73 PCV Valve Failure

[JoMoSqBk]

[raygreenwood]

Lets see if I can clarify this a bit. Actually its really clear in the thread I have...but its a lot of reading so people can get confused.

1. When the switch is properly adjusted......and the throttle is fully closed.....the little contact button on the wiper arm should be maybe a few thousandths of an inch from making contact with the first enrichment contact strip on the circuit board.
You want it to be very close.....because as you start opening the throttle you want as little delay as possible before the wiper arm contacts one of the strips.....so there is no delay between you adding air to the engine...and the ECU adding fuel to go with it.

2. Along with the above condition.....the forked contact switch should be in contact with the rearward pole....the "OFF" pole....of the switch.



SO TO SUM UP:.....when you are at idle with the the throttle fully closed.....you want the circuit board position adjusted so that the contact on the wiper arm is poised within a few thousandths of an inch of making contact with the enrichment strip.....AND....you want the forked inertia switch...in the OFF position.

3. When its ideally adjusted.......the wiper arm contact should make contact with the first mark on the enrichment strip.....SIMULTANEOUSLY ....as the forked switch makes contact with the forward "ON" pole. In reality...having the wiper arm making contact maybe 1/3 to 1/2 degree of rotation before the forked switch makes contact with the "ON" pole....is more reliable.

4. The object of opening and closing the throttle to see where the adjustment REALLY naturally falls.....is to get the built in slack on the shaft and forked contact...to interact with the standard spring pressure of the throttle plate return spring.

While some slack is built into the plastic D-shaped part that attaches to the throttle shaft....some is not....and teh factory slack through the years varies little....which is why you need to readjust the TVS to correctly set it up....and why just using a general factory adjustment and locking the pate down does not work all the time.

5. The only way the TVS makes significant difference in driving....is when its either not working at all...or is seriously out of adjustment. It is a significant part of off the line fuel enrichment.

BUT...through the eons...I have seen more than a few cars with a non-functioning TVS....whose system had been tweaked enough to run....evenly....but with really poor power. So the owner would tweak with the non-functioning switch (usually a wire was broken)....and think that since no matter what they did it made no difference.....that the witch does very little when it is functioning.

No...trust me.....if you unplug the TVS...it will run REALLY ugly.

6. Lastly.....that throttle dashpot/stop.

Do you have an automatic transmission? If memory serves that piece of equipment is for the automatic. Type 4 cars with D-jet have an overly complex combined spring and vacuum unit that does the same thing.

Its function is NOT to be a throttle stop. It should NEVER prop teh throttle open at all. Not one bit.

Its function i to delay the throttle from snapping all the way closed instantly when you come off the gas with foot on the brake coming up to say a stop sign. As you are dropping speed....it takes a moment for rpm to drop far enough that the torque converter fully uncouples enough to unload the engine.

So....it DELAYS full throttle closure for a moment. It slows it down .

From my experience...its a good component...but with age s teh spring weakens.....its almost useless...so....it gets adjusted a little tighter to function properly again...but then props the throttle open and screws with the TVS adjustment. In order to make it work right you then need a stronger throttle return spring....which then screws with your pedal feel. Ray

[blues90]