I had just filled up our mh with 70 gallons of fuel, from the Pilot truck stop in Madera CA.I Drove to Stockton, with my daughter's in-laws following in their mh. When we arrived, I was told the mh was blowing black smoke, (more than usual) but only when we went up overpasses, all the way to our destination. I had not noticed any black smoke, nor had had I noticed any appreciable difference in performance, or fuel mileage. The MH ran good as always on the trip homeJust in case, I changed the fuel filters this morning, and cut the old filters apart, I saw nothing inside like allege, or any dirt.I'm wondering if I should take the mh into Cummins West and have them check it out, or just wait and see what will happen, the next trip out.As a side note, the wind was probably blowing @ 8 - 10 mph of head wind, and pulling a 24 ft. enclosed race trailer weighing 6000 lbs.

Maybe your turbo?Brett is a good diesel guy. Maybe he will read and respond.

I was under the impression that the turbo either worked or didn't.If I'm wrong then maybe this could be the problem.By the way, I should have included that this an '05 Monaco Dipolmat with a 400 hp 8.9 cummins engine and a 6 speed Allison transmission.The mh has about 44000 miles.

How long since you checked the air filter? Also, if the exhaust brake was sticking in a semi closed position, that will cause black smoke.

Doug E. wrote:I was under the impression that the turbo either worked or didn't.If I'm wrong then maybe this could be the problem.By the way, I should have included that this an '05 Monaco Dipolmat with a 400 hp 8.9 cummins engine and a 6 speed Allison transmission.The mh has about 44000 miles.There is some sort of a turbo controller, a waste gate valve, so that it maintains the proper pressure.

EGT = Exhaust Gas Temperature. The higher the temp the more black smoke and the hotter the turbo and then the repairs begin. Something is overheating.

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28 Replies

Doug_E_
Explorer
May 26, 2013
Hi Ken,
I had purchased and used the PacBrake oil before.
When I talked to Dave at Cummins West, he asked if the MH had set for awhile, when I told him it was not in service for 3 months, he said sometimes the PacBrake will stick for awhile.

Hi Brett, thanks for the link to the page on lube points on the PacBrake, I believe I had lubed all of the points but I'm going to recheck in the morning.

Thanks again to the forum and all who responded with suggestions of help.
wolfe10
Explorer
May 25, 2013
n4hwl wrote:
Doug

What did you oil the exhaust brake with? I think I read that you are suppose to use some type of high temperature oil on it. I bought some Pac brake brand oil somewhere that was for this application. It may be all advertising about the pac brake oil. I thought I would just ask.

Ken

http://www.pacbrake.com/index.php?page=maintenance-2
n4hwl
Explorer
May 25, 2013
Doug

What did you oil the exhaust brake with? I think I read that you are suppose to use some type of high temperature oil on it. I bought some Pac brake brand oil somewhere that was for this application. It may be all advertising about the pac brake oil. I thought I would just ask.

Ken
Doug_E_
Explorer
May 24, 2013
Ok, for what it's worth.
I must have scared the heck out of her, (was going to leave her all by her self all weekend at Cummins West).
Hooked up the Jeep and was headed into town, to have her checked out.
On the way there, I noticed a different exhaust tone, then she started running just like always, 32 lbs. of boost too.
The only thing I can figure, the exhaust brake must have stuck part way closed.
Anyway, it's nice to have her running on all 6 again.
Thanks for all of your suggestions, never know one of them might have helped.
Doug_E_
Explorer
May 22, 2013
The check engine light never came on.
Other than a little slower take off from a dead stop, and some black smoke out the exhaust pipe, I think she still runs great.
When I find out what the damage is, I will post here.
keepingthelight
Explorer
May 22, 2013
Did your check engine light or ECM light come on indicating a problem?
May want to have that scanned first. If you are sure your boost has dropped slightly, this could indicate a bad injector, loose turbo hose or an issue with the turbo or exhaust brake staying open. Better have Cummins troubleshoot, we are only amateurs;)

Keep us posted
hone_eagle
Explorer
May 22, 2013
Doug E. wrote:
If I recall correctly, the boost guage used to register 32 lbs. of boost, now its hard pressed to reach 24 lbs, of boost.
I've tried everything, all of the members on this forum have suggested.
I think it's now time for some professional help.

You did all you could do ,the black smoke is fuel injected into a insufficient supply of oxygen
if there is no discernible hose or boot leaking you have to consider the CAC is losing pressure,
could cost a bit.
aztortuga
Explorer
May 22, 2013
Doug, do let us know what the diagnosis and outcome is.
Doug_E_
Explorer
May 22, 2013
If I recall correctly, the boost guage used to register 32 lbs. of boost, now its hard pressed to reach 24 lbs, of boost.
I've tried everything, all of the members on this forum have suggested.
I think it's now time for some professional help.
tinkerer
Explorer
May 22, 2013
One other thing to check is the connections on both sides of the turbo. Does this coach have turbo boost pressure somewhere in the instruments? I have a Freightliner chassis and you can scroll through the reading on the instrument panel and it will bring up the turbo boost. I use it all of the time as with this reading I can tell how much load the engine is under. ;)