Re: Turbo Frequency Valve Check

[mallick@orion.crd.ge.com (John Mallick)]

Mike wrote...

Got a call from Ned last nite. He knows that I am chasing a low boost problem 
on a 91 200q and wanted to share some info. Thought I would pass it on. Two 
other people had recently had the same problem and fixed it by replacing the 
turbo frequency valve. According to the info one guy gave to Ned, there should 
be 25 - 34 ohms across the terminals - this guy was seeing about 300 ohms and 
was only getting 1.3 bar boost. My understanding of how the frequency valve 
works is that it pulses boost to the bottom of the wastegate, causing the WG 
to open - obviously if you pulse too often, the WG will be open too much and 
boost will not build.

mike miller
91 200q
...

30 ohms is about right.  Also, if you disconnect the connector and
apply 12V to the frequency valve, you should hear it click.
Interesting...if the resistance is too high, you would think that the
valve wouldn't open and you would go into overboost.  BTW, I think
that the ECU can sense a bad connection at the frequency valve and
report it in one of the codes.

FYI, I'm still chasing my stuttering problem at high boost (>1.5 bar).
Gonna install a mechanical boost guage to see if I am hitting an
overboost limit.  Maybe my wastegate is stuck closed?

John Mallick
'91 200q