Power loss--2000 Dynasty 350 ISC

[Terry L T]

When I lost power I also lost some of the Pac braking, it turned out to be a broken exhaust manifold. I do not know what the boost was at full throttle.

[Vanwill]

Thanks for the replies. I'm in a remote section of Colorado and the coach is performing well enough to make the rest of my trip through the southwest and home to southeastern NC.

I'll check out a few things when I get home early November. The relief valve for the "crankcase" of the injector pump is a known failure item. I'm leaning toward adding a FASS (or similar) pump system. Do I have a diagnosis I'm confident of? NO. But raising the internal "crankcase" pressure of the injection pump was a common performance upgrade to the old 8.3 mechanical engines. I installed that performance upgrade on my 1993 Dynasty and it made a noticeable difference. To do something similar on the ISC-350 requires bypassing the lift pump.

Thanks for your replies!

[bjbear]

From the symptoms described, it would appear to be a lack of fuel. I would suspect the lift pump first, then the HP injection pump. If it is the lift pump, you want to correct that ASAP as under pressure at the injection pump can result in damage to it as well. I hope I am guessing wrong as the injection pump can be a bit pricey.

[Ivylog]

The electric lift pump is only a starting aid as after 30 seconds it shuts off automatically. The injection pump has a mechanical gear pump that supplies the fuel once the engine is running fast enough. The FASS pump is more advertising than actual need.

The only reason you replace the lift pump that runs is if it continues to leak after tightening the three small bolts that holds the electric motor on it.

[bjbear]

Originally Posted by Ivylog

The electric lift pump is only a starting aid as after 30 seconds it shuts off automatically. The injection pump has a mechanical gear pump that supplies the fuel once the engine is running fast enough. The FASS pump is more advertising than actual need.

The only reason you replace the lift pump that runs is if it continues to leak after tightening the three small bolts that holds the electric motor on it.

Did not know that. On my Dodge 3500 Dually, my lift pump quit and I got to sit on the side of the road waiting for a tow truck.

[Ivylog]

Yes, on a ISB Cummins the lift pump runs all the time but on the ISC, ISL it runs for aprox 30 seconds. I put fuel filters on dry and cycle the key 4 times (2 minutes) to fill the filter with fuel and get air out of the system on my ISL.