Rob,
Not knowing where you are measuring, I can't tell you why you are
getting the readings you indicate. But I can explain the function of
the OD circuit.
With the ignition ON, there is power on the W1 Relay contact,
effectively powering the relay as long as all the switch gating is
satisfied. A brown wire on C1 supplies the voltage to energize the
solenoid once the relay contacts are energized.
The wiring through the series of switches enables a ground source to
complete the circuit for the relay windings. This pulls the relay
contacts together and allows the solenoid circuit to energize and turn
ON the Overdrive.
The switch circuit has the Column switch in series with a parallel pair
of switches at the transmission that determine if it is in 2nd (one
switch) or 3rd/4th (the other switch). The Transmission switches form
an OR-gate meaning that if either of them is on, the circuit is
completed. Therefore, if either of the transmission switches is ON and
the Column Switch is ON, the relay should energize and turn ON the
solenoid to enable the overdrive to work.
You should use an OHM meter to check operation of the gear switches with
the transmission in various gears. This should confirm that it is
working properly. Then perform a continuity check on the column
switch. If all three are in order, you might have a faulty relay or
solenoid.
Good Luck,
Joe Curry
Rob Christopher wrote:
>
> Hi all
>
> Just to fill everyone in on the alternator saga and say thanks to
> everyone for their help.
>
> I visited Brian (our local TR guru) on Friday aft. Sure enough, the alt
> was fully busted. Wouldn't even bootstrap at that point. Having
> nothing pressing, we proceeded to strip it apart again. Tested all
> individual components, regulator, diodes, everything works in
> isolation. With an exasperated voice, Brian declared "So Rob, what do
> you think, why doesn't it work when it's all together?"
>
> "I have no idea, Brian" I replied.
>
> "Well, I've had it. It's the first alt to beat me in 20 years. I'm
> going upstairs to have some coffee. Why don't you put it back together,
> I've already done it 4 times already. It's your turn." he declared.
>
> 15 minutes later, he returned to a reconstructed alt. Into the bench
> test jig and........ IT WORKS! He politely told me to "Get the h*ll out
> of here with it. I don't ever want to see it again." All with a smile
> on his face. Looks great too as he bead blasted the body and painted
> the fan. It's completely new now.
>
> Back into the car and it working great. Up to a point. If I'm stuck at
> a red light for a long time, the red IGN light will glow again when the
> alt output drops below approx 12V. Malcolm Walker described roughly the
> same conditions and he proposed fitting a smaller pulley to the alt.
> I'll be giving this a try, I think, and let everyone know. The idle is
> also a little low on my car so I'll be upping that a bit when I tune it
> up. This may also help out. For now, the amount of time it is charging
> (ie above 1500rpm) is a lot more than idling, so the battery is being
> taxed only slightly to run the car instead of the alt output.
>
> Now the next thing on the list. OD not working. Was under the car on
> Sunday. OD solenoid has a good ground. With the column switch UP, open
> circuit on the other OD connector (disconnected from the solenoid).
> With column switch down, it's grounded(!?!?). Solenoid itself measures
> a few ohms resistance so it appears OK.
>
> Into the passenger foot well, peel the carpet back, locate the
> yellow/green wire and disconnect. Wire to the column switch shows open
> with switch up and 12V with switch down. (OK, I'm getting confused
> here) Yellow/green wire leading into the trans tunnel shows open with
> trans in neutral and grounded (0 ohms on a continuity meter) in ANY
> gear, be it 1st, 2nd, 3rd, 4th, or reverse.
>
> I'm resolved I have to go in under the trans tunnel to see that switch,
> but I'm confused by my readings. If the switch is bad and shorted out,
> I would have expected to blow a fuse when I flicked the column switch up
> and down applying 12V to it. This didn't happen.
>
> How does the switch work to allow the OD to work in 3rd and 4th. What
> happens to that switch when the car is in 1st, 2nd, or reverse? How
> could it be closing for all gears? Is the column switch wired
> correctly? Is it down to activate the OD and up for off?
>
> I also need a tune up desparately. Bear with me as I'm a product of
> Hondas that a tune up consists of changing the plugs and air filter.
> Can someone point me to a URL which describes (in hopefully gorey
> detail) what's involved in a tune up for these cars. What to
> replace/adjust for ignition system? What to replace/adjust for valves
> etc.? My car has been converted to 2" SU carbs (from a Jag I've been
> told) from the stock ZSs.
>
> P.S. I also learned not to mess with fuses unless you have to. I
> didn't know what size fuses to buy so I pulled them out one by one to
> read them. After fiddling for several hours and driving it a bit, I
> noticed the dash lights, driving lights, etc controlled by the dash
> switch no longer worked. Having been behind the dash to pull the
> voltmeter, I thought I'd managed to do something stupid. After a half
> hour of jiggling this and pushing that, I thought "Doh!". Pulled the
> fuse turned it 90 degress and put it back in, lights are back working.
> This may also explain why anything with a purple 12V wire to it is
> flakey right now. Time for a little polishing of the fuse holders I
> think.
>
> Rob Christopher
> 74.5 TR6 (nonworking OD, badly tuned 2" SU carbs, but now a functioning
> alt)
> Ottawa, ON
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Rob Christopher | | | | robc@cisco.com
> Hardware Engineer | .|||. .|||. | (613) 274-4075
> Cisco Systems | ..:|||||||:...:|||||||:.. |
> Ottawa, Ontario |---------------------------| http://www.cisco.com
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
"If you can't excel with talent, triumph with effort."
-- Dave Weinbaum in National Enquirer
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