2013 XC 90 D5 uneven throttle response, easy stalling

arebee

Hi All,

Had a DPF problem with my other half's D5. Tried twice with VIDA to do a soot burn, without success. Then added Penrite DPF cleaner aerosol via the temperature port, and this seemed to make the problem worse, causing the engine to stall very easily. I surmise that this was due to loosening up some soot, and then inadvertently compacting it further down into the DPF. No problem… I then removed the DPF and added some water to the outlet end of it, gave it a solid shake and a whole heap of black sooty crap exited the front entrance of the DPF. I then redid the Penrite treatment from the exit end, and managed to clean out more crap. The water flow through the DPF was now quite good, water also exited clean.

I then reassembled the exhaust, and engine started OK, I cleared the codes, and none have reappeared.

The problem is that the engine response is erratic when one presses the accelerator, and I have also noted what I think is a fuel smell around the engine bay.

What have I failed to do correctly here? I am sure that I missed something.

As always your collective and individual sagely advice is keenly appreciated.

arebee

I'm starting to think that it may be a dirty throttle body, since there are no codes, and the stupid level of back pressure encountered with the mostly blocked DPF could have clagged the throttle body by somehow forcing crap back through the system?

Ex850R

TB is before the DPF but if thats a swirl lap motor it may be them , these motors are not great when going bad.

Also yes , the crud could be in the ystem now , none of those supposed cleaners do anything but driain your wallet , it all needs to be pulled apart and those in the know need to do it and see what else is wrong so do that…

Just spent $2500 on the S80D5 incl tappets and lifters . swirl flaps, soot and gunk cleaned by a decarbonsiing place for hoses , cam cover and a tube that was lined with 6mm of crud ($200 cleaning cost) An injector . Leaking swirl flap seals and new arm for the new flap kit , seals etc etc , really not worth it and if more injectors go this car is gonna be scrapped , im over the stupid thing. 160,000KLM and driven hard all the time with good fuel from same pump same servo. Petrol motors are cheaper to run and own!

arebee

Well, after a bit of mucking around, (and having also cleaned out the throttle body, which was somewhat mucky), I have finally discovered the cause of all my current woes…

Its a seal, Volvo part number 30778628, I think that it is called an upper inlet tube seal, located at the rear of the engine, and up a bit. Here is a photo of the offender (the rubber bit, not me…..)

Image description

I monitored a whole bunch of stuff via VIDA, and noticed that the ECM Boost pressure versus the ECM desired boost pressure were quite at odds with one another, leading me to seek out the culprit on the turbo pressure side of things..

Just for the record, the pressure sensor (which I think is actually differential pressure) for the DPF reads around 13 hPa at idle, and cranks up to a max around 60 ish at higher rpm. Will remeasure once we get 'Eric' all back together again, but I think that these values look OK to me.

arebee

Replacement seals were obtained and fitted today. Somewhat tricky to fit, and tightening the hose type clamp (jubilee clamp) is essentially impossible on the upper joint ( I could not get access to it, so instead I tightened it to a such a degree that I had to use significant force, hand pressure only) to press the upper seal 30778628 with tubing into position. The lower one was also awkward, in that it was quite tight. I ended up using a thin bit of oil to lube the joint and then I also ended up making up a bit of softwood to go between the lower rear part (which had a flat edge on it) and the cross member, and then used a thin flat piece of softwood on the curved part at the other end to gently lever the two halves together. It ended up all OK, and a driving test demonstrated that all is running very well, the anticipated / actual turbo pressure in reasonable agreement. The DPF pressure gauge also reads 9 hPa at idle, and approx 60 hPa at 2000rpm, which I think is reasonable. When I had the blocked DPF, I recall it was well over 600 or 650 hPa, before it all went very pear shaped.

Finally, I can get back to working on my Amazons……