OJ Avery Posted December 15, 2017 Share Posted December 15, 2017 I have an 08 mp7 no start. inactive codes mid 128 sid230 fmi 5. followed diagnostics out to a bad vecu. Will this cause a no start? Has been a hard start for a couple days, now a no start. Also has a #4 injector code for mech failure. I've had the injector code before but it still runs, poorly but still runs. I have been told about the air/fuel valve for the 7th injector back feeds air into the fuel system and for whatever reason will set the #4 injector fault. Thoughts? Quote Link to comment Share on other sites More sharing options...
OJ Avery Posted December 19, 2017 Author Share Posted December 19, 2017 Update... I changed the filter head, one of the check balls for the filter (primary ) was stuck open. I thought this solved it...nope, now its a hard start. I replaced the fuel pressure regulator on the return side of the head as well as the valve/ banjo fitting on the filter head on the return to tank line. still hard start. Ive run it hard outside and it runs great but 30 seconds after shut down it has to crank a long time to catch. Help please!! Quote Link to comment Share on other sites More sharing options...
fjh Posted December 19, 2017 Share Posted December 19, 2017 Injector cups!!!! Quote Link to comment Share on other sites More sharing options...
OJ Avery Posted December 19, 2017 Author Share Posted December 19, 2017 thanks fjh, I was reading the mp8 posts on no start / hard start and came to the same conclusion. I'll do an air in fuel test tomorrow to confirm. I really thought I had solved it tho finding the one check ball stuck open on the secondary filter,I guess that was a problem too. Thanks for the response!! Quote Link to comment Share on other sites More sharing options...
OJ Avery Posted December 19, 2017 Author Share Posted December 19, 2017 so let me give you a little more detail to see if you still believe injectors. I got it all together from replacing filter housing. started good, ran great down the road. turbo had 38# of boost, pulled hills good. Now what I have experienced in the past (I've only been working on these mp7's for 5 years ) is the turbo wont build any more than 30# of boost with bad injectors. If they are bad, why would it still pull this amount of boost?? Quote Link to comment Share on other sites More sharing options...
Mackpro Posted December 20, 2017 Share Posted December 20, 2017 (edited) You get any low fuel pressure codes? The engine ecm cooler plate seems to get clogged a lot on the older MP engines . Blow the lines out. Has the injector code come back? I had a MP 8 a few weeks ago throw a injector code and it was a bad camshaft . Missed like crazy though Edited December 20, 2017 by Mackpro Quote Link to comment Share on other sites More sharing options...
OJ Avery Posted December 20, 2017 Author Share Posted December 20, 2017 I didn't have any low pressure codes, I don't think I have ever had one. I already checked/ blew out the cooler lines, I have found them packed full of crap before as well a few times but this one was clean. I believe each time they were using bio. I work for NYS DOT and we have a lot of Macks from 08 to 15 so I have seen a lot of the common stuff. This 08 has never had injectors which is a little odd. I just thought for sure I fixed it when I found the stuck check ball in the fuel filter housing. well I'm off to order my 6 pack and get this done, thanks for your input, I appreciate it. The bad camshaft you had, was it just worn? or broke? Our trucks don't have a lot of miles but they get a lot of hours so we do go through a lot of injectors. Quote Link to comment Share on other sites More sharing options...
OJ Avery Posted December 20, 2017 Author Share Posted December 20, 2017 busted off 3 tips of the injector cups...ugh!! I've never done that before. I've probably changed out 10-12 sets. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted December 20, 2017 Share Posted December 20, 2017 (edited) We have had to weld a nut on the top of injectors befor and slide hammer them out when stuck in the cup. Mack has a really quick cup removal tool now, works great. On the cam issue, it was a injector roller bad and ate up cam. Thoses were 2010 Tyson MP8's and a few 2013's as well. Edited December 20, 2017 by Mackpro Quote Link to comment Share on other sites More sharing options...
OJ Avery Posted December 21, 2017 Author Share Posted December 21, 2017 I tried the mack extractor but its such a fine thread it pulled right through. I ended up using a ford spark plug removal tool. I adapted to make work. did a great job. I have never seen such a carboned cup!! #3 & #4 were unbeliveable Quote Link to comment Share on other sites More sharing options...
OJ Avery Posted December 22, 2017 Author Share Posted December 22, 2017 Injectors solved the problem Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.