The picture posted on "Fastfrog" appears to be almost exactly what I'm looking at in my FSM for a 75Z. (As far as the magnet valves, vacumn lines...etc...etc are concerned) According to the terminology in the FSM it's called a "Fast Idle Actuator". Only time it should be "On" or "Active" is if you have the A/C turned on. If you pull the wrapping tape off of all the vacumn lines and trace the whole bundle of vacumn lines across to the "Fast Idle Actuator" it should be the "D" connection (Rear solenoid and port facing the passenger side inner fender) on the "Solenoid" (Bracket has it stamped on the bracket as well as to which which port it is) On the "Fast Idle Actuator" side it should be labeled "F". Should be one piece of vacumn line approx. 4-5 feet long +/- a few inches.

webdawg1

I have the same vacume cylinder on the left hand side of the picture. My car is a california model (1978) with the factory a/c and manual trans. The small vacuum hose goes to a set of solenoids on the passenger side that seem to be hooked up to the a/c system. Im just guessing but I think that the vacuume cylinder in question activates and increases the throttle slightly when the a/c is turned on, since this load at idle causes the engine to drop RPM considerably. On my car however the arm of the vacuume cylinder has been adjusted beyond the range of the throttle linkage so it has to effect that I am aware of.

Hope this helps.

t_andrews

snip...... On my car however the arm of the vacuume cylinder has been adjusted beyond the range of the throttle linkage so it has to effect that I am aware of.

Hope this helps.

t_andrews

Did you mean to say "no effect that I am aware of?" I only ask because that is how it is set up on my 78.

If that is from a california model, then why does my 280Z that is from Georgia have it?

Or did my car come from Cali? this is puzzleing

The B.P.T. or Bypass Pressure Transducer valve only lets the EGR operate when exhaust backpressure is above a certain P.S.I.

The B.P.T. or Bypass Pressure Transducer valve only lets the EGR operate when exhaust backpressure is above a certain P.S.I.

You are correct; that is what the BPT does. However, if you read the thread again, you'll should note that the question is about the item to the left of the BPT in post #1.

My 78 doesn't have that doohicky. I have looked in my service manual and haven't found anything. I will look some more.

fast idle actuater for the ac?

I have that valve on my 78. It contracts when my AC is on. The manual says the idle should increase by 400 RPM when it is fully retracted (manually while the AC is off). Mine works per spec.

If that is from a california model, then why does my 280Z that is from Georgia have it?

Or did my car come from Cali? this is puzzleing

All California Model 280Z's have a "Floor Temp" sensor light on the panel.

Vicky

ahh screw all that emissions stuff

SHAVE THE INTAKES!

That item is a BPT valve (backpressure transducer). It blocks the vacuum to the EGR valve until there is some pressure in the exhaust system. On some of the early cars with this device they would come unsoldered or detached somehow. Nissan had a recall where they put this brace/bracket to hold the tube against the body. If for some reason you have no tube running up to the transducer from the exhaust or have one of the defective ones have no worries. All that’s happening is that your EGR isn't working. Not good for emissions but unless you have to smog the car or are environmentally conscience your car really won’t care. Some early Fed 280Zs didn't have the EGR and no early car had the BPTD.

The device on the left is the AC idle up. I don't believe I ever saw any Z with a converter that didn't have the floor light. Some of the early 280s had a Catalyst light too. Damn thing came on when a sensor got to a certain temp and tripped a relay. Actually all the early catalytic models had the cat light. Used to have to reset the damn things on brand new cars off the trucks. The guys driving the cars off the boat would start a line of cars and leave em running on the choke while they drove the cars off. On the carburetor cars the fast idle wouldn't shut off by itself in those days and it overheated the cat.