Community Forums

H. Miller · 09-11-2012, 06:08 AM

Our 8.3 Cummins is in the shop for some "strange" fuel activity. I've learned a lot in the past several weeks.(not for free). My guess is the MAP sensor circuit. Possibly a loose wire or intermittant sensor.

Vivnme · 09-11-2012, 07:47 AM

Thank you all. We just got to Arizona yesterday. We are going to talk to someone today and will take it in shortly. I will post the outcome when we find out.

Dunner · 09-11-2012, 10:26 AM

Being intermittent, I would re-seat all the electrical connectors several times. Something is telling it to over-fuel or open the waste gate. With the gate open, it won't build the boost needed to burn the fuel.

BFlinn181 · 09-11-2012, 11:54 AM

Quote:

Originally Posted by Vivnme

We are driving a Monaco Camelot. I start the engine and warm it up for 10-15 minutes.

No one has commented on the "10-15 minute" warm up. That is not needed and could contribute to the problem. I agree, the waste gate could be stuck, it needs to be checked for soot build up restricting movement. The $800 check up is the puzzle, how could they not find anything unless it is something that isn't caught by the computer or is intermittent. Dunner's suggestion of a loose connection is where I'd go after being sure the waste gate moves freely.

frankdamp · 09-11-2012, 01:04 PM

I agree with Bob. In the transit agency I worked for we were told to start, check the air brakes as soon as you could, then head out. Idling more than 5 minutes with a cold engine was against the rules.

We would sometimes sit at the station for 6 or seven minutes at high idle, just to avoid the re-start, but that was relatively rare.

Dunner · 09-11-2012, 04:24 PM

Dodge(Cummins) says 5-10 minutes max or the injectors will "coke" from lack of heat to burn off the deposits.

BigSkyBob · 09-11-2012, 05:08 PM

I'm not sure of the model of turbo you have on your motor, but if it's the variable geometry turbo there isn't any waste gate requirement. I would be suspect of the VGT being stuck or worn to the point it's only effective part of the time. Or the signal isn't being received by the turbo to vary the vane geometry.

john50799 · 09-13-2012, 10:09 PM

I also have a 2006 Camelot. The same problem happen to me last winter. Suddenly Heavy Black smoke,no power. What it turn out too be was a plugged air filter although I only had about 7000 miles on the filter.. There is a rubber boot between the filter and intake which was collapsing causing a lose of air. Changed air filter and was good to go after that..If you start the engine and rev it up you should be able to see if the boot is collapsing...Blue or white smoke is bad. Black not so much

Dunner · 09-14-2012, 10:39 AM

You mean like this?

Stretch · 09-15-2012, 07:20 PM

Our dp motor home did the same thing. The coach had been sitting for a few years 2 and when we took it for a prepurchase drive it smoked and had absolutly

no power. Turned out to be a turbo problem. Makes sense. Turbo provides more power. So injectors add more fuel. If the turbo is not working the extra air is not available. So much smoke and no power

tims52ford · 09-16-2012, 06:08 AM

you failed to mention what year is your motorhome, what model engine? is it a cat or cummins, what size engine and how often have you had it serviced. DO you have a vacumm indicator on the inlet tubing after the air cleaner. How many miles and hours on the engine.

num1dgh · 09-16-2012, 07:03 AM

Quote:

Originally Posted by bigdale

Almost sounds like a plugged catalytic converter, on the exhaust. If its gas powered.
If diesel sounds like your Turbo needs replaced. Maybe.

I agree it sounds like the turbo, but that's expensive. For good measure, when was the last time you changed your fuel and water filters?

Stretch · 09-16-2012, 11:45 AM

I thought at the bottom of my post it says what year and what engine, right? Just in case it is 05 HR Navigator with a 525hp Detroit 60 Series engine. And yes It is well maintained with all filters changed on time.. As I said before this was the condition I prepurchased the coach. All was repaired before I bought it. The Turbo was the problem. Actually it was a control on the turbo, a clevis pin which moved the vanes inside the turbo to be more precise. The bottom line is big smoke, bad turbo. An airfilter element would have to be quite plugged to make a bunch of smoke. Most of us change elements way too often