P0087 SAGA

I just returned to Illinois from Quartzsite towing my 12,000-pound fiver. I have 123K miles on my ’09 LMM Duramax at this point. I had no problems going south in January, but the truck experienced several P0087 episodes on my return to Illinois last week—usually on the bigger hills, a couple hours into the day, and with a lower fuel level in the tank (the usual cast of characters, evidently).

This is an absolutely stock truck that is regularly serviced by our local Chevy dealer. I have faithfully used Power Service fuel treatment since day one in every tank. I’ve also equipped the truck with auxiliary fuel filtration almost from day one. Both the auxiliary and stock fuel filters have been regularly serviced at their recommended intervals.

I’ve spent a lot of time online doing research on the trouble code P0087 looking for any possible short-term or long-term solutions. In getting home, the last 1,000 miles was a big problem. I tried to keep post-turbo EGTS in the 1,000-degree range, and never let it exceed 1,100. I used that as a proxy for the temperatures the injectors and incoming fuel might be experiencing. I operated the transmission in manual mode, which allowed me to select transmission gearing on hills, which allowed for better management of exhaust temperature.

Since returning home, I returned the truck to my dealer and they found nothing wrong. The injectors tested solid (as they did just before I left). No codes were remaining, of course. Absent the load from towing a heavy trailer on hills for hours on end while hot, there was no way to get their equipment to confirm my truck’s problem. In addition, at my request they inspected all fuel lines (appeared solid or had already been replaced), the fuel cooler was clean, and they found no fuel leaks anywhere.

These are two guys who have known the truck since new, have serviced it thoroughly and regularly, and otherwise have my full confidence. They did mention that freeing up the exhaust might help keep overall exhaust temperature down and thus keep the returned fuel cooler. Coming from a dealership, I found that interesting. For now I guess I’ll keep driving carefully and see what the future holds.

Any thoughts on the exhaust change? How about my strategy of using EGT as a proxy for fueling performance? Or for that matter, on any other recent developments on this P0087 code problem for medium-age trucks that work hard?

Rich Phillips

Via Email We’ve received quite a few queries throughout the years expressing dismay or sometimes even anger over the possibility that the injectors needed to be replaced in the 100-150K mile range.

It’s never convenient or pleasant to think about replacing the injectors. Right or wrong, most owners believe the injectors should last for as long as they own the truck. This bristling resistance to injector replacement happened a lot less often with 6.5L diesel owners, largely because the

injectors were/are a tenth the cost. 6.5L injectors needed to be replaced when engine roughness, start-ability, fuel economy, or performance said it was time, which usually wound up being in the 100-150K mile range. Whether they employ current technology or are old-school, all diesel fuel injectors wear out with time and miles.

The OBD-II explanation for this trouble code indicates that the “Fuel-rail System Pressure is Too Low”, meaning the fuel rail pressure is below what the programming expects. P0087 will set if the actual fuel rail pressure is 20MPA below that commanded by the ECM. Due to a variety of possible reasons, the high-pressure CP3 fuel pump simply can’t produce the pressures.

Here’s a list of the possible causes of a P0087 code:

1. Plugged fuel filter through contamination or gelled fuel in cold weather.

2. Plugged vent in the fuel tank cap causing excessive vacuum.

3. Kinked hose in the fuel supply (near the tank or near the engine).

4. Worn injectors, which bypass more fuel back to the fuel tank through the fuel return lines than the high-pressure pump can keep up with. 5. Worn high-pressure pump, which can’t generate the necessary pressures.

6. Defective fuel pressure regulator (FPR).

7. Dirty or otherwise obstructed fuel cooler, which is located just ahead of the fuel tank. This cooler is there to reduce the temperature of the hot return fuel before it enters the fuel tank. 8. Defective or incorrectly operating pressure relief valve in the fuel rail.

We spoke to a guy a few years ago who had a 2009 model that he used to pull a 5ver that was experiencing the P0087 code problem... until he installed a large auxiliary fuel tank in the bed of the truck. He ran a fuel transfer system that cycled fuel through the aux tank and his frame-mounted tank. This ended his P0087 problem. Hot, thin fuel, as he discovered, was a key factor in his P0087s, or at least cooler fuel masked the root cause.

Additional coolers, auxiliary fuel tanks, and other less costly attempts to solve the problem might help in the near term, but they may not be a long-term solution. Anytime you encounter a hot summer day while towing a heavy load, and the fuel heats up as the day progresses, you may see the dreaded code re-appear.

There’s a percentage of owners who simply trade their trucks in for a newer model when faced with the same situation. That’s one way to deal with it. Another way to deal with the shock of repair costs is to acquire an aftermarket engine warranty, before you need it, that covers the

fuel injection system once the factory warranty expires. This could be the best way to deal with the specter of a breathtaking repair bill. Insurance coverage that covers the fuel injection system won’t be cheap, but it’ll be easier for most owners to deal with than dropping a thick stack of $100 bills on injector replacement.

A small number of vendors have been experimenting with ECM programming in an effort to deal with P0087, trying to widen the window of acceptable fuel rail pressures to beyond the 20MPA GM chose as acceptable, to compensate for lower-than-expected rail pressures due to the heat and/or worn injectors/pumps. This isn’t an easy task, and the programming changes have produced varying degrees of improvement. Contact Kennedydiesel.com for programming options that are designed to deal with P0087.

As equipped from the factory, none of these Duramax-powered trucks run with an electric fuel lift pump. Instead, the Bosch high-pressure pump located in the engine valley pulls fuel all the way from the fuel tank, through the lines, and through the fuel filter before reaching the high-pressure pump. This generates 3-5” of vacuum or even more if the fuel filter is partially clogged. Some Duramax owners and aftermarket vendors feel an electric fuel lift pump can help reduce the occurrences of rail pressure trouble codes. A number of vendors advertising right here in Diesel World carry lift pump kits.

As to whether a performance-oriented exhaust system could help lower exhaust temperatures, we actually performed an extensive test some years ago using a Duramax-powered truck to help answer that question. Here are the results from that towing test (towing a 7,000-pound trailer on a 6% grade). The exhaust temperature remained the same for each run, though there was a measurable improvement in performance.

Stock power w/stock exhaust: Boost 21 psi, EGT 1,275 degrees, speed 62 mph in 4th gear.

Stock power w/magnaflow exhaust: Boost 21.5 psi, EGT 1,275 degrees, speed 64 mph in 4th gear.