Just brought Tink Hardaker's coach home. It ran GREAT, except twive on the trip, as we were slowing down, the engine suddenly stalled out, once at about 40 mph and the second time at about 10 mph. It also refused to crank once. (not even a click as I turned the ignition key). When we waited a minute or two and tried to restart the engine, it cranked right over. Both instances occurred when the engine was warm. Oil pressure was at least 40 pounds, temperature was normal. The coach has a cummins 5.9 diesel with a 6 speed Allison transmission. Any ideas? Thanks, Rick

Check & clean battery cables at battery and at ground. Also check hot cable to starter. Also does it have computer control?

I am not the expert around these parts however, these Cummins diesels and I am sure yours is the same has a ton of safety features, so that if this fluid is low, or that temp is high it just cuts of. This is because you can blow one of those engines in a second. I am sure you have computer diagnostics on your coach, it would be worth a trip to your Onan/Cummins, I think they now call themselves N/Power to have a scan.

I know a couple who had a coach just like yours and they had a similar problem but since it always started up they delayed taking it in because of schedules etc. After taking it in they were very happy they did so.

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Most newer Cummins are designed to shutdown for low coolant - low oil - engine overheating complaint. It's the motors way of protecting itself from driver abuse.

Most company truck drivers will drive there rig until the last bolt falls of his truck. For Cummins it means less warranty and for the trucking company it means less major rebuilds. It's alot easier to pay road service to fix a coolant hose then to tow a truck and rebuild the motor.

The condition you describe sounds more like a loose or corroded cable. The second place I would look would be fuel delivery. The lack of even the starter not turning over tends to make it a cable connection of some sort.

If you run the coach and shake some wires by the starter, battery and frame chances are good you'll find your problem. Anything else would require a test light while it's happening.

Pluging in a scan tool will only bring up historic trouble codes if you have already turned the key off. Your flash codes will tell you about anything that has ever happened to the engine since it was new or last cleared. It could show up as low oil psi if the engine oil was changed and the filter wasn't refilled. Low coolant if someone had the key on while listening to the radio and changing the coolant or hoses.

If you have someone plug in a scan tool insist on clearing out your historic codes. I own several scan tools and you can find some really cheap ones on Ebay. I got one ProLink for $20.00. You could expect to pay about 100-300 dollars for a decent one on Ebay. Get a ProLink with a HD Standard cartridge. Anything more is overkill for an owner operator.

I will be selling one on Ebay used in the next day or two. If you find one that has more cartridges then you need just resell the extra stuff back on Ebay. Do not buy a scan tool if you have a mechanic diesel motor, this is only for electronic engine controls.

There are only two reasons for a diesel to shut down: No fuel, and/or no air.

The most liklely candidate for your problem is $23.00 (at any auto parts place) part known as the constant power realy. It turns on and off with the key and energizes the fuel selinoid. I’ve changed mine about two years ago and it’s intermittent again.

Also, change the fuels filters. Both of them…one is hidden very nicely under the alternator.

By the way the engine will crank all day but it won’t run with this condition.

When the engine shut off were the warning lights on or off...this will give you a clue.


[This message has been edited by eric (edited November 21, 2005).]

It takes fuel and air to run a diesel. If you have and electronic control diesel then it needs electric to keep the fuel plunger or shutdown solenoid open.

They stated that it wouldn't turn over, not even a click, so to me it sounds electrical. The fact that it only started to die down when they slowed down sounds like it may be sucking air into the fuel but that wouldn't explain the lack of cranking so I would still check the electrical system.

Change your fuel filter anyways... couldn't hurt.

I have seen many of ways that a diesel has shut down that is not fuel or air related. Electronic engine controls or ecm failures, coolant leaks, Hole in the side of the engine block and my favorite... turbo seal blowing.

Warning: Turbo diesel owners wanting extra sleep do not read below!

When a turbo seal leaks motor oil into the intake and the turbo whips it into a foam the oil drops are then running the engine (compression ignition) and nothing but a lack of oil or a kaboom will shut it down. The motor will over rev and it will sound like NOTHING you have ever heard before. I have seen this happen many of times!

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[This message has been edited by Bill (edited November 21, 2005).]

If you do a search on "Diesel Ignition Problem" you'll find a discussion of a similar problem on our 94 Breakaway with a Cummins (Aug. 29, 2004). The symptoms sound very similar.
Stu Allen

https://www.barthmobile.com/ubb/Forum4/HTML/000730.html

Just to make it easier...

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Have you had the coach worked on at Banks Power? If so, check to see if the fuel filter attached to your intake manifold fell off....sorry, I couldn't help myself. 1C in Minn.? Brrr!

quote:

Originally posted by hilarlee:
1C in Minn.? Brrr!

That's like 34F. We have already hit 20F.

I've had 3 service calls for air freeze ups already. Brrr!



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Just cleaned 1+" of snow off the wifes car so she could go to work. The lawn is white but streets are clear. Now its time for me to go out in it for a day of driving. JKB