Author Topic: C9 425 Cat on Contessa---low boost  (Read 4508 times)

Dan Murphy

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C9 425 Cat on Contessa---low boost
« on: April 21, 2017, 03:58:43 PM »
We are traveling home from Florida to Indiana but taking our time going up the Eastern Coast. My Contessa has been running fine on these low coastal roads but when I encounter a high bridge I have very little boost [13 psi] and not much power. I been talking to Dave Atherton and he has been thinking about my problem and making suggestions.
I was wondering if anyone else has had this problem and found the fix??

Could it be a sensor? something plugged??

I know we need to cross some mountains to get home and I don't want to get stalled out on some long grade somewhere in West Virginia.

Anyone know of a good reputable mechanic is Coastal South Carolina/North Carolina or Virginia?? I really don't want to go to a caterpillar shop at all!

Thanks for any input.

Dan

Mike Nunn

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Re: C9 425 Cat on Contessa---low boost
« Reply #1 on: April 21, 2017, 04:34:42 PM »
Dan, There is a company call W.W. Williams that is an Detroit Diesel/Allison service center in that part of the country. They helped us out one time a few years ago with a trans issue. They seemed very knowledgeable. We were in Columbia S.C. But they have several shops in North and South Carolina.
I assume they would work on a cat they are pretty big places. Good luck. Mike

LaMonte Monnell

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Re: C9 425 Cat on Contessa---low boost
« Reply #2 on: April 21, 2017, 06:52:27 PM »
We are traveling home from Florida to Indiana but taking our time going up the Eastern Coast. My Contessa has been running fine on these low coastal roads but when I encounter a high bridge I have very little boost [13 psi] and not much power. I been talking to Dave Atherton and he has been thinking about my problem and making suggestions.
I was wondering if anyone else has had this problem and found the fix??

Could it be a sensor? something plugged??

I know we need to cross some mountains to get home and I don't want to get stalled out on some long grade somewhere in West Virginia.

Anyone know of a good reputable mechanic is Coastal South Carolina/North Carolina or Virginia?? I really don't want to go to a caterpillar shop at all!

Thanks for any input.

Dan

Cant say I blame you on the CAT comment.
laMonte
Lamonte & Patti Monnell
2001 Beaver Contessa Naples DP 40' 2 slides
CAT 3126B
2021 Chevrolet Silverado Trail Boss

Weeki Wachee,Fl

Joe Rhea

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Re: C9 425 Cat on Contessa---low boost
« Reply #3 on: April 21, 2017, 11:27:02 PM »
Dan:
I exspearanced a simimular problem with my previous coach. The problem turned out to be a leaking precharge cooler not allowing the boost pressure build up. I would have to get in the upper teens on rpm before I would start seeing boost pressure.

Brad Barnes

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Re: C9 425 Cat on Contessa---low boost
« Reply #4 on: April 22, 2017, 01:52:08 AM »
I have a 2009 Beaver Contessa C9  and just traveled from North Fort Myers FL to my home in Michigan on route I found a similar problem in that I had trouble on the steep mountain grades, I made the decision to try to make it home on the steep grades I got down to 35 miles per hour on two grades on the way home. It ran great other than the steep grades , I have an appointment at the Cat dealer in the next few days, I will keep you posted.

Dale Walker

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Re: C9 425 Cat on Contessa---low boost
« Reply #5 on: April 22, 2017, 02:45:11 AM »
Have you checked your intake hose clamps? My C-9 blew a hose clamp clean off on the hill out of Albuquerque. What blew my mind is on refreshing my self about another subject in the owners manual, the manual suggests to carry a spare spring clamp.

Dave Atherton

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Re: C9 425 Cat on Contessa---low boost
« Reply #6 on: April 22, 2017, 06:39:17 AM »
Gentleman, the Caterpillar C-9 400 hp and the Caterpillar C9S 425 hp are very different  with
turbocharger. and troubleshooting low boost pressure is different as Dave explained on Ask Dave
about a week ago. With the Cat C-9 400 hp. Air pressure into air actuator that controls the opening
and closing the turbo wastegate. The Cat C9S 425 hp has a variable pitch type wastegate that
is actuated via a electric motor. In most cases with the Cat C9S with the regeneration system
the electric motor fails from excess exhaust heat. With the Cat C-9 400 hp lack of or low turbo
boost failure in most cases ( boost pressure sensor part number 161-1704 ) and  turbo boost
regulator ( part number 230-9944 )  that will correct problem. Going back to the Cat C9S 425 hp
With regeneration system required change out of complete turbocharger.
Dave Atherton Retired Cat Mechanic

Harold and Gloria Skipworth

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Re: C9 425 Cat on Contessa---low boost
« Reply #7 on: April 24, 2017, 01:26:57 AM »
Had a similar sounding problem  and my cat service dealer found a hole in my CAC a frozen waste gate and a defective boost pressure sensor.  They looked for a replacement CAC and found that the MONACO  parts had 3 of them. And as the company that made them no longer exists and no one else has one so they wanted $6500 for one.  Cat sent it to a skilled welder who repaired it for $327.  A new turbo and sensor and cleaning of the radiator , condenser etc. plus much labor came to $5000+.  One positive result was more power and avg MPG from 6.4 up to 7.3.