Engine/Transmission (1998.5 - 2002) ISB Down

[Greenleaf]

It's nothing new to have one of many ISB powered buses drop out of service due to fuel/electrical problems. I now have one that has four failed injectors :{



I found that when there are no engine codes and the engine will not operate well, it's mechanical in nature. In the past it's always been one injector. Now four at once The point being if there are zero codes, the fuel filters are new and the pump has ample fuel supply it could be mechanical in nature. The engine operated pretty well at 55 MPH so I knew it wasn't sucking in air. It simply had low powewr and missed. The slow idle was like it had only four cylinders.



The heat gun test did not work as all cylinders developed heat. Four injectors were reported as "failed" by Northwest Fuel Injection. One was fairly new so it was working. Another was reported as operating normally.

 

[Bob4x4]

How many miles?



Bob

 

[Greenleaf]

132,841 miles 1999 model year. Three injection pumps, three lift pumps. This is just one of many ISB engines in a fleet of 25 buses.

 

[WestTN]

With 3 IP changes there have been 3 oportunities to get dirt in the injector lines. It doesn't take much to clog those tiny injector holes.

 

[Turbo Tim 1]

I'm thinking the ULSD is going to be a pain in the butt, you've probably been running it for a while and I think things are loosening up in the tanks

 

[Greenleaf]

WE use a small mix of Bio fuel time to time. When we do, some of the buses will exhibit plugged filters with little or no warning. The school will not pay to have the 12+ year old storage tank cleaned :-{}



Lucky for us many of the injection pumps are being replaced under the Cummins recall of the VP-44 unit. They claim the injection pump will go bad resulting in a sudden loss of power or engine shut-down.



really?

 

[59Turbo]

Lucky for us many of the injection pumps are being replaced under the Cummins recall of the VP-44 unit. They claim the injection pump will go bad resulting in a sudden loss of power or engine shut-down.



really? [/QUOTE]



Recall?? Is this just for the buses or does it apply to all vp44 equipped engines?

 

[Joe Mc]

59Turbo - I was thinking the exact same thing. Any answers there Greenleaf? I'm keeping my fingers crossed . . .

 

[Greenleaf]

Just in the school bus application... ... for now.



Baybe cuz they haul kids and a pickup in only one or two persons?????? I don't know.