steeler Posted June 3, 2016 Share Posted June 3, 2016 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. Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/ Share on other sites More sharing options...
fjh Posted June 3, 2016 Share Posted June 3, 2016 how do you know you have no boost leaks black smoke indicates lack of air Hows the air cleaner???? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-335322 Share on other sites More sharing options...
turckster Posted June 3, 2016 Share Posted June 3, 2016 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. Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-335323 Share on other sites More sharing options...
fjh Posted June 3, 2016 Share Posted June 3, 2016 Could also have a stuck turbo Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-335328 Share on other sites More sharing options...
mrsmackpaul Posted June 3, 2016 Share Posted June 3, 2016 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 Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-335342 Share on other sites More sharing options...
fjh Posted June 3, 2016 Share Posted June 3, 2016 You can also try cleaning the ports and tubes to the differential sensor on the intake manifold ! Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-335360 Share on other sites More sharing options...
steeler Posted June 7, 2016 Author Share Posted June 7, 2016 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. Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-335766 Share on other sites More sharing options...
TRH Posted June 15, 2016 Share Posted June 15, 2016 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 Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-336678 Share on other sites More sharing options...
steeler Posted June 27, 2016 Author Share Posted June 27, 2016 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. Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-337669 Share on other sites More sharing options...
turckster Posted June 27, 2016 Share Posted June 27, 2016 Good catch on that. It's little things like that that will have you pulling hair. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-337688 Share on other sites More sharing options...
steeler Posted June 27, 2016 Author Share Posted June 27, 2016 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! Quote Link to comment https://www.bigmacktrucks.com/topic/45495-us07-mp7-excessive-black-smoke/#findComment-337690 Share on other sites More sharing options...
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