Inconsistent Boost With A/C Running

[jschaefer7406]

Hello all,

I have a 2000 S70 AWD, totally stock except for the IPD TCV (installed in November). Trouble is, with the A/C engauged, the boost is very sporadic under part throttle. If I accelerate on a level grade, the pressure will go to 5 psi or so, then immediately back to 2, then jump around until I let off. I know the compressor cycling will cause some fluctuation, but is this much normal? Seems better with the A/C off. Any ideas?

Thanks,

Joe

[adamjjohn203]

My car will lose 2 hg of vacuum when the ac cycles and back....back and forth.....I don't use AC I feel it robs boost.

[jschaefer7406]

Hello,

Mine does that as well, and that is true of any car (turbo or N/A) due to the extra load. Mine is strange though (I should take a video of the gauge). It is rock solid when on the vacuum side (A/C or not). It's only under boost that this happens. This almost makes me think it's the TCV, but being new in the fall from IPD, I would assume not. This is the third TCV I have had on this from IPD and this happened with the others also. This has been fine all winter and early spring with the new TCV. Just started this week. Even with the A/C off, lately it's been difficult to maintain a set boost pressure (unless @ full boost). If only @ part boost, it is very touchy and will seem to go to 2 psi for example, then right to 5 if pressed just a hair harder (like theres no middle ground). As said, this happened today even with the A/C off (not as bad though). I don't know if it's maybe the ETS system, but there is no MIL or ETS lamp. It's got me going crazy.

Thanks, and any ideas welcome,

Joe