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COMPLETE SHUTDOWN ON I-95
I was heading to a truck stop to refuel after having the bus serviced at Commonwealth Coach. I spent the night at a campground near Fort Lee and early the next morning went to refuel so I could journey home. As I got up to speed after merging on 95 south (just south of Richmond VA) the check engine and stop engine warning lights came on. The next thing I know the bus engine power drops to nothing. I am now a 50,ooo pound glider. Thankfully I was in the slow lane and after turning on the hazard lights I glided onto an exit ramp.
The sad part is that the exit went uphill to the right. I made it to the uphill curve and slowed to a stop. Nice, just far enough to be out of view of traffic exiting the highway. I jumped out and got my reflective triangles and ran down the ramp to let folks know.
After placing the markers it was diagnostic time. Oil pressure was 45, water temp 190, oil temp was good. Everything was good prior to losing power. I called Chuck at Commonwealth and ran thru the situation and readings with him. He recommended I try to start it up. Surprisingly it did. I crawled off the exit ramp and got my bearings on how to get to Chucks shop. I hugged the right lane and sheepishly headed east. After 45 minutes of nervous driving I made it.
Chuck brought out the diagnostic tool and started checking the ECU. It took 2 minutes of checking and he discovered my oil pressure readings were very erractic. jumping from 45 psi to 60 psi and then dropping to 5 psi, back up to 50 and then down to 20. Over and over the combinations were all over the place. Chuck stated the engine has a cut out program when the psi drops below 3 psi. We got the oil pressue transmitter removed and replaced with a new one. Thankfully he had one in stock. As soon as he put it on, the reading stabillised at 60 psi. I asked if we could switch the cut out program to delete the cut out function.
My thought of driving on any interstate and especially I-95 with a bus that could quit/die scared the heck outta me. Chuck went in and reset the program so I’d get the warning lights but I could safely depart the travel lanes and get on the shoulder with power. Much safer.
My Country coach gauges are really not the greatest compared to the gauges that are out on the market today. My oil pressue gauge wiggled a bit but, it always read 45 to 55 psi. When Chuck said the reading were all over the map, I was surprised. I never saw the indications on the gauge. HEck the gauge was reading “in the green” just before the bus died.
Lesson Learned: Get your ECU checked and ensure it does not go into stop mode. In stop mode you have no options. You go from 60 mph to nothing. This could get you killed or wrecked from behind. I highly recommend giving yourself the option to get over to the shoulder with power. Driving on the interstate is hairy enough (those in the DC area & east coast know what I mean).
I really appriciate Chuck and his crew getting me fixed and back on the road.
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18 Replies
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I guess I disagree with changing the ECM’s program to not shut down on low oil pressure. It is there to save the engine from total disaster. I will take my chances on getting off the road if I have an issue. There is also the override switch you can use to limp off. Did you try that?
Next time you have an issue that is real, not a sensor, and you disregard it and have disabled the shutdown, figure on spending lots of money for a new engine.
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Chip,
You should have had between 30 and 45 seconds after the stop light came on…. from what I was told at my PDI they do that to save the engine from destruction and as Mark mentioned I have an override to give you a few more seconds with each push…. but my guy stressed that stop means stop…
Glad it all worked out and it was an easy fix… in my case we spent almost a day on the side of the road… As bad as that was… way better than a new engine.
Bill
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You have a button on the dash for that purpose. It allows you to move to safety.
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I don’t have an overide button on my CC. The only addon I have is a switch on the floor. Not knowing what was going on, i failed to engage it (if it is the override). I still feel safer knowing that when I get the warning lights, I can head over as soon as I can. I can replace an engine but may not survive a rear collision.
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There will be a over ride button somewhere , if you push it before it times out you will have again that much more time to get off road, I would not do that if I were you , I drive 50,000 miles I year and only once ever had to use that feature , sorry you had problems, dial 911 when that happens they will send a trooper to help you!!!!!
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The button on the floor is the override switch on your CC.
and, if you’ve seen video of stopped bus being hit in rear by speeding car, you wouldn’t worry about that possibility…
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There are a lot of features on our coaches that need to be learned and understood by all owners. I may be criticized for the following remarks, but if I am describing you, please try to understand your bus is not a simple car and it requires knowledge and skills to drive safely.
