General Boards > Technical Support
C9 missing
Richard And Babs Ames:
Something I just thought of is our first injector failure only occured when the engine was under load and hot. The injector would function properly when cold and not under load.
Our engine a 3126B cools when using the exhaust brake so I did not mention it earlier.
Ken Sair:
Update. Took the ol' girl to Johnson CAT in Riverside today. Explained situation and they had at it. Cylinders all check OK so its not a fuel injector. They performed an exhaust brake test and that was Ok also. Then checked the exhaust pipe outlet and all was OK. They were unable to duplicate the missing I experienced after extended downhill runs with the exhaust brake on. We discussed fuel pumps/fuel filters/cold starting etc. Very helpful folks.
They did venture an opinion though inspite of only 3 occurences in 11 months. Johnson CAT believes that extended downhill (one was 13 miles of 6% grade) exhaust braking was causing the brake to heat up and thus expand, if only a tiny amount. Then at the bottom, when throttle was necessary the brake would 'stick' partially closed. Then when I shut it down for 30-45 minutes it had time to cool down thus 'shrinking' to normal size and operated properly. It did work on the way to the shop but exhaust braking was limited to offramps etc. Being unable to duplicate the problem, I said thanks, handed over my $250 (they cut me some slack as they had it a little over 4 hours) and returned to the campground poorer but not much wiser. I did get the most recent CAT flash update for no charge. Tech said he felt guilty charging me for the computer running while he was checking other stuff. It had to do with fuel management of something.
So, tomorrow I call Jakebrake and pick their brains.
Ken Sair:
Spoke with Jakebrake today. They dont believe the brake assembly itself is the issue. We all are convinced it is not an engine issue. They also didn't buy the metal expanding after extended use as things actually cool down because the engine fan engages with brake usage.
Jakebrake feels it could be one of two things, the solenoid itself (which can be activated electronically at the shop and help closed for 15 min) or the air cylinder itself (air on-spring off). Need to take it back to CAT. Crap. Wished I'd have known this wednesday as I could have had themk cover all this under the 5 year warranty. They also asked if the 3 episodes occured after switch disengagement or throttle disengagement. I had no clue. I'll pay more attention. If it turns out the be warranted i'll address the $250 from last Wednesday then.
Anyway, I'll continue to monitor until late April when I take it to Holt CAT in San Antonio for the lash valve adjustment. I'll have them check then. Problem is not many long hills between here and there to duplicate problem.
Any, thats what I know.
Bruce Benson:
Assuming you are coming east on I-10. Take 70 east out of Las Cruces, enjoy a day at White Sands; take 82 east out of Alamogordo, enjoy a cool night in the pines of Cloudcroft; take 285 south at Artesia, enjoy a day at Carlsbad Caverns; join back up with I-10 at Fort Stockton.
You will add 2 nice long grades, 90 miles to your trip, avoid El Paso and enjoy some great natural wonders!
Jerry Pattison:
Geez, can I relate to this! I have a 98 Marquis with a C-12. My experience was similar but different. I had some instances of the engine "missing". I thought at the time, how can a diesel engine miss? Anyway, it got worse, so I called Cat, went to Cat service, they thought it was maybe engine mounts making the engine seem like it was missing, etc. I discovered that it was missing more on right-hand turns (as up a highway). Went on for months!
To shorten the story, it turned out to be a fuel temperature sensor that was intermittently shorting out the 5 volt supply to all those engine sensors. So, for just milleseconds at a time, the engine sensors shut down, then came back on. But, in my case, only in right turns.
Seems that the way that the cabling was tied together led to stress on the wire in right turns, leading further to a shorting of the 5 volt wire at the fuel temp sensor.
It took months of search, and only once I was able to get a service supervisor to ride with me and have the failure while he was in the coach could we prove to him that there was really a problem. Fortunately, during this ride it failed and continued to do so while we pulled into the service bay, left the engine running, in gear, while the computer was attached, and the analysis found it.
So, my message is, it is likely a simple solution, mighty hard to find, though! Cut all those tight cable ties around the engine sensors! Chuckle!! And mention this forum to the service guy!
Good luck!
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