I have no idea what the auxiliary valve is. From what I have read, it seems
to shut off air flow when the engine gets hot, and it somehow controls idle
speed. I removed it and tested it in boiling water and there was no
movement of the valve inside. My engine hasn’t been running very well and
it gets worse as time goes by. It seems like a vacuum leak because the
engine lacks a considerable amount of power, and the left-hand exhaust is
really weak. And the engine usually dies after a short while… AND… if I
give it some gas, it dies down before it revvs up.
So will a faulty auxiliary valve cause such problems?
'78 xj-s
Jeff,
as you say, the auxiliary air valve (AAV) should be open when the engine is
cold,
and gradually close as it warms up. When closed, the idle speed is set by the
adjustment screw. Several list members have successfully repaired them, and
the
procedure is in the archives. I thought I had downloaded a copy of an
especially
good post on this, but I can’t find it. You might also find a procedure for
this
in Kirby’s book.
Your problems seem to point mostly to a lack of fuel. How many miles do you
have on your fuel filter?
I have no idea what the auxiliary valve is. From what I have read, it seems
to shut off air flow when the engine gets hot, and it somehow controls idle
speed. I removed it and tested it in boiling water and there was no
movement of the valve inside. My engine hasn’t been running very well and
it gets worse as time goes by. It seems like a vacuum leak because the
engine lacks a considerable amount of power, and the left-hand exhaust is
really weak. And the engine usually dies after a short while… AND… if I
give it some gas, it dies down before it revvs up.
So will a faulty auxiliary valve cause such problems?
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
3
I have no idea what the auxiliary valve is. From what I have read, it seems
to shut off air flow when the engine gets hot, and it somehow controls idle
speed. I removed it and tested it in boiling water and there was no
movement of the valve inside. My engine hasn’t been running very well and
it gets worse as time goes by. It seems like a vacuum leak because the
engine lacks a considerable amount of power, and the left-hand exhaust is
really weak. And the engine usually dies after a short while… AND… if I
give it some gas, it dies down before it revvs up.
So will a faulty auxiliary valve cause such problems?
Nope. A faulty aux valve will either result in a high idle when warm
or a low idle and stalling when cold.
– Kirbert | Palm’s Postulate:
| If anything is to be accomplished,
| some rules must be broken.
| – Kirby Palm, 1979From: “Jeff Peirson” jpeirson@HotPOP.com
engine lacks a considerable amount of power, and the left-hand exhaust is
really weak.
Sounds like the throttle butterflies need adjusting, or a blocked exhaust.
And the engine usually dies after a short while… AND… if I
give it some gas, it dies down before it revvs up.
That sounds like your throttle switch is broken or disconnected. If you
move the throttle open with the ignition on, but the engine not running,
you should hear the injectors click several times, if they do, then the
switch is OK.
I have no idea what the auxiliary valve is. From what I have
read, it seems
to shut off air flow when the engine gets hot, and it somehow
controls idle
speed.
All correct.
I removed it and tested it in boiling water and there was no
movement of the valve inside.
The technical term is knackered. New valve time (not cheap).
My engine hasn’t been running
very well and
it gets worse as time goes by. It seems like a vacuum leak
because the
engine lacks a considerable amount of power, and the
left-hand exhaust is
really weak. And the engine usually dies after a short
while… AND… if I
give it some gas, it dies down before it revvs up.
So will a faulty auxiliary valve cause such problems?
No. The most a faulty valve will do is give you a high idle speed. You
have got some other gremlin in there somewhere. I have no experience of
catalysed V12s, but if your lh catalyst was plugged, that would explain
why there is not much coming out of the lh exhaust. Another possibility
is a fault in the wiring to the injectors on the lh bank. They are
wired as two sets of three, but the wires common up at the ECU in the
trunk. If the wiring to a group of three was down, that would give you
a pulsing exhaust on that side. If all six were down (it could be
either wiring, or the ECU), the engine would still run, but very
roughly, and be totally gutless.