recommission of Subaru 2012 Outback

[steven.mccormack2]

I am troubleshooting a Subaru 2012 Outback 2 litre diesel.  If I do a motorway journey for more than 30 minutes the engine runs rough and is almost at the point it stalls. 

I am looking at the MAF reading which is around 8GS at idle. Is this too high? The vehicle had been off the road for some time and bought by a student who did some repairs on his own. 

I've cleaned the MAF sensor but the overall indication from my Autel 808 Pro is that it sits around 8G/S at Idle. What should it read at idle? AI on Google says it should be around 2 to 2.5 G/S.

I have no DTC codes and the history here is that oil dilution triggered a protective mode on the DPF hence my initial work around getting the DPF cleaned and functional. I cleaned the DPF with Wynns EGF/DPF cleaner and after a few cans, all sorts of horrors came out and I was able to do a DPF forced regen from the Autel (even more horrors came out). That worked great and my differential pressure between DPF in and out is 1. 

I've tried cleaning the throttle body housing on the car but am close to removing it for a deeper clean just to eliminate that!

On a motorway journey it runs rough after about 30 minutes of hard motorway driving. Just to cloud the issue though the chap that owned it before did the brakes himself but hammered them in and I found the inner pads ceased in the brake carrier with slider pins ceased and not behaving well either.

I know there's a lot of info here but would the load applied to the ceased brakes cause the engine to struggle? At 80 MPH on the motorway the brakes would swell up with heat? Bind and cause a load on the engine. IS my MAF reading too high? I've already done the celebrity pipe to the intercooler from the low side/throttle body to intercooler?

[steven.mccormack2]

Just to update I have now removed and cleaned the calipers and brakes. I fitted new pads and cleaned up all the burs and imperfections till they fitted perfectly. Greased them with LiquiMoly ceramic grease and the front pads at least are now functional. Slider pins are great too. I'll do the rear pads tomorrow to complete the brake rebuild.

I'm more interested in the high MAF reading but it maybe a red herring? what MAF reading does anyone else have on a 2012 EE20Z engine in the 2 litre variant? If yours matches mine at around 8 G/S then I'm happy. However if yours is at 2 to 2.5 then I'm looking at a faulty MAF or a vacuum leak?

I'm a home mechanic and these are my personal vehicles but the next logical step is a smoke machine to see if there's any vacuum leaks I guess? Any advice will be much appreciated? It's an EE20Z engine and I'm very cautious I don't deliver any engine issues by not addressing the basics?