting the P0087 code to pressure wash your fuel cooler and keep as much fuel as possible in your fuel tank when towing. It won't cost anything and it seems to be working for on my truck. I could just be lucky and my truck could start acting up tomorrow.

Good Luck
John

[Mark Rinker]

I often tow 24k lbs in the Arizona mountains at 115f and my 185k mile LBZ truck has never set P0087 code or gone into limp mode. I have a 100 gallon aux fuel tank and a gravity/check ball feed into the 34 gallon primary fuel tank. This system keeps the 34 gallon truck tank full at all times. I think the full tank of fuel absorbs a lot of the heat from the hot return line fuel which helps keep the entire fuel system cool. Additionally, I pressure wash the fuel cooler under the truck bed about every 30-60 days.

I would suggest to anyone setting the P0087 code to pressure wash your fuel cooler and keep as much fuel as possible in your fuel tank when towing. It won't cost anything and it seems to be working for on my truck. I could just be lucky and my truck could start acting up tomorrow.

Good Luck
John

x2 on the HOT fuel theory. I assume these are your original factory sprays, John?

[CoyleJR]

Mark,

Yes my truck is running the original (from the factory) injectors. The only things that are not original on the truck are the drive shaft carrier bearing, one glow plug #8, and tires and brakes. It is the best truck I have ever owned. Good luck when you relocate.

John

[Mark Rinker]

Im having the same problem on a 06. I put 8 new gm injectors in and still having the same problem. It only does it at wot and when its warm. Pump at idle you can ramp it up to 24000 psi and hold it all day. when it warms up it will command 26000 and drop to 12000

This supports my theory that its about HOT fuel, as much or more than return rates. That should have been solved with new sprays. How many miles on the truck when it first occurred?