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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29457
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have 02 duramax new filter,primer pump kit installed

Customer Question

i have 02 duramax new filter,primer pump kit installed ,different diesel injector driver fuel lines from tank and cooler last summer, all new hoses on top of motor.last fall.starts when cold won't start when warm or hot
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.

HI there, I am Cam. Can You tell me if your injectors have ever been changed?

These are NOTORIOUS for bad injectors and the test below will confirm they are bad.

These use hydraulic pressure from the fuel system to operate the injector. SO a small amount of fuel is supposed to bypass to open the main part of the injector to make it operate. When these start to fail, this causes to much fuel to bypass and return to the tank. This resulting fuel loss will lower the fuel rail pressure and at a time when the pressure is needed most, during cranking, it takes longer to build the required 1450 psi to operate the injector. SO the test we do is this. Find the 2 fuel lines on the rear drivers side valve cover. Take the smaller one off and attach your hose to the metal pipe coming from the engine. Put the other end into the container and run the engine to fill that line. Then shut it off and remove the IGN 1 relay from beside the starter relay. If the engine will not start at that time, crank it to fill the line, then empty out the container and keep the line full. Crank the engine for 15 seconds fully and measure the amount of fuel that comes out of that line. More than 24cc means the injectors have failed and they need to be replaced. The code 2 LLY engines can test each injector individually, and the spec is 3ml or 3cc each for the same cranking period.