Far too often we hear of owners who have gotten into trouble needlessly. When that happens there could be some risk to their safety, or some unnecessary expense, or maybe just a red face. The complexity of the coaches requires owners to go beyond learning how to find the key. An owner needs to understand and know how to test the brakes and check the air system. An owner needs to know what each gauge is telling him, and how to understand what those gauges should read when everything is correct or normal, and what is outside the normal range.
The problem described above with a faulty sensor is not something a driver is going to be able to diagnose while in traffic or even driving. But the ability to over ride a shut down is something every driver should know so the disabled bus can be safely driven off the highway. A stop engine light may be a false alarm, but whether the problem is real or false the driver only has seconds to find a safe place.
And every owner needs to understand who to contact when there is a problem. Far too often we hear people say the next time they are at Prevost they will have someone look into a generator problem for example. We all own a combination of assemblies, systems and components that share the same place on the highway. The engine experts are Detroit Diesel or Volvo. The transmission experts will be Allison dealers. The chassis experts are the Prevost service centers. The house experts are the folks that converted the coach. A generator was installed by the converter and the converter is the starting point for questions or service.
If you own a coach and don’t really understand how to do a DOT brake check, or if you are not sure what each gauge is telling you, or what the difference between a check engine light or stop engine light is, you need to go on line and download the Prevost owners manual or operators manual for your coach and spend some time reading it. You need to understand how your converter set up your electrical system and what voltages are normal. You need to understand the systems, how they work, what your responsibilities are, and what you can do if something breaks.
Our coaches for the most part are reliable, and when we do have issues most of the time the problems are preventable, or easily repaired, or even owner repairable, but if the owner has not taken the time to learn the basics the simplest things can quickly lead into very serious situations.
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“My Country coach gauges are really not the greatest
compared to the gauges that are out on the market today. My oil pressue
gauge wiggled a bit but, it always read 45 to 55 psi. When Chuck said
the reading were all over the map, I was surprised. I never saw the
indications on the gauge. HEck the gauge was reading “in the green” just
before the bus died.”Chip that is because on your coach there are two different oil pressure sensors. One for the dash gauge and one for the electronic engine control.
Ken
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There have been a couple of times when I’ve pulled off the highway lane due to issues. Both were doggie problem that required attention right now. Spilling a cup of coffee just goes with calling yourself a few choice names.
Not waiting for an exit to come up , found a level area large enough to keep bus on shoulder pavement.
Question …..if you saw a Prevost pulled on shoulder , would you pull over to offer your help ?
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Depends.
If it is safe to do so. I cannot justify stopping a few inches off the pavement because the risk of distracted drivers today is so great there is too much danger.
Add in the fact that two Prevost coaches along side of the road are going to attract attention (Garth Brooks must be driving one of them) and just that could create a second hazard for other drivers.
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If there was a safe way to stop I would absolutely do so and would hope the same if I were stranded. These wonderful machines need a village or at least PC for sure.
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If it was safe would for sure stop , and help out the best I could
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If it was safe to stop, I would stop. Might stop for a short time to see if I could help. Then move the bus to safe location and come back with the toad.
I do the same for racers by the side of the road.
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I apologize for the delay in responding. Life has been hectic as of late.
Getting to the point, I’m red faced about not fulling understanding the floor override switch. Jon was diplomatic in his chastising. Message received about knowing the bus. I have read/studied my cc guide and was fairly confident in operations. Under the circumstances of the breakdown, my confidence is low. This is a Q2 borderline Q3 ( USAF check ride scale).
Things i do:
I do the DOT test as noted prior to each run. I have a note in my checklist to watch the Benny Parson safety video before heading out. Tire pressures, fluids & belts are checked. Awning are verified to be locked in place, all doors and cargo secured. Interior secured, battery charger disconnected, etc following my checklist.
Things i need to brush up on: the prevost xl manual and the CC book. Know the dash 1
Bottom line: For now, I have the ECU set for warnings only, no cutoff. I’ll discuss the thoughts expressed by you folks on having the cutoff with my mechanic and make a final decision.
My prior experience as a FE on C-130s makes me hesitant to allow an engine to shutoff on its own accord. Analyze and take appropriate action. First things first, drive, get over and then take action.
There’s one really bothersome item: I’m pissed that my dash gauge was BSing me. CC should never have taken out the prevost dash and put in their own version.
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Chip, don’t be too hard on yourself, you’ll sort it all out and we’ll help.
We couldn’t find the transponder on a C-130, you can….
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