5-cylinder HPT vacuum diagram B5234T

Post by **matthew1** » 11 Aug 2026, 08:46

We've got a bunch, but this is a different take, and beautiful. Wastegate, FPR, EGR, boost gauge, purge valve, TCV with Red/Yellow/Blue, and more. This is mid-1990s 850 Turbo 2.3 liter.

Sent in by anonymous user Dee Eff.

Post by **BlackBart** » 11 Aug 2026, 10:07

That's good. Now is that a Euro 2.3, or is that the same engine as the '94 T-5? From the diagram, that looks identical to my system. I guess there would be no reason to change all that for variations - it would be changes in pistons, valve timing, boost control, etc.

EDIT: It says right on there, 1995.

Post by **BlackBart** » 11 Aug 2026, 10:12

Interesting in that I've always had a code for "EGR flow too low." I've removed it, tested it, cleaned it, and now they're no longer available new. Always ran great, plenty of power, no issues, just this code. I've replaced all the colored vac lines with silicone.

BUT...I don't think I've ever messed with the EGR vacuum regulator, which is the bit on the upper radiator shroud I think. Hmm.

Post by **Olegs855R** » 11 Aug 2026, 23:05

Yes, upper radiator shroud. Has 2 ports marked white and yellow.
I drew this a while back as I have a rotten memory and I’d need to try to decipher the hood sticker. It hangs prominently on the wall . It’s around 2 feet square.

Post by **abscate** » 11 Aug 2026, 23:22

If you have an early 1999 like mine, it’s likely the vacuum diagram is wrong, Volvo used up their supply of 1998 stickers on our cars. I think I documented this in Elizabeth msintenamce thread