Question for Dave on C9 Turbo

[Mike Shumack]

Hi Dave,
I was reading the irv2 form (Cat engine section) and came across this post. It's not my coach, but I am interested in learning. Can you shed some light on this code?

I have the dreaded SPN 641 FMI 7 code and I'm having a very difficult time finding a location to replace the turbo. I'm aware of the issue associated with the 2007 ACERT c-9 and I guess it time for me to pay the piper.
...
2007 Beaver Contessa

I'm just curious about this code and learning more about the CAT engines and its problems.
I googled the code and I only come up with links to Cummins and Volvo engines with VGT (Variable Geometry Turbo actuator issues). My CAT diagnostic code list does not have this code.

Is this a legit CAT code? If so, does it mean the turbo is bad? Does the C9 have some "known" problems with its turbo?

[David T. Richelderfer]

Mike - I used Google with this search argument "SPN 641 FMI 7 code in cat c-9 engine" and found some interesting reading.

[Mike Shumack]

I guess the C9 has the VGT then.

[David T. Richelderfer]

VGT?  Had to look it up.  How quickly you passed up my knowledge base!

[Mike Shumack]

I didn't know (don't know if) the C9 has a VGT turbo. Dave Atherton would know.

[Joel Ashley]

Problems referred to may be related to engines from 2007 on that have exhaust particulate removal systems, ACERT C9’s?  Your era engine, Mike, should not be relevant.  Check this thread:  http://beaveramb.org/forum/index.php?topic=1483.0

But we’re stepping on Dave’s toes here... you asked him.

Joel

[Mike Shumack]

Yes Joel, I have a C13. I'm asking about the C9 here because I want to know more about it.
That link had some good info. thanks

[Steve Huber Co-Admin]

I think you are referring to the turbo issue on the 425HP C9. It does not affect the 400 HP C9s. While the 425 was built by Cat in 07, many 07 coaches and some early 08s still have the 400 HP unit due to chassis "build aheads" by the chassis builders.  See http://beaveramb.org/acadp_listings/cat-c9-turbo-problem/ for more info.
Steve

[Gerald Farris]

Mike,
The C7 and C9 engines that were built after January 1st 2007 used in Beaver coaches are equipped with a DPF (diesel particulate filter), and therefore they are also equipped with a VGT turbocharger that acts as the exhaust brake. The DPF system has a regenerator to burn the soot out of the DPF when it becomes restricted, and the regenerator is mounted in the exhaust pipe right after the turbocharger. Therefore, the variable geometry turbo blades are reversed to create back pressure in the engine exhaust, and effectively become the exhaust brake because with the regenerator a butterfly valve style can not be used. Like Steve said above, the engine build date does not corelate to coach build date because large numbers of pre 07 engines were bought by Monaco to avoid the more expensive and more complicated 07 DPF equipped engines.

Gerald       

[Dave Atherton]

Gentleman, the Caterpillar C-9 is 400 hp, the engine in question is Caterpillar C-9 S 425 hp
Will leave the Caterpillar C-7 out of this picture. The Caterpillar C-9 S has a vairble pitch vane
turbo and not a external wastegate. On road and will be in Farmington around noon on the
29th. I can answer and printout technical information off caterpillar service information system
( SIS ) on this subject. Dave Atherton Retired Cat Mechanic