Air Shut off

ArtGill · April 23, 2017, 05:23:57 PM

Would a 6V92ta DDEC II 1989 have an air shut off? I had started my coach, built air, and started to pull it out from under it's shed and then heard a loud snap and the engine shut down. Tried to restart, it would try to start but wouldn't catch on enough cylinders to run. Also showing black smoke. It didn't react to either. I had the alternator replaced about 100 miles ago.

Thanks, Art

luvrbus · April 23, 2017, 05:49:38 PM

Sounds like it snap the blower drive shaft

Geoff · April 23, 2017, 06:43:12 PM

Humm.... A "snap" and the engine shut down, and black smoke when trying to start afterwards does not sound good. Something broke, and it doesn't sound like a DDEC problem.

Is the alternator mounted on the back of the engine (gear driven)? If so, it has to be aligned when installed. This is TOTAL speculation, but if the alternator was not aligned and forced on, the "snap" could of been the alternator drive breaking and falling into the geartrain.

--Geoff

luvrbus · April 23, 2017, 06:57:54 PM

Is the alternator mounted on the back of the engine (gear driven)? If so, it has to be aligned when installed. This is TOTAL speculation, but if the alternator was not aligned and forced on, the "snap" could of been the alternator drive breaking and falling into the geartrain.

--Geoff
[/quote]

I hope that is not the case this guy is looking forward to a trip of his dreams to Alaska

ArtGill · April 23, 2017, 07:07:14 PM

Yes, The alternator is gear driven. I only heard one snap. The DDEC did check good but I will not receive it back until Tuesday. The blower shaft is my inexperienced guess also.

So, I don't have an air shutoff?

Art

luvrbus · April 23, 2017, 07:33:37 PM

I never saw a air shut off on a highway use 92 series you see the emergency air shut off on some off road 92 series like on drilling rigs.You shouldn't have it on the NJT Eagle

sixtyseven · April 23, 2017, 09:25:38 PM

Mine did something very similar once. It ended up being the circlip that holds the blower shaft in fell out and let the shaft slide out of it's splines. Once I slid it back in and put a new clip back in, it fired right up.
Also if I remember right there is a fiber coupler in there that could have broken. Take the cover off the blower drive next to your alternator an check it out.

daddysgirl · April 24, 2017, 07:33:06 AM

I remember the conversation, but did you replace the 50DN or did you replace it with a smaller one?

I'm not pretending to know anything, but I have another question.
You started it, it built air, and you heard the "snap" when you put it in gear? Did you have the "not gen" light?

Cliff...is there anything that would cause a snap like that when going into gear?

I'm only trying to think from a different perspective...no offense intended.

luvrbus · April 24, 2017, 08:10:53 AM

The blower shaft drives the power steering also on a Eagle I seen the shaft snap on cold days from the power steering or all the springs break inside the coupling

ArtGill · April 24, 2017, 05:28:51 PM

According to my manual, the Alternator is run off the same gear/shaft as the blower. I haven't confirmed this yet. I have contacted my local, longtime Detroit Diesel Mechanic, who has done 2 stroke work for me in the past. I am expecting my DDEC tomorrow and I will plug it in and see how lucky I am. The DDEC shop didn't find anything wrong with it.

Daddysgirl, I already had it in gear and moving slowly, but moving.

Thanks Everyone, keep your fingers crossed for me.

eagle19952 · April 24, 2017, 05:54:29 PM

Quote from: luvrbus on April 24, 2017, 08:10:53 AM
The blower shaft drives the power steering also on a Eagle I seen the shaft snap on cold days from the power steering or all the springs break inside the coupling

in the oilfields north of Santa Claus ... we switched every manner of power steering reservoir to 0w30 synthetic...solved the cold problems

luvrbus · May 03, 2017, 06:57:11 AM

Any update on the problem and cause yet ?

ArtGill · May 04, 2017, 06:47:49 PM

Still an answer. But here is where we are. We removed the power steering pump that is driven off the same gear as the blower. We took the retainer that transferred power from the gear to the blower shaft and pulled the blower shaft out. The shaft was good, the transfer coupling was good and when you turned the blower shaft with your fingers it had a little resistance. When we bump the starter, the blower gear turns. I had a marine diesel mechanic come over for his review. He agreed that the blower shaft felt like the blower was turning. He removed the exhaust pipe from the output of the turbo looking for the remains of broken valve. None found.

The mechanic's suggestion is to remove the Valve covers and look for damage. Then take the Turbo off and confirm the blower is turning.

But first I'm going to stick the exhaust pipe back on, turn on my electric fuel pump that is for priming and see it that makes any difference just eliminate a fuel problem. I don't think fuel is the problem, too easy to check.

Any ideas or suggestions are welcome.

Art

ArtGill · May 11, 2017, 05:32:38 PM

Good News and Bad News.
Good News, my engine is running. We tuned on my fuel primer pump and the engine started. We then turned off the primer pump and after about a minute the engine quit. We had only been running the engine at idle speed. We then replaced both fuel filters turned the primer pump back on and the engine started. This time I did run the engine at higher RPM's and when we turned the primer pump off, the engine continued to run. So the day the engine quit, did I lose prime for some reason?

The Bad News is I don't know what caused this.
I think I have plenty of fuel, unless stolen, and it is in the same place where the engine quit.

When you don't know what you did to fix something, it leaves you uneasy.
Art

Geoff · May 11, 2017, 05:50:06 PM

It is the blower "quill shaft". They strip out and will work on and off. You must have the 48 spline shaft on the quill shaft. The updated ones use 24 splines and they never strip out. To fix the engine you have to pull the blower off and replace the drive to 24 spline drive, and pull the back side of the blower side off and change that side also to 24 spline. Easy enough, (LOL), but if you have something that is driven off the back (like a power steering pump) it makes it that much harder to replace. The other alternative is to pull the blower and if the quill shaft is only stripped on the blower side you can just keep using the 48 spline shaft changing out the shaft and the blower drive for new. it will out live all of us.

--Geoff

P.S. I don't know what you heard "snap", but it wasn't the blower drive.