fracroy Posted July 1, 2014 Share Posted July 1, 2014 Have a mp8 keeps losing prime runs fine for a while at idle but once u start driving starts missing and dies I'm thinking injector cups or improper installation mech before me replaced 1 injector plz help and thanks Quote Link to comment https://www.bigmacktrucks.com/topic/36211-mp8/ Share on other sites More sharing options...
Mackpro Posted July 1, 2014 Share Posted July 1, 2014 I always vote for cups and or injectors. Here is the new info on inspection of your injectors. Look closely at your sealing surface of the injectors , Use the graphite paste and and new injector hold down bolts. Check for cracked tips on the injector with a magnifing glass. Cracks run up and down of the long tip of the injector that goes into the cup. And some times the whole body of the injector just breaks in half. Of course it could also be the the fuel pressure relief valve in front of the head, the filter fuel stand, the fuel supply pump or just a leaking fuel line on the suction side. Look for fuel dripping from where the supply pump bolts the the power steering pump. Seems like 90+% of the time its cup or injector related in our shop. Conical replacement info.pdf 1 Quote Link to comment https://www.bigmacktrucks.com/topic/36211-mp8/#findComment-251292 Share on other sites More sharing options...
wheeler73 Posted July 2, 2014 Share Posted July 2, 2014 I have also seen loose water in fuel sensors on the primary filter. A lot of people remove them from the bowl before taking the filter off instead of disconnecting them from the harness connector and put them back in the same way. They unscrew themself when that is done. Quote Link to comment https://www.bigmacktrucks.com/topic/36211-mp8/#findComment-251313 Share on other sites More sharing options...
fracroy Posted July 2, 2014 Author Share Posted July 2, 2014 I have replaced the relief valve on the front of the head new fuel pump new filter housing New seals on all bajo bolts the is a small hole by were the fuel pump mounts on the power steering pump and diesel and air bibles come out wat is the purpose of that weep hole Quote Link to comment https://www.bigmacktrucks.com/topic/36211-mp8/#findComment-251388 Share on other sites More sharing options...
fracroy Posted July 2, 2014 Author Share Posted July 2, 2014 Do u know the rocker arm asemmbly torque specs Quote Link to comment https://www.bigmacktrucks.com/topic/36211-mp8/#findComment-251389 Share on other sites More sharing options...
fracroy Posted July 2, 2014 Author Share Posted July 2, 2014 Mack pro thank you for the information u you provide ed Quote Link to comment https://www.bigmacktrucks.com/topic/36211-mp8/#findComment-251390 Share on other sites More sharing options...
fracroy Posted July 2, 2014 Author Share Posted July 2, 2014 Mack pro thank you for the information u you provide ed Quote Link to comment https://www.bigmacktrucks.com/topic/36211-mp8/#findComment-251394 Share on other sites More sharing options...
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