I was test driving a '96 turbo, it ran good, really good. At a red light, about 1000 RPM it was bouncing between 0 and .2 Bar, avg. .1 bar, and it goes right to .8 as soon you hit it. Is this good or bad? The car had a big after market intercooler but otherwise appeared stock. Owner said he has no records, the speedo had marks from being pryed out of the dash, but overall it looked nice. Showing 15k miles, looks more like 30-40k but I can't tell. Willing to sell it in the low 60's. Polar silver with classic grey. Not sure what to do about if anything. The boost has me curious though.

 

It is a common problem that the digital boost gauge shows .2 or .3 bar at idle. Nothing to worry about.

 

It's a little odd that the owner didn't have any records, no oil change or tire receipts, belts, and so on...

 

One doesn't normally put a big intercooler on an otherwise stock TT. I would guess that either it has more mods, or the other stuff has been removed. Look carefully.

 

PPI!!!!! Something does not sound right there overall. The boost gauge thing is a calculated number and does not necessarily correspond 100% to reality...

 

If the boost gauge number is a computer calculated output, then it makes sense to assume that the input or calculation is corrupt or errenous. What inputs does it take to calculate boost pressure? Is it just a pressure sensor or does it take into consideration values from the MAF meter? It could be a vacuum leak or something that is triggering these wierd numbers.

I also have the 0.1-0.2bar showing at idle *after* the trackday and it seems almost everyone gets the problem after spirited driving. The two seem related. Perhaps a vacuum hose has popped off which is now providing the computer with bizarre numbers and it is calculating wrong?

Does the OBD2 light the CEL if there is a vacuum leak? Is it that sensitive?

 

FC racer:
I've had that problem with the digital boost gauge showing boost pressure at idle. Dealer replaced the boost sensor and its been good since.

AFAIK, the boost sensor of the digital boost gauge is not being used by the ECU whatsoever. ECU is using the mass air calculation for fuel metering