Setting TR Fuel Mixture

Hi JRV:
Thanks for the input.
When you adjust the mixture, reading exhaust gas precat, do you disconnect the frequency valve or is the mixture set trying to get the correct numbers while keeping the DC near 50%? The frequency valve seems to be a "fixer" creating an ideal final mixture as long as there is a close mechanical adjustment. It seems a DC setting of 50% would allow the system to fluctuate the maximum amount either way.
Thanks,
Mark

hi Mark & Carl,

never unplug Frequency valve...only O2 sensor when appropriate.

Yes there are setting and testing procedures that do vary. Testing -(1) everything hooked up/warmed up...setting- (2) O2 Sensor Disconnected, make corrections at FD as necc. allow to stabilize...checking(3) replug O2...recheck...it is also possible that the AIR may need corrections and it is neccesary to check the throttle position and throttle position sensor as well as the air bypass screw setting.

To check duty cycle however the O2 sensor must be connected and in closed-loop.

JRV perhaps this is a stupid question but -

When checking the DC of the lambda/frequency valve, should one connect "in series" with the two-prong lead (i.e. one wire of dwell meter to one, other side to other) or only to one side then ground? If not, how is this properly done?

Thanks,
Carl

If you wish to check the mixture by the o2 sensor voltage, leave the o2 connected,but measure by connecting the +ve of voltmeter to the o2 connection and the -ve to ground. A good system will show a slight fluctuation around 0.8v.

Hi Mr. Stewart,

Actually using my digital VOM when doing this found fluctuation three rapid digits then "overload"; using my analog meter got needle swinging from (roughly) 0-1.0v.

O-2 sensor disconnected reads 0.886mV. Just posted another thread on reading DC directly? Do you know where/how to measure?

Thanks for your help,

Carl