09 prostar cm871 blue smoke from intake tube

[Sjplcjd1]

I realise a few people might hammer me for this post. I have watched so many Rawze videos my wife might be getting jealous hahah. Went through the forums. Im just needing a starting point.

2009 prostar cm871 615k. Here's the run down this truck had another driver in it about 12 weeks. Prior to maybe 1 gallon between 12to15k oil changes. About 6mpg. Upon returning it is at 4.5 mpg and 3 to 4 gallons between changes. Along with a laundry list of other ticks from just being beat down.

I drove the truck twice Dallas to Austin and back to verify it and see how it ran. 1k miles lost about 1/3 gallon and at 60k loaded with a van and empty back I stayed at 5.1mpg. On the pump not the dash. No smoke at idle but the trailer was covered after the 2 trips. In fairness this is a mid roof without the cap and I pulled a van.

I used a combustion block tester(fluid and bulb pulling air from the overflow) and it tested good. I did it thrice just in case.

So I see no smoke at idle, pull the air filter to check it and listen to the truck idle a little better. And out trickles blue smoke. Not a cloud but a constant and consistent stream. Personally, Ive never it before. 615k and it its the original turbo. No obvious failure oil leaks in piping, seal, power loss ect...

My first thoughts oh turd the dang valves are leaking. But that's a long way to leak back. And why wouldn't that smoke be getting sucked back in to the motor. So in theory I believe it is when im rolling hence the trailer getting covered. I don't think valves but maybe turbo. However im not a great mechanic. And this is theoretical. Has anyone seen or heard of this. Or have other theories. Im trying to figure out where the heck I should start.

Truck smooths out when the magic plug is pulled. Egr tune coming and due. But, I would really like to get to the bottom of the oil consumption first. Truck lived a pretty good life prior to the last 40k

[tree98]

Your saying the smoke is coming out of the air filter housing while the engine is running? And your also saying that this truck has a fully functioning emission system and is running fine while pumping out enough smoke to turn the trailer black?
Are you using the truck with the "magic plug" pulled?

[marek4792]

This almost sounds like the EGR valve is stuck open or leaking in the closed position, it could explain the smoke coming out of the intake at idle where there isn't enough intake pressure for the gas to be pushed into the engine. Just an idea that mpg is low even if you're running 70+ I'd do an EGR tuneup and clean up the EGR circuit and monitor the oil consumption.

[Magard]

Sounds like running stuck open egr valve for a while. Carbon packing the rings. Probably explains oil consumption.

[tree98]

But no CEL or derate?

[Nilao]

Nah, I've seen them stuck open about 25%and not throw a code

[Rawze]

Assuming for a moment you are not loosing the oil because of external leaks...


he also needs to pull the DOC and DPF and take pictures of their faces,.. post them here...

while they are off,. have both of them baked and flow tested. I would have a good bet that the DPF was cracked and causing issues if the trailer is turning black.

Also with that much oil consumption, there will be no absolute way to keep them operational. They will continually clog and fail because of face-plugging due to all the oil consumption.

Did you remove the oil fill cap and see how much blo-by it has coming out of the oil fill tube?

And,... When was the last time the crank case filter was changed?- high oil consumption will cause the crank case filter to clog up rapidly too. AND a clogged crank case filter can cause blo-by issues and turbo failure problems. - Most people resort to drilling it out or replacing it with a maint. free filter as their engine gets older to combat this...
http://rawze.com/forums/showthread.php?t...376#pid376

A full EGR-tune-up + clean out the EGR valve and ensure it is not getting stuck,.. etc.etc.

Also check the EGR Delta-P tubes for clogging, as well as the cross-pipe for the exhaust back-pressure sensor.

Also pull the CAC pipe off between the CAC and intake manifold and ensure it is not wet with oil due to the turbo slobbering excessively.


You also need to ensure the person you let drive it did not put a different program or something in ecm.

[Sjplcjd1]

I feel bad I forgot to update everyone on this truck. It stayed on the back burner for a bit.

Found out the truck went 40k miles without an oil change. I'll start there. Did the egr tuneup it was caked I mean caked with soot. Manifold down to a straw of a hole. Cleaned everything out. Found a hairline crack in one of the doc bunks. Welded it up. Egr was tight I was convinced it was sticking but didnt know how to prove it. I replaced it instead of trying to clean it out. Put it together sounded much much better. Found a leak in the gasket between the turbo and the manifold.
Dropped the oil did an oil change. Black as night. I have detroits and this was way way darker and thickening. Took it to a shop here and had a forced emissions cleaning done. I forget the actual name but I can look it up if anyone needs. They also run an oil treatment and drop the oil again. This eliminates about a half pound of soot without baking the filter but more than that checks for leaks. Everything was snug. Truck is running better than when I bought it at 280k miles. I have only done a few small trips truck sits for the most part today. I put only 800 miles on it. No blue smoke no smoke on the trailer. Truck did around 6.8mpg texas about 67mph and no codes. I am on my original turbo so this may be coming soon but no slobber.

[Sjplcjd1]

Replaced crankfilter with maintenance free and no oil consumption. Forgot to mention that. I still dont understand what would have been causing the oil consumption though.