Volvo Owners Club Forum - View Single Post - D5 (D5244T to 2005) - Low Speed Loss of Boost. Takes along time to buildup.

cheshired5 · May 31st, 2021, 15:45

Both your before and after cleaning MAF figures are credible depending on EGR position.
If you leave it idling long enough, it will jump back up to 50 kg/h which is normal behaviour and suggests that the EGR is working correctly.
See my earlier post #9

Based on everything I've read of your situation, I would now concentrate on the vacuum pump and if you can't get a stable non flickering full vacuum at idle (around 29 in/Hg) when testing directly on the vacuum pump, change the vacuum pump and I'm confident that the boost issue will resolve itself.

May 31st, 2021, 15:45	#13
cheshired5 Premier Member Last Online: Dec 26th, 2021 13:42 Join Date: Dec 2013 Location: Crewe	Both your before and after cleaning MAF figures are credible depending on EGR position. If you leave it idling long enough, it will jump back up to 50 kg/h which is normal behaviour and suggests that the EGR is working correctly. See my earlier post #9 Based on everything I've read of your situation, I would now concentrate on the vacuum pump and if you can't get a stable non flickering full vacuum at idle (around 29 in/Hg) when testing directly on the vacuum pump, change the vacuum pump and I'm confident that the boost issue will resolve itself. __________________ 2002 S60 SE D5 Manual 209000 miles