6.0 diesel 83,000 miles. I can't for the life of me figure this out.

My CEL is always on and my Edge gauge says it's lower than expected Mass air flow.

I've changed the filter, cleaned the MAF with special cleaner and then replaced with new. I've replaced the EGR valve.


If I clear the codes and run it I don't get a CEL until I turn it off. But the next time I start it, there it is again. My Edge reads 0.0-0.3 MAF while running but I have no idea what that means. One end of my cleaner box is slightly warped but I can't feel any noticeable leakage.

Everything runs fine but I would like to regain the ability to have that idiot light available to tell me if I have a new problem.


Has anyone been able to solve a similar issue?

 

Moved to 6.0L PSD engine forum.

Good luck!

 

Since you have replaced the EGR valve and the MAF sensor, we assume they are good (what brand MAF sensor did you install?).

Remaining possibilities:
Air leak before or after sensor
Mass Air Flow Sensor harness is open or shorted
Mass Air Flow Sensor circuit poor electrical connection
corrupted tune

check MAF wiring: connectors and harness for chafing, bent pins, burnt pins, solid connection (including the PCM connector)

Have you checked the entire length of the air intake and the charge air system for leaks?

What does your filter minder indicate? Check its wiring also.

Is the truck tuned? If so, which tune are you using? If so, put it back to stock and see if code can be permanently cleared.

 

Thank you Mark, for those new leads/ideas.

I have never tuned it. Performance stock is great for my needs, and I am concerned about stressing my original studs

It's a Ford MAF. The harnesses are visibly as new. I will try to test them as I learn how.

The filter minder is an excellent idea. I have noted that the last couple times I removed it, there has been no movement at all when I try to reset with the yellow rubber button.
I think I'm going to try duct taping the box ends to isolate that not being a leak problem. I'm guessing only the suction end of the box is really important?

 

Duct tape is a good idea.

 

Check the EBP sensor connection. If that has shorted the Vref then you will
get some odd stuff on that circuit. Been there, Done that.
The wires at that connector are small and looking with a good light and a
magnifier will help. Be sure to look all around each of the wires for
any damage or chaffed spots.

 

I took it all apart again from the turbo thru the filter. I reverse blew out the filter with the air compressor. (Surprising how much dust came out of a filter only a couple months old). I did not know these things are at least modestly serviceable.

I put it all back together carefully and right now (in the driveway) I am not getting the CEL. I will update when I've had time to put on some miles and on off cycles.

I'm sorry I can't specifically ID the culprit. Maybe a loose connection. Maybe the nozzle end of the filter intake was not fully in the grommet in the front (firewall? partially restricted). and then maybe again its not yet fixed at all. Will update. It seems I probably didn't need the new MAF and EGR....... oh well.

 

It's back.... so it's off to chasing wiring again.

 

Have a look at the EBP (Exhaust Back Pressure) Sensor. it sticks up right in
the area that the filter is in.