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C9 engine problem

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marty christensen:
I have an 08 Contessa with a C9 400 Cat engine.  When we purchased this coach last fall in Mesa Az and when we brought it back to Colorado the engine lost power 3 times while cruise control was off and reducing our speed from 65 mph to 23 mph for about 1 to 2 min.  Then we were back to full power.  I took the coach into our local Cat service center and they found codes showing high and low oil pressure and high and low fuel pressure.  The sensors were changed out and everything seemed to be working well.  

On a recent trip over 960 miles we lost power 3 more times, but this time it seemed to be different.  All 3 times the power loss occured while cruise control was off and coasting down a grade, then stepping on the thottle and no power.  This time power loss lasting maybe 15 to 20 seconds while black smoke poured out of the tail pipe.  The coach has been in the service center for 2 weeks and this time nothing shows up on the computer as to any codes or problems.  The service center techs have been driving the coach and talking with Caterpillar and running some tests and have come up with nothing.

Is this normal for Cat engines?  Has anyone else had this problem or one like it?  My last engine was a Cummins and I never had any problem with it.


08 Contessa Rome, C9 400

Richard And Babs Ames:
http://www.catrvclub.org/ The CAT RV club and to links and join the yahoo forum. There are a lot of very experienced CAT owners there. Hopefully they can help as your experience is not "normal" and not electrical as it did not set a failure code.

Gil_Johnson:
Marty,

I'd like to know what they discover.  Your current situation is one I have had with my new to me 08 Contessa with the same engine.  My CAT folks found 2 codes associated with turbo pressure and intake pressure or something similiar.  The CAT manual suggests that these codes where associated with a leak between the turbo and the intake or restriction on the imput side of the turbo.  They checked all fittings and didn't find anything.  They suggested I change the air filter, $185, which I did.  I'll be putting a few hundred miles on it over the next week, so I'll see if it comes back.

Gil

Gerald Farris:
It sounds like Marty and Gil have the classic mechanic's nightmare. That is an intermittent problem on a computer controlled engine that will not set a definitive trouble code and it can not be duplicated on a test drive. On something like that the mechanic has to combine his product knowledge and experiences with you description to determine the problem. For that reason it is important for you to be able to furnish the mechanic with as much detailed information as possible like engine temperature, throttle position, RPM, turbo boost pressure, and environment (outside temperature, elevation above sea level, and terrain).

Sometimes a particular problem with an engine is not the engine, but it is the installation, like the undersized air intakes on the early C 13 engines. I have seen problems like yours occur on a car because the inside liner of the rubber air intake became loose and would occasionally restrict the intake air. I have also seen a sticky waste gate on a turbocharger cause a similar problem.  

If there are several engines that have the same problem, a pattern is formed and the guys at Cat technical assistance will be able to steer your tech in the right direction, but if only one or two engines have the problem, it can be a crapshoot and very difficult to repair.

Gerald  

Jim Gill:
I have a 2006 40' Beaver Monterey equipped with the Cat C9-400 engine...we currently have 40,270 miles on this unit. Last fall as we were returning from the Monaco rally in Tucson we had a similar power loss problem to what has been described in the previous posts. Since our C9 has the pre-2007 EPA emission configuration, our experience with this engine may not be precisely relavent to problems with 2008 and 2009 model year units but here goes.

Our coach had been running fine from Tucson to just south of Monticello, Utah on a late-Saturday afternoon. With no warning, the check engine light illuminated. As most men would do in this situation, I immediately checked the oil pressure and coolant temps as I said absolutely nothing to my wife...I was "hoping" that whatever the problem was would somehow miraculously go away!!! It went out a few seconds later but them re-illuminated. Concurrently, I lost all power and dropped from 65 mph to barely moving along the side of the road at 3-4 mph. On a heavily travelled two lane road pulling a 22' car trailer, finding a spot to get off the road and out of the way was challenging.

I shut the engine off, checked the oil/coolant levels and looked for obvious signs of any problems in the engine compartment, Finding none, I started the engine and it idled fine. It ran up to high-idle with no trouble and the check engine light was no longer illuminated. So I put it in gear and we were back up to 65 mph in no time.

A few miles later, the check engine light came on again followed immediately by another complete loss of power. I saw a turnout ahead and pulled in believing that I had a fuel filter problem. I got out my tools and replaced both fuel filters. Once primed, the engine fired up OK with no check engine light and we were back on the road. A few miles later we lost power again...fresh fuel filters didn't solve our problem. We turned around and limped back to Monticello rather than take the chance of getting stuck on the narrow parts of the highway between Monticello and Moab in the dark.

The ECM fault codes showed low turbo boost, low engine oil pressure and low fuel pressure. The engine would idle fine but no longer would run up to the high-idle point. Calling Cat 800 number only confirmed the nature of the three fault codes which I had already retrieved from the ECM.  Since my Geico insurance was going to cover towing/transport of the mh to the nearest repair facility and Cat warranty was not going to cover a field service call to diagnose and hopefully make this repair in the field, we stayed overnight in Monticello and the next morning put the motorhome on a lowboy headed to Wagner Equipment (the nearest Cat dealer) in Grand Junction, Colorado. We unhooked the trailer before loading the mh on the lowboy...the engine could barely generate enough power to jump onto the trailer and then jump onto the step deck portion of the lowboy.  

After 2-3 days of trouble-shooting, the techs at Wagner discovered that the root cause of this problem was a broken o-ring on the check valve piston in the fuel system that allows excess fuel to return to tank...it was stuck between the piston and check valve housing. The o-ring kept the check valve stuck in an open position causing the fuel pressure to drop below 22 psi...enough fuel pressure for the engine to idle but not enough to run at high-idle under any load. The Cat spec for fuel pressure on this generation of C9 is 55 at idle-75 psi at full load. This low fuel pressure was one of the causes for the check engine light to illuminate and for the engine derations/loss of power. This low fuel pressure also triggered the low turbo boost fault code to be logged .

The faulty check valve is not a serviceable item so it needed to be replaced...the new Cat part number installed was a 294-8620 Regulator Assembly.  All of Wagner's work was covered by Cat warranty...the 294-8620 assembly was only $41.12 but the warranty labor was almost $600.00. Geico paid the $1,400.00 transport charge to get the mh from Monitcello to Grand Junction.

The problems I discussed above may be unique to my Cat C9 engine arrangement but some of the symptoms described by others sound strangely familiar to my experience. Hope this helps somebody else from chasing a disabling engine problem out on the road.
Though my out-of-pocket cost for this experience was $0, the inconvenience and the explanation of this problem to my wife were both priceless!!!

PS Checking the date/engine hour details of the low engine oil pressure fault code confirmed that this fault occurred following the last oil change over a month prior...it had nothing to do with the root cause of the o-ring failure.

Jim

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