Help! Electric choke

[cstevenson]

Hi all 81 owners, my 81 vette has the original equipment. My choke will not open, and I have replaced the choke, the relay and the fuse. I'm only measuring less than 2V at the choke. Any ideas as to what could cause this? I have cleaned up all terminals to the alternator and battery. Thanks again! Clay

 

[LannyL81]

Does the choke lite come on when starting the engine?

 

[cstevenson]

Yes.

 

[Vette/Berlina-coupe]

1980 Rochester-carb. Electric-choke Not Working..? ---Here's a possible solution...!

The electric-choke was not heating-up, --so removed the three-screws w/retention-clips holding the black Bakelite-disk where the 12v. wire connects, and found the Carb.-rebuilding Specialist had unwittingly installed a circular-gasket where the two C-shaped metal contact-shoes must make contact with the circular-seat receiving the Bakelite-disk; -thus upon reinstalling the Bakelite-disk without the gasket, the electrical-circuit is now completed and the Choke-coil (bimetalic spiral-spring like element) heats-up perfectly!

 

[Peer81]

Start measuring from where on 12v gets to be only 2v. Normally if something is wrong its usualy at the relay.

Greetings Peter

 

[cstevenson]

The electric-choke was not heating-up, --so removed the three-screws w/retention-clips holding the black Bakelite-disk where the 12v. wire connects, and found the Carb.-rebuilding Specialist had unwittingly installed a circular-gasket where the two C-shaped metal contact-shoes must make contact with the circular-seat receiving the Bakelite-disk; -thus upon reinstalling the Bakelite-disk without the gasket, the electrical-circuit is now completed and the Choke-coil (bimetalic spiral-spring like element) heats-up perfectly!

Thanks, for the post. I checked yesterday and there was no gasket.

 

[cstevenson]

Thanks Peter. I checked the voltage at the relay and I have 11.3V at to relay with the car running. So I replaced the relay again and the choke light still remains on, I'm still measuring only 1-2V at the choke, and the choke heating element isn't heating up. I took the choke off and verified that the choke heater works fine when you put 12V across it. The running voltage seems low, could this be a charging system problem? I noticed that the check engine light flickered on when I turned on the A/C, and also the ignition buzzer continues to buzz after the car is turned off and the key removed.

 

[Peer81]

I don't know where the choke relay is seated in the 81? But did you get 12v on the control wire or 12v on the exit (choke) wire?

I'm thinking you have 12v on the control wire but the ground control wire is not connected, that way the relay is not powered on so it don't connect the choke wire to 12v. Your battery current could be low but if you can start the engine then there is enough current to head up the choke.

If you have 12v on the exit choke wire then there is something wrong with that wire (between the relay and the choke).

Greetings Peter

 

[cstevenson]

I don't know where the choke relay is seated in the 81? But did you get 12v on the control wire or 12v on the exit (choke) wire?

I'm thinking you have 12v on the control wire but the ground control wire is not connected, that way the relay is not powered on so it don't connect the choke wire to 12v. Your battery current could be low but if you can start the engine then there is enough current to head up the choke.

If you have 12v on the exit choke wire then there is something wrong with that wire (between the relay and the choke).

Greetings Peter

Thanks Peter, I measured 12V on the control wire only, by unplugging the relay and measuring the terminal. I'll check the choke wire with the relay plugged in and let you know.

Clay

 

[cstevenson]

Thanks Peter, I measured 12V on the control wire only, by unplugging the relay and measuring the terminal. I'll check the choke wire with the relay plugged in and let you know.

Clay

At the choke relay connector with the car running I measured 12V on the control wire, 1V on the choke wire, and 4V on the ground wire. What do you think?

Thanks,
Clay

 

[sd81]

At the choke relay connector with the car running I measured 12V on the control wire, 1V on the choke wire, and 4V on the ground wire. What do you think?

Thanks,
Clay

Hi Clay
I hope you have fixed the problem but if you haven't here is what I've found out. I was doing some work on the center dash and after putting it back together the choke light would not go out and the engine would not idle. After checking many times I thought I'd worked it out to be the relay, a new one was bought but it still didn't work.
Now you say the control wire has 12v, 1v on the choke wire and 4v on the ground. This is what you should find at the relay. The brown wire, top left comes from the generator light in the center dash guage and should have over 12v (mine has around 13.5v) The other brown wire (lower terminal in picture) comes from the fusebox and should have around 12v. If you have both of these with voltage the relay should switch the power to the blue & green/white. This will give power to the carb and turn the light off below the tach. My problem was power coming from the fusebox was around 1.5v, but when I tested the fuse without removing it with a testlight it lit and seemed to be OK. When I removed it and looked at the terminals they had corrosion causing a low voltage to be sent to the relay.
Here's a quick test. If you have 12v to one of the brown wires loop a spare piece of wire from it to the other brown, the relay should switch and then you'll have 12v to the blue & green/white and the choke light will go out.
I hope this makes sense and helps,
Regards, Scott

 

[cstevenson]

View attachment 9729

Hi Clay
I hope you have fixed the problem but if you haven't here is what I've found out. I was doing some work on the center dash and after putting it back together the choke light would not go out and the engine would not idle. After checking many times I thought I'd worked it out to be the relay, a new one was bought but it still didn't work.
Now you say the control wire has 12v, 1v on the choke wire and 4v on the ground. This is what you should find at the relay. The brown wire, top left comes from the generator light in the center dash guage and should have over 12v (mine has around 13.5v) The other brown wire (lower terminal in picture) comes from the fusebox and should have around 12v. If you have both of these with voltage the relay should switch the power to the blue & green/white. This will give power to the carb and turn the light off below the tach. My problem was power coming from the fusebox was around 1.5v, but when I tested the fuse without removing it with a testlight it lit and seemed to be OK. When I removed it and looked at the terminals they had corrosion causing a low voltage to be sent to the relay.
Here's a quick test. If you have 12v to one of the brown wires loop a spare piece of wire from it to the other brown, the relay should switch and then you'll have 12v to the blue & green/white and the choke light will go out.
I hope this makes sense and helps,
Regards, Scott

Scott, thanks for the post, this is very helpful. I did the jumper test you suggested, and the relay did kick on and the choke light went out. Since my low voltage is on the brown wire from the generator light, I plan to pull off the center console and look at the connection at the generator light. Hopefully I'll find the problem.
Thanks,
Clay

 

[sd81]

Scott, thanks for the post, this is very helpful. I did the jumper test you suggested, and the relay did kick on and the choke light went out. Since my low voltage is on the brown wire from the generator light, I plan to pull off the center console and look at the connection at the generator light. Hopefully I'll find the problem.
Thanks,
Clay

Glad it helped, you might find that the printed circuit behind the gauges is burnt. The printed circuit is available for around $70. Be carefull when you are removing the guage cluster as there is a bulb in the top that shines down on the heater control panel. If you don't drop the cluster down before pulling the top out you can split the dash with the bulb holder and end up with a crack in the vinyl.
Scott