wgharper

How much boost should register on the gauge at idle?

My reason for asking - I had been seeing 0.0 boost until up in the 2000-2500 RPM range on the car, then it would climb to 0.7 progressively. I did some poking around last night to hunt for oil leaks and do some routine maintenance. I removed the intercooler and airbox, and replaced the fuel filter, cap/rotor, and air filter. While pulling all the stuff off, I also noticed that the tube connecting the turbo to the intercooler was not firmly attached to the turbo outlet. It was seated on top of the pipe, but was not clamped down well.

Anyway, I fixed this, and put everything back together. Now, the boost is reading 0.1 to 0.2 at idle. Car still performs fine, but I haven't pushed it too hard, for fear of doing damage. So, did I fix a problem, or create one?

Geoff

John McM

It should read zero on idle, but the problem is almost certainly with the gauge sender. My car has the same issue. In fact sometimes it reads 0.7 boost on idle. Gauge is next to useless when it works so I'm not fussed about fixing mine.

nathanUK '81 930 G50

There will in fact be a vacuum at idle.

wgharper

So, on the way home from work today, I noticed that with the ignition on, but engine off, the gauge is showing 0.1 or 0.2. Seems to be sending a false signal, per John's comments above.

Since I didn't have this problem before, could it be that I need to clean the contacts for the sensor? Is it one of the ones on the back left (facing rear of car) of the intercooler, or is it the one under the connection to the throttle body?

Youcef

I have no faith at all in the OBC boost gauge, I installed an EBC and rely much more on its reading.