6CTA8.3 won't start after fuel filter change

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100,000 Miles

Union Pacific

My 8. 3L Cummins in 1991 Diesel Pusher won't start after I changed the fuel and fuel/water sep filter. I manually pumped the lift pump. The only thing I did not do was open the low and high pressure lines to bleed out air. Would this cause it not to start? Thanks
 
Always

I always fill filter with fuel before reinstalling, it is a little messy but worth the hassle. It takes a long time to prime with button and still retains some air. Also check and see if old filter gasket is maybe stuck in housing? I fought a filter on a Cat one time, finally pulled the new filter off only to find a piece of cellophane wrap on seating surface causing air leak.
 
You changed two filters right? One on the engine, and one in a side compartment towards the back of the rig?



These things are always a pain to start if the do have have an aftermarket priming system. Pushing the prime button the fuel pump won't work. The problem is not the filter on the engine, its the separator in the side compartment. The water separator is installed in the fuel line BEFORE the lift pump, which means it is on the suction side. So if it doesn't get prefilled with fuel when you install a new one, you get a giant air bubble in the fuel. Usually, you have to pressurize the fuel tank while cranking the engine. This will put positive pressure on the supply to the lift pump, and will fill the water separator with fuel. Its kind of a PITA if you do not have access to compressed air... If you do not have compressed air available, take the filter back off and fill it with fuel. :D
 
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