New Bus Owner....now it wont start :(

[Seangie]

Hello All, 

We went all in and bought a bus.  1984 Eagle 10S with a 6v92t.  Drove it home before Christmas and then we left for vacation to florida and had a great time at Arcadia.  Unfortunately we did not get a chance to register the bus and get a toad setup before we left so we went in a van w/pop-up and the kids.  Awesome time at Arcadia.

So I get back this week and go out to start the bus from the cockpit and it cranks but wont start.  It is a bit chilly here today (40) so I start up the generator and plug in the block heater.  I wait about 5 minutes and start the engine from the back and it starts right up.  Smokes a little (normal) and then right about the time the smoke usually clears she stops running.  I try starting her back up again and she smokes a bunch and cranks and cranks but never turns over.  Any ideas?   Thanks!

-Sean

[Oonrahnjay]

It hasn't been cold enough here (I'm assuming the bus is in Wilmington, is that right?) to be gelled fuel but it sounds like a fuel starvation problem.  Is the cutoff valve back in the "full run" position?  Check with someone who knows the 6V92 engine and find out if there is a fuel cutoff and/or an air cutoff.  If the engine has either one and it's set in the "engine off" position, your engine won't start.

But the run-for-2-minutes; stop-and-won't-restart is really classic fuel starvation.  First thing, check the fuel filters.  If there isn't fuel in the filters, that shows you that you have a fuel problem.  If that's it, look at if there's enough fuel in the tank (some tanks won't feed the bottom 10-15-20 gallons), the pickup tube in the tank is clear, the fuel lines aren't collapsed or blocked, and that you don't have any air leaks.  There are techniques to pull fuel from the tank through the filters and into the engine-driven fuel pump and then prime the pump through to the injectors, but I don't know about these because they're different for the 6V Detroit Diesels than for my engine.

Oh, also, it might have been cold enough here for free water in the tank, lines, or filters to freeze into ice.  As long as you're disassembling the fuel filters, it won't be any significant additional work to check the filter medium and clean the bowls to be sure that that's not the problem.

I hope that someone who has experience with your engine and bus can help you.  It sounds like something simple to me.

[Seangie]

Oonrahnjay,  (Wilmington is correct)

I checked the fuel cutoff and it was in the full run position.  Not sure about an air cutoff.

I thought it would have been fuel.  I checked the filters and they were both a little more than 3/4 full.  There should be enough in the fuel tanks, half full.  Pretty sure I don't have any air leaks.  It stays aired up for a few hours after turning off the coach.

The first time I started it...I didn't think about it but I pulled the key out of the ignition to open a bay door and then went to the back to start it.  It did start right up and then died after about a minute.  After about 20 minutes I remembered that I didn't have the key in the ignition in the on position.  So I went back up, put the key in the on position and then tried to start from the back again and it started up and ran fine (about 10 minutes) until I shut her down. 

I am assuming the key being out of the ignition is what the problem was.  Does it seem strange that it started up the 1st time and ran for about a minute without the key in the ignition? 

Hopefully that was all the problem was.

Thanks for your help.  Good stuff to know.

-Sean

[gus]

I know nothing about Eagles but this is a classic case for a GMC which has had the rear engine run switch accidentally turned off (easy to do) and shuts off the engine once air pressure builds up.

[luvrbus]

Turn the key on up front when starting a Eagle from the back no air shut off on a 6v92TA engine

good luck

[Oonrahnjay]

   Sean, not to belabor this too much but when we say "air leak" in regard to a fuel system, there is something you should know.  On a car, you'll have a fuel pump in the tank and if there's a pinhole in the fuel line, you'll see fuel dripping or spraying from it.  On most buses and trucks (and even a lot of diesel cars - my VW diesel is this way), the only pump is on the engine and the fuel is pulled out of the tank, up the fuel lines, and through the filters by suction -- on these vehicles, if you have a pinhole in a fuel line (or something like a filter cover that's not seated right -- any kind of leak), you'll have air leaking INTO the fuel supply section.  If you think, "I'll check for fuel leaks", you don't look for raw fuel, you look for places where air is leaking into the fuel system.  In fact, there are so many places where air can get in, it often more a matter of deduction ... "I keep pulling fuel into the filter and up to the pump, but it keeps bringing air foam up instead of fuel", that's a sign that it's worth a look for an "air leak" INTO the fuel system.  And an air leak into the fuel system will stop you dead in your tracks, so it's something you always need to think about if you're having fuel supply problem.  (Not the only thing, but something to think about.)

