With the latest discussion regarding the benefits, moral and otherwise, of a
properly operating EGR valve, I thought I would interject a question I have
posted before and never received a satisfactory answer: What is the purpose of
the vacuum hose connection off the EGR valve which leads to what appears to be
a small connector or switch associated with the choke linkage at the base
of the rear carb on a '74 TR6 engine? This flows through one port of a
Y connector to the top of the EGR valve; the other port of the Y leads to a
fuel trap then to a connection at the top of the same carb.
My guess is that the lower connection is meant to disable the vacuum draw from
the upper connection to the EGR valve when the choke is pulled. Or am I
mistaken and this is how the throttle linkage reduces the effect of the
EGR valve at full throttle (and it just happens to be next to the choke
mechanism)?
I am asking because in my drawn-out attempt to pass CA smog, during the last
pre-test I took (and failed) the mechanic said was EGR valve was not
operating. The vacuum connection to the choke (and/or throttle) mechanism
at the time was not secure, having been faultily replaced by a previous
smog mechanic. I am hoping that this was the cause of my problem and that
the valve itself if OK.
BTW, how does one tell if one's EGR valve is working?
Thank you in advance for any advice, Richard
|