sask3500 Posted April 3, 2019 Share Posted April 3, 2019 I’m working on a 1996 E7 427, no flash codes. Distinct miss at idle, heavy smoke on startup, gets better once leveled out and running. Has tarry schmoo coming out rear half of manifold, and all other exhaust joints after that. I’m looking for advice on how to nail down which injectors to change. I’m soaking stuff in wd40 then plan on pulling the manifold off to see what I can see. No real consistent results from cracking fuel lines at the pump. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
fjh Posted April 3, 2019 Share Posted April 3, 2019 (edited) Possibly a broken injector tip ore a bad valve bent push rod I would pull the back valve cover first what colour is the smoke? Edited April 3, 2019 by fjh Quote Link to comment Share on other sites More sharing options...
sask3500 Posted April 4, 2019 Author Share Posted April 4, 2019 Heavy grey/white starting up, light white idling. Heavy again accelerating. I’ll check the valve train, I’ve decided to get all the injectors pop and spray tested anyhow. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Ezrider Posted April 4, 2019 Share Posted April 4, 2019 i would guess a nozzle tip problem. wont throw a code for that as there not electrical and the unit pumps cant know the difference. you could pull the ex manifold off and see if you can narrow it down to smoke out of one port. Quote Link to comment Share on other sites More sharing options...
j hancock Posted April 4, 2019 Share Posted April 4, 2019 Maybe try using a laser infrared thermometer on the exhaust manifold ports. A cooler temp on a port could indicate fuel wash. 2 Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
Mack Technician Posted April 4, 2019 Share Posted April 4, 2019 Pulling the manifold will show a wet hole. Make sure you run it cold for two minutes before pulling the manifold. Typically......check the timing to make sure you didn’t have a gear slip then buy new tips for all the injectors. Assuming you got a good service life from your injectors, they are essentially spark plugs...when it comes time for one to be replaced the others are usually not far behind. If your cold region consider Fred’s warning about bent tubes. It was popular on those to bend tubes, especially if you had a bad injector applying diesel-pus-super-glue to the valve stem. After a cold night sitting that crud glued the stems solid and bent the tube at start-up. Did a bunch of them from the same issue even with good injectors but driver idled too long, cool, before shutting off for cold night storage. Quote Link to comment Share on other sites More sharing options...
sask3500 Posted April 4, 2019 Author Share Posted April 4, 2019 5 ports were wet. Number 2 exhaust not stroking, pushrod dropped out of sight and intake rod is bent. I’m going to pull the pan and the back valve cover and have a peek up there I guess. Anyone know a good Mack wrecker and engine compatibility across years and models? Any hp is fine. Mechanical motors are fine too. Closer to a drop in swap the better. Thanks for the help so far folks. Pics for your pleasure:Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
sask3500 Posted April 4, 2019 Author Share Posted April 4, 2019 Well it’s better than I expected. Cam seems fine, can’t get at the followers. Any tricks on loosening a sticky valve? With the hours on it we’ll likely put 2 new push rods in and see how it goes. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted April 4, 2019 Share Posted April 4, 2019 (edited) Youch!....get a tar bucket maw, we’re reseal’in the driveway! Soak it with brake clean a few rounds, air bath, spray it with WD40, soak, and brass hammer(piston close to TDC). Edited April 5, 2019 by Mack Technician Quote Link to comment Share on other sites More sharing options...
fjh Posted April 6, 2019 Share Posted April 6, 2019 (edited) Youch!....get a tar bucket maw, we’re reseal’in the driveway! Yup Agree ! OOP"S IMPORTANT info --> ( piston close to TDC) Make sure you don't knock the keepers out beating on those valves! Edited April 6, 2019 by fjh Quote Link to comment Share on other sites More sharing options...
fjh Posted April 7, 2019 Share Posted April 7, 2019 The good thing here is the new style followers Did not face crack like the old days if this had happened to an E6 the cam follower and cam would likley be done for buy now .You are sitting pretty good here for a repetitively cheap repair! Good luck with it bro! Quote Link to comment Share on other sites More sharing options...
JoeH Posted April 7, 2019 Share Posted April 7, 2019 (edited) 4 hours ago, fjh said: The good thing here is the new style followers Did not face crack like the old days if this had happened to an E6 the cam follower and cam would likley be done for buy now .You are sitting pretty good here for a repetitively cheap repair! Good luck with it bro! We used the cam from our spare engine last year for that exact thing. Carbide face cracks, wipes the lobe right off the camshaft. Mack doesn't make the endt676 cam any more. Any time an engine does a hiccup I generally pull valve covers and oil pan. Valve covers will show you if you're having top end issues, oil pan shows you everything else, plus the pieces that may have dropped down. Edited April 7, 2019 by JoeH Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted April 7, 2019 Share Posted April 7, 2019 26 minutes ago, JoeH said: We used the cam from our spare engine last year for that exact thing. Carbide face cracks, wipes the lobe right off the camshaft. Mack doesn't make the endt676 cam any more. Any time an engine does a hiccup I generally pull valve covers and oil pan. Valve covers will show you if you're having top end issues, oil pan shows you everything else, plus the pieces that may have dropped down. FYI- if you ever get in an availability “pickle” Berry Cam Service out of Minnesota would likely fix that camshaft core. I had him build a cam for my rod decade back. He is tooled for Mack right up till E-Tech I believe. 1 Quote Link to comment Share on other sites More sharing options...
JoeH Posted April 7, 2019 Share Posted April 7, 2019 Good to know for the future! I think I stuck that damaged core back in the spare motor to keep the lifters from falling into the oil pan! Now the truck we put the good cam in is retired, (split frame) so it's our spare motor lol! Quote Link to comment Share on other sites More sharing options...
sask3500 Posted April 20, 2019 Author Share Posted April 20, 2019 Update in case anyone needs or wants the info. Ended up pulling the front head to unstick number 2 exhaust valves, replaced 2 bent and one broken pushrod. Oil filters had aug 2011 marked on them, air filter housing packed with chaff and dust. Not just filter, entire housing. Packed. Fuel filters rusted on, took a 3’ chain wrench to pull them off. Re assembled, set valves, new oil and all filters, new fuel return line from head, primed and started nice. Still a bit of a miss but likely an injector. Much better than before. The 3 cylinders I saw were badly glazed, the top end was pretty gooey, a nice sludge in the pan too. I cleaned what I could get to. I’m worried about the turbo long term. Carbon filled a lot of the hot side turbine clearance, it really should have been torn down and rebuilt too.Neat little motor though, nice to work on, tidy valve train, stout and well thought out bottom end, I like the main bearing cap design-and you can’t really go wrong with an inline Bosch pump. I don’t think I’d turn a good one down if I had to go truckin’. Sent from my iPhone using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
sask3500 Posted April 20, 2019 Author Share Posted April 20, 2019 And thanks for your input folks. I appreciate it. Sent from my iPhone using Tapatalk 1 1 Quote Link to comment Share on other sites More sharing options...
terry Posted April 20, 2019 Share Posted April 20, 2019 Thanks for the update, always nice to hear how things turn out. There are some real knowledgeable people here. terry Quote Link to comment Share on other sites More sharing options...
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