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US07 MP7 excessive black smoke

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Hi all, hoping for a little advise here.

I'm working on an mp7 with excessive black smoke. Good power, runs fine, no boost leaks, just loads of black smoke under acceleration. Even stomping it in neutral will get a good puff of smoke.

No dtcs. I've checked egr valve movement with vcads, compared boost, mass air readings to another truck of same engine. All readings are pretty much the same.

It acts as if the egr valve is leaking/not closing all the way but I was hoping for another opinion or 2. I sure wish there was a way to block the egr off to verify before I go ripping her apart.

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how do you know you have no boost leaks black smoke indicates lack of air Hows the air cleaner????

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Pull the egr tubing off between the egr mixer and venturi, unplug the egr valve.  While at an idle there should be little if any flow from the egr valve. With your hand over the venturi outlet, you should not feel any pressure. 

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Could also have a stuck turbo

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If this has only just started to happen make sure no little friends made your air cleaner into their house over night even if it has gradually started to happen on a older motor I would say the air cleaner is blocked dunno about these flasher newer ones 

 

Paul

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You can also try cleaning the ports and tubes to the differential sensor on the intake manifold !

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Ok removed egr pipe and fabricated a plate to block intake pipe. Still dumping the smoke but at least I've eliminated the egr valve.

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If it still has a DPF, drop it out and confirm its toasted. No soot should pass thru the filter, not enough to be visible. I'd bet money it's dusted.

Unplugging the egr valve and ziptying a rubber glove over an egr tube (I use the cooler outlet) will confirm a failed valve, which rarely sets a dtc but may cause a rough idle.

The EGR valve leaks brand new out of the box, but the glove will explode if it's bad.

Assuming you can get to specd boost at 100% engine load in 2nd highest gear, consistently, it could also be injectors, less likely a turbo, manifold leak... Etc. the us07 mp7 had issues with valve train too.

Being the dpf is cooked, I'd start there.

Sent from my iPhone using Tapatalk

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Ok found the problem. Thanks everyone for the suggestions.

I started pulling injectors looking for a cracked tip.  The injectors looked awful new so we ran the part number and someone has put mp8 injectors in it. This truck runs all over the country as part of a fleet and rarely had the same driver in it so I guess that's why the company didn't put 2 and 2 together when the smoking started.

So now I'm putting a cup and injector kit in it.

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Good catch on that. It's little things like that that will have you pulling hair. 

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Yeah, I was starting to stress over this one. Nothing like tossing a few grand in parts and then explaining to the customer why it's still not fixed.

Luckily I only had roughly 10 hrs in it before I found the problem.

Thanks a bunch!

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