Turbo boost.. Do I have a wastegate problem?

[RJ Gilliam]

My 86 930 is acting wierd. I do not know if I am just paying more attention or I have a problem brewing. When I stand on it at about 2400 in 1st gear the boost goes to .6 no higher, then when I shift into 2nd it goes to .7 and slowly down to .6 (gets there before 5500 RPM)

I do not know if this is a problem with the wastegate dumping to early or this is what is suppose to happen. The guage is a VDO full circle so I dont think I am just misreading it.

Advice, suggestions, comments...

[logician]

Hi RJ,

> My 86 930 is acting wierd. I do not know if I
> am just paying more attention or I have a
> problem brewing. When I stand on it at about
> 2400 in 1st gear the boost goes to .6 no higher,
> then when I shift into 2nd it goes to .7 and
> slowly down to .6 (gets there before 5500 RPM)
>
> I do not know if this is a problem with the
> wastegate dumping to early or this is what is
> suppose to happen. The guage is a VDO full
> circle so I dont think I am just misreading it.

You can hear when the waste gate opens up. I can hear mine when I roll down the driver's window. It makes a loud sort of hissing sound when it opens. It is especially evident if you are driving next to a wall on the driver's side.

I can't say exactly what the boost gauge should read, as mine has always been a little flakey so it is questionable. Also, I don't know if I have a 1.0 boost spring. One thing that I have noticed, and have also heard from other 930 drivers, is that the amount of maximum boost seems to be different in different gears and speeds.

Actually, for the past few weeks, my stock boost gauge has been reading high -- gets pinned at 1.0. It used to get pinned only in second, but in first it would max out at .8. Now it gets pinned in first as well. I'm concerned that perhaps my waste gate is not openning when it should. Could be a gauge problem too, but how would I distinguish the two?

-Juan

[beepbeep]

If boost too low -> WG valve is cracked/leaking or impeler is worn

If boost too high -> pressure line to WG is leaking or WG-membrane is leaking