Jump to content

2012 MP8 EGR Mass air flow


Recommended Posts

I keep getting code for EGR mass air flow rate valid but below normal

Truck has new turbo EGR valve cooler and mass air flow sensor 

Pressure tested intake cant find the problem

Mack has an updated venture tube and sensor but its on back order

Any help?

Link to comment
Share on other sites

I think this is the 4th or 5th or maybe 6th revision of the EGR differential pressure sensor and Venturi pipe.  And yes lots of parts are on back order right now. We waited 3 weeks for the newest EGR diff sensor and pipe kit for a mp7  MRU . I'm waiting on a secondary fuel filter for my buddy's new GU with the common rail engine. You can get in in a kit but alone their back ordered from hell. The common rail engine takes a different secondary fuel filter than the older MP engines. 

Link to comment
Share on other sites

Have you checked the egr diff. psi sensor ports on the venturi? The fault is for low or little flow so one or both ports could be plugged, which is common. If one or both are plugged you might be able to clean them out but eventually the venturi will have to be replaced. 

Link to comment
Share on other sites

Being the code is for low EGR  flow. Either the EGR diff sensor is not reading correctly or the cooler is plugged. In the first bulletin it talks about the cooler being plugged and replacing the cooler and updating  the ECM programming to prevent the cooler from clogging again. We always try the updated EGR diff setup and a engine ECM update. Then see if it solves  issue. If code returns the replace EGR cooler, this is last resort as the turbo bolts usually break off and is never fun. 

Link to comment
Share on other sites

Well about them turbo bolts.

When this all started with this code I cleaned the tube replace the sensor cleared the code and went for a road test.

Empty ran great no engine light so I went to the quarry half way back the turbo locked up great 73,280 no turbo.

So any way when I had the turbo off with the now broken bolts I changed the cooler and valve since they were never changed.

So looks like I will be waiting for my new venturi tube

Link to comment
Share on other sites

  • 1 month later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...