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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1492
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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Chevrolet: have a 2006 chev duramax code p0087 if I command

Customer Question

have a 2006 chev duramax code p0087 if I command fuel pressure up with computer it goes up but if I just rev it up with code cleared it goes up to desired but then drops down and light comes on
Submitted: 5 months ago.
Category: Chevy
Expert:  Juan Crespo replied 5 months ago.
Hi there.First thing to do is make sure the fuel filter is new and has no restrictions. Once that's OK, check the flexible fuel lines at the engine and under the vehicle near the transmission for kinks; replace them as necessary.If the fuel lines are OK, then check fuel return rate:Disconnect the fuel return hose from the pump and the return line from the back of the engine. Cap off the part of the return line where the pump return hose would have been hooked to and then hook a hose to the pump return and put it into a measuring container. Factory spec is less than 2 ounces of fuel returned for the whole system (minus the pump) for 15 seconds of crank time. So, hook a hose up the normal return portion and crank it over until you get fuel going into your container. Then crank it for 15 seconds and see how much you have. If it is more than 2 ounces, you'll need to dig deeper and isolate whether it is an injector or the fuel pressure relief valve. The pump can return quite a bit of fuel and mess up your results if left in the system during testing. If you have less than 2 ounces and still have low rail pressure, then most likely you have a failed pump.Please let me know what you find.