Thanks again for your accurate descriptions of how things are supposed to
work. I pulled the TCSA solenoid off of the pedal box to clean and examine
it and found it to be working properly. What wasn't working properly was the
"volatile RAM" that I apparently have in place of actual grey matter. I had
switched the vacuum lines around and thereby allowing the manifold to vent
and capturing vacuum in the line to the distributor. Idle is now stable and
set to specs. Thanks again. This list is invaluable.
----- Original Message -----
From: "Paul Hunt" <paul.hunt1@blueyonder.co.uk>
To: "Steve Gorr" <sgorr2@comcast.net>; <mgs@autox.team.net>
Sent: Tuesday, June 08, 2004 11:34 AM
Subject: Re: TCSA & Vacuum advance woes
> As an emissions measure the distributor vacuum takeoff was moved from the
> carb to the inlet manifold. This gives maximum vacuum at idle instead of
no
> vacuum and increases the idle speed, allowing one to back off the idle
> screws a little hence reducing fuel consumption and idle emissions.
Towards
> the end of production the TCSA system was fitted which was to prevent what
> Clausager describes as 'surging' and limits vacuum advance to 4th gear
only.
> But unless it also allowed vacuum through at idle it would remove the
> emissions benefit. It would also cause the revs to rise and fall as you
> moved the gear lever between neutral and 4th. But then if it did allow
the
> vacuum through at idle the revs would drop and possibly stall when you
> selected 1st i.e. to pull away, so maybe it really does open in 4th only.
> Another 'feature' of the solenoid is that when it operates to shut off
> vacuum from the manifold it also opens the distributor side to atmosphere,
> allowing any vacuum already in the vacuum capsule to dissipate.
>
> If you pulled the hose off the distributor at idle in neutral and heard
only
> a momentary hiss then that implies the solenoid is closed but the port to
> atmosphere is probably blocked. A constant hiss implies the solenoid is
> open. If breaking one of the electrical connections to the solenoid makes
> no difference it implies a mechanical problem in the solenoid. If
breaking
> a connection also drops the idle speed to normal that implies the TCSA
> switch on the gearbox is stuck closed, which would be cause for concern as
> that also locks out the overdrive in reverse, and if it isn't doing that
you
> could wreck the overdrive.
>
> PaulH.
>
> ----- Original Message -----
> From: "Steve Gorr" <sgorr2@comcast.net>
> To: <mgs@autox.team.net>
> Sent: Tuesday, June 08, 2004 6:45 AM
> Subject: TCSA & Vacuum advance woes
>
>
> > .... Pull the hose at the distributor and I
> > hear a distinctive hiss and the idle drops back to spec. Isn't the
vacuum
> > supposed to equalize at some point? The fact that it has to get to 4th
to
> > trigger the high idle would seem to indicate that the transmission
switch
> is
> > activating the solenoid properly. Why doesn't the vacuum advance
release?
> > Solenoid sticking?
|