UPDATE 3/13/10: Shepherd Engine Saga - Epilogue

[buswarrior]

What a journey, and we all learned something along the way!

The hobby, and I, thank you, Jim!

happy coaching!
buswarrior

[rv_safetyman]

Epilogue:

When I last posted, it looked like the low boost pressure problem was solved by switching the replacement engine ECM back on the engine.  The issue was incompatibility of the boost pressure sensor with my original engine ECM.  Subsequent testing has proven that the switch in ECMs has solved the problem.

I had mentioned that I was reluctant to use the replacement engine ECM because of compatibility problems with the bus and transmission parameters.  That concern proved to be founded.  I was not able to pick up speed, because the AutoShift supplies the speed signal via the J1939 connection and the ECM options were only tail shaft and wheel sensors.   I used the ProLink to list all of the settings for the two ECMs, and found the two settings that needed to be changed.  Problem was that the ProLink could not change the options, as they were not a part of the ECM software options.  I ended up removing the ECM and taking it to Stewart Stevenson.  They were nice enough to reprogram the ECM free of charge (5 minutes connecting and two minutes of programming since I knew what needed to be changed).

Today I took it on my big test run.  I drove it down to Denver to fuel up.  That is a 70 mile round trip.  On the way home, the elevation changes almost 3000 feet (~~8200 feet max) in about 10 miles with some very steep climbs.  That really maxes out the engine in several places.

The bus ran fine and the highest boost I saw was 27.4.  Lots of power.  Had to back off in a couple of places because of the charge air cooler/inlet air temperature got higher that I wanted (fan issues that I have the parts to resolve and mister not hooked up).

Thanks to all of you for giving me both information and support!!!!

Jim

[johns4104s]

Jim.

i am thrilled you got the boosere problem solved look to see you at a future rally or two.

I know the radiator mister is used by many, but if the Radiator/fan and piping is in good shape should there be a need for additional water?

John

[rv_safetyman]

John, my radiator does a great job.  The issue the the charge air cooler which I had to install on the other side.  I now use four pretty good electric fans, but I will be switching to a two speed hydraulic fan with one large blade. I have the air ducted down so that the fans are not fighting the big radiator fan.

I forgot to say that we will be heading to Albuquerque next week for the FMCA Rally IN THE BUS!!!!

We hope to make a few bus rallies this year as well.

Jim