Hey fellow Disco enthusiasts!

My '17 TD6 HSE w/ 130,000 miles has recently developed a stall and dip in the RPM's when driven first thing in the morning from cold start. I have to make a conscious effort to switch quickly from brake to throttle at the first few stoplights to keep the vehicle from stalling out. No CEL, no codes, nothing, vehicle still runs like a dream. Once the vehicle is up to temp there are no issues with the RPM dip/stalling and my fuel economy has been in the 22-26 mpg range. I drive this truck on the highway daily with a 30-40 minute commute one way, and we always have it out on the highway as it is our weekend road trip car. Any recommendations on where to go from here? Doesn't seem like a vacuum leak, possible EGR or DPF clog/malfunction?

Many thanks as always!

 

Try cleaning the MAP sensor if not done recently

 

I will clean that again tonight, did that with my most recent oil change. Thanks for the recommendation!

 

Re-cleaned the MAP Sensor and read codes, this was the only one of interest, any thoughts?“ECM (Engine Control Module) 1 problem exist

Confirmed

1.P2BAE-00 NOx Exceedance - NOx Control”

 

Would try cleaning the DEF injector, but I don't think that a clogged injector would impact driveability

 

Agreed. Will report back if I still have a stall on the way into work in the morning.

 

Any idea on what the MAP Sensor readout should be if it’s functioning properly? Mine was at 1.03V at idle. There has been a slight sweet smell, not coolant as I’ve been checking that like a crazy person. Is that potentially indicative of clogged DEF injector or filter? There was what looked like a lot of soot on the MAP Sensor when I cleaned it tonight. Attaching a photo of the inside as well.

 

Engine off and at idle the MAP psi should be roughly +/-14.7 psi, which is atmospheric pressure at sea level (no boost). At higher elevation it'll be lower. If your reading is in that ballpark I'd move on from the MAP. Mine has been "clogged" to the point of noticable driveability changes until after cleaning. I wouldn't suspect the DPF being clogged there would be other codes associated with inefficiency etc. Cold idle you'll smell an odd smell especially long idle which is normal.

 

Thanks! Mine was reading at 14.1. Great information!

 

No shudder this morning, but hit all of the lights before merging onto the highway so no real opportunity to stop. Can you clean the throttle body on these? Need to pull the hose off, but wondering if my TB and flap are covered in soot resulting in some of the stalling.