Duramax Losing Power

December 11th, 2009

I’m looking for someone to help me. I have a 2001 Duramax with 118,000 miles on it. It had one injector changed at 87,000 miles and ran fine until 102,000 miles.

I’m looking for someone to help me. I have a 2001 Duramax with 118,000 miles on it. It had one injector changed at 87,000 miles and ran fine until 102,000 miles. All of the injectors were replaced at 102,000 miles due to an engine power issue when towing. Along with the new injectors, I installed an auxiliary fuel filter to help prevent another injector failure due to poor quality fuel. Now at 118,000 miles, and with the warmer temperatures, the engine is again losing power after idling for a few minutes. If I shut off the engine for a couple of minutes it sometimes returns to normal, but the service engine soon light stays on.

The dealer reports that diagnostic trouble codes P0089 and U1041 are being set. I would certainly appreciate any insight you might have.

Eli
via the Internet

Diagnostic trouble code P0089 – The ECM commands the Bosch high-pressure fuel pump to deliver a specific fuel rail pressure – that can vary up to 23,000 psi depending on load and speed. The actual pressure is monitored via the fuel rail pressure sensor. If the fuel rail pressure varies more than desired or if commanded fuel pump flow is 100mm3/second or less, DTC P0089 will set.

Corrective action includes measuring the fuel rail pressure using a Tech II scan tool, then compare that to commanded fuel rail pressure with the engine running at 2000 rpm. The difference must be less than 20 Mpa.

A blockage in the fuel tank or plugged fuel filter could cause this fault (excessive vacuum in fuel line). If there is less than 5 in Hg of vacuum when measured at the fuel pressure test port at 3000 rpm, the fuel pressure regulator could be defective, and may need to be replaced. The fuel pressure regulator (FPR) is a sub assembly located on the Bosch high-pressure fuel pump.

Diagnostic trouble code U1041 – Refers to a problem with the Electronic Brake Control Module (ECBM) or anti-lock braking system, and does not affect the engine running characteristics.

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