What is causing this! My friend is going crazy!
My friend has a 2007 Volvo 670 with a D12 465hp engine. He has a big drop in turbo pressure at higher altitude and high ambient temerature. At lower elevation he has up to 36lb boost down to 1200rpm but when he gets to say, 6000 feet with high summer temperature he is down to 15lb!
He has replaced a ton of stuff including the ECU which has a barometric sensor in it.
Any ideas? Please!
Is this a worthwhile discussion?