[pvcces]

Sean, you say that your engine smoked a bunch when you were trying to start it, but it would not turn over. That's impossible as it would not smoke if it was not turning. I assumed that you meant that it would not fire up and run normally.

These diesels fire entirely by compression, so if they have enough fuel and enough air when you crank them, AND the compression is high enough to fire the fuel for the ambient temperature, they should start.

Since you have had a start symptom before and the engine ran since, I doubt that anything major happened to it. Most cases of failure to start are because one or more of the conditions in the above paragraph has not been met. This time of year, it's usually not enough heat to fire the fuel. You know that there is at least some fuel, but you are not getting any firing of the fuel. This can happen if the engine cranks too slow because the heat of compression is lost before it can fire the fuel.

A lot of the turbocharged two strokes do not fire well at temperatures below 40 F. A block heater used for an hour will often make them start like it was summer outside. Also, high elevation can make the compression too low like cold weather does. It takes the same cure if that is the case.

Some people just use a really small snort of ether to get them going when cold. It's risky to do because it can be really hard on the rings. Adding heat is the safest thing to do. Up here in Alaska, I just unhook the air filter and wave a weed burner near the air intake if I want to get a stubborn engine going.

Good luck.

Tom Caffrey

[wg4t50]

Sounds normal to me, with the "Key" off, the air stop solenoid needed air pressure and the key on to stay in the rin position, it started, when the air pressure came up, it shut down, all normal.  Takes a little sperience to keep head right.

[white-eagle]

i got to get a word in about this  .
when i first got my bus, i had to change a hydraulic pump.  after installation, i wanted to test it for leaks and thought i would just "jog" the engine with the back start button.  Since i was in an enclosed garage, i didn't want it to start.  Lo, and behold it did, as i ran around trying to figure out how to stop it for the next 5 min.  Then it stopped by itself.

after i posted, i found out all DD's start without a key (also got another minor lecture when we were putting flywheel back on cause it could have cranked enough to start), and they stop when enough air builds to shut them down if the key is not on.

At least you found out the easy way.

Nice meeting you and the family in Florida

[buswarrior]

before messing with anything, back to basics, build yourself a priming rig of your choice, and re-prime and get it to start.

You'll need a priming rig for the future anyway, so no time wasted there.

It might start, run and never have a problem again?

And don't worry about why, you just chalk it up to the bus gods having played a little trick on you, and then showing you a little mercy.

Don't go looking for trouble, just get it to run.

happy coaching!
buswarrior

[tomhamrick]

Hi Sean, I think you found your own problem. If the air presuure is built up the bus will not crank from the back with the key turned off. If there is no air the bus will crank from the back with the key turned off but will shut down as soon as the air builds.

Tom Hamrick

[papatony]

both filters have to be complety full before the pump will pick up the fuel

[gus]

Tom,

When the engine shuts down and loses air it will start with the run switch off and can't be stopped, except manually at the governor, until air pressure builds up.

If there is enough air to operate the shutoff valve it won't start with the Run switch off.

[DMoedave]

Hey Sean, glad you got it figured out. I will try to explain my priming utensil that i have and boy did i need it this trip. (you might have seen my engine bays up and open most of the rally) i have a 1/2 flare nut that fits my filter shutoff valve just before the primary. It is on a 3/8 copper tube which i soldered a 5/16 copper line that fits inside of it and did the same with a 1/4 line and it slides into a fuel line from a outboard motor tank. i slide the suction side into a 5 gal diesel can and undo my line to the filters and attach the primer and pump it up nice and tight, close my ball valve to the filter, switch back to the tank/bulkhead line and start her up. The engine start switch is great for this.

I got such a kick out of your one son, i swear he looks so much like my little brother did when he was a kid. good luck with your new coach. dave

[artvonne]

Tom,

When the engine shuts down and loses air it will start with the run switch off and can't be stopped, except manually at the governor, until air pressure builds up.

If there is enough air to operate the shutoff valve it won't start with the Run switch off.

  And here I thought I knew what I was doing. So let me get this straight.

  Cold airless bus will start from the back with the master switch off, build air in which case the fuel shutoff will engage, and then it will quit?? But until that time you cant shut it off?? what if you push the manual stop lever over to the stop position??