69 z28 choke

[keech]

Hey guys,
    Well, I decided to put my 69 Z28 back to stock.  Put the dz motor back in last Saturday and fired it up last night.   Started right up. I set the timing , broke in the cam and it went perfect.  Drove it and when it got up to temperature the car started to run rich and was trying to stall.
   I pulled over and the choke was closing.    Its like it works in reverse.   As the motor warms up the choke coil pushes the choke rod up closing the choke flap.   I THINK the coil should be up and pull the rod down as the engine warms opening the choke flap.    The repop choke kit I bought was ordered for a 69 302.   Could they be packaging them wrong?    Please help !   Thanks !   Steve

[jdv69z]

When functioning correctly, the bi-metal coil/linkage also lifts up the fast idle cam which holds the throttle partially open and allows the engine to idle at about 2200 RPM when warming up. After it warms up, when you push the gas pedal/operate the throttle, the fast idle cam drops down, allowing the engine to idle down to the normal 900 RPM. On my Z, I've had trouble with the fast idle cam dropping down when the engine warms up. It wants to stay in fast idle mode. The bi-metal coil doesn't function quite right. So I manually install the linkage rod which attaches to the choke plate, and then flip it away after the engine starts. So the choke is set and operates as is should. As soon as I touch the gas pedal, the choke system is disengaged, and the car idles as it should.

[dale_z28]

When functioning correctly, the bi-metal coil/linkage also lifts up the fast idle cam which holds the throttle partially open and allows the engine to idle at about 2200 RPM when warming up. After it warms up, when you push the gas pedal/operate the throttle, the fast idle cam drops down, allowing the engine to idle down to the normal 900 RPM. On my Z, I've had trouble with the fast idle cam dropping down when the engine warms up. It wants to stay in fast idle mode. The bi-metal coil doesn't function quite right. So I manually install the linkage rod which attaches to the choke plate, and then flip it away after the engine starts. So the choke is set and operates as is should. As soon as I touch the gas pedal, the choke system is disengaged, and the car idles as it should.

Jimmy, could you explain that last part again, please? by "manually install the linkage rod..." do you always have to pop the hood and reinsert the rod, or?? I am wondering about mine (when it's done) the engine builder/mechanic has disconnected my choke and said something about "not needing/using it anyway" which I'm not sure I agree with.
Anyway, short of installing a manual choke system (which I've also considered), what is your technique?

[jdv69z]

You are exactly correct. I have to open the hood and slip the linkage from the bi-metal spring into the arm on the carb. At this point I have a factory setup. It starts and idles just like it should, but then I flip the linkage out of the arm on the carb, and once I touch the gas pedal, it idles down. When I would leave the linkage installed like it is supposed to be, I had trouble getting the engine to idle down. Probably because the bi-metal spring wasn't quite uncoiling correctly and was holding the fast idle cam up too far. This was keeping the engine in a fast idle mode.

[firstgenaddict]

There is a fast idle unloader tang which sounds as though it is out of adjustment or sticking.