[urq] Cold start, thermo time switch, Frequency valve

[j.koenig]

A couple of thoughts, for what they're worth...
(I'm relying on memory rather than recent experience.)

If memory serves, the frequency valve should be operating all the time.  The duty cycle 
varies when running closed-loop, but defaults to fixed values for open-loop, WOT, etc. 
Your description of how it starts/runs suggests that you can achieve a decent mixture 
adjustment under closed-loop conditions, but that for some reason the default values are 
giving you a very lean condition.

Is something causing it to want to run rich, so that your closed-loop mixture adjustment 
leaves you hopelessly lean for open-loop?  What happens of you run it warm, closed-loop, 
mixture adjusted, then disconnect the oxygen sensor?  If everything's working and adjusted 
properly (fully warm, etc.), it should run just about as well open-loop (w/default duty 
cycle -- 50% maybe?) as closed-loop (hovering +/- around 50% w/O2 control).

Otherwise, I think you might have an issue with whatever powers the frequency valve 
(and/or determines its fixed duty cycle) when it's not running closed-loop.

And, of course, what happened that might be different as a result of whatever was 
disconnected, disassembled, etc., for the paint job?

Good luck!
John

----- Original Message ----- 
From: "Gary Brown" <gmbchef at sbcglobal.net>
To: <urq at audifans.com>
Sent: Sunday, March 16, 2008 2:06 PM
Subject: [urq] Cold start, thermo time switch, Frequency valve


Guys -

 This is driving me crazy.

My cold start valve still isn't firing even though all of the wiring and
physical tests of all parts found all systems go.

Also, it takes forever for the frequency valve to buzz, although sometimes
it will buzz during warm up when the fan kicks on, then stop as fan turns
off.

I had all of this sorted out before the paint job. The car would fire right
up and be driveable no matter how cold.

Now, after 20 minutes or more, the FV starts to buzz. I'll set the duty
cycle, car will run great!

Then, after a brief cool down, no more FV buzz, then over night, car will
not start with out a few cranks of the air plate screw.

No vacuum leaks at all either.

Am I missing something simple?

Thanks

Gary

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