Choke Light ?

[70GMCer]

What would cause the choke light on the dash to stay on while the engine has been running?

This light never goes out....

[Wwes]

Choke heater not plugged into carb will cause this. It's also a proxy for the oil pressure, so if you don't have good oil pressure the light could illuminate.

Check both the carb choke connection and the oil pressure switch.

[70GMCer]

Originally Posted by Wwes

Choke heater not plugged into carb will cause this. It's also a proxy for the oil pressure, so if you don't have good oil pressure the light could illuminate.

Check both the carb choke connection and the oil pressure switch.

My oil pressure gauge is connected to the sender on the block and works fine.

That choke wire is connected to the carb.....

[Palf70Step]

On my 81 there is 2 oil pressure senders. One for the gauge, the second one is for the dash light and the carb choke wire runs thru it. I had to replace the sender for it to clear the light.

I know yours is V8 (mine is 6), but I think they use the same concept for the V8s. Not exactly sure where the second sender is though.

[70GMCer]

Originally Posted by Palf70Step

On my 81 there is 2 oil pressure senders. One for the gauge, the second one is for the dash light and the carb choke wire runs thru it. I had to replace the sender for it to clear the light.

I know yours is V8 (mine is 6), but I think they use the same concept for the V8s. Not exactly sure where the second sender is though.

Maybe the wiring is different on a 83 than a 81.

I know my oil pressure gauge didn't work until I Installed the sending unit onto the back of the engine & is connected by 1 wire. The oil gauge then worked.

There is only 1 wire that is connected on the choke

see my pics. The 1st shows the choke wire connection & then the oil pressure connection in the back. It's the chrome looking thing & a tan wire is connected to that

[70GMCer]

Any other ideas?

[Palf70Step]

The pictures shows what your stock setup should look like and the connector that feeds the factory electric choke. If you don't have the 2 sensors, then someone eliminated one. Now I am told is you are using anything other than the qjet, the choke light function thru the stock wiring may not work. Not sure how your choke is wired, but you may just need to disconnect the bulb if everything else works.

[70GMCer]

Mine is totally different wiring than yours & the harness looks to have never been touched.

I disconnected the wire on the choke & the dash light went out. Maybe the choke isn't working.....

[Palf70Step]

That isn't my truck, that was a 83 C10 info I found on another board. Sounds like it is a choke issue though, from what you are saying.

Try grounding the lead thru a test light and see is the dash light still comes on.

[70GMCer]

Originally Posted by Palf70Step

That isn't my truck, that was a 83 C10 info I found on another board. Sounds like it is a choke issue though, from what you are saying.

Try grounding the lead thru a test light and see is the dash light still comes on.

I'll try that.....thanks

[chengny]

Originally Posted by Palf70Step

The pictures shows what your stock setup should look like and the connector that feeds the factory electric choke. If you don't have the 2 sensors, then someone eliminated one. Now I am told is you are using anything other than the qjet, the choke light function thru the stock wiring may not work. Not sure how your choke is wired, but you may just need to disconnect the bulb if everything else works.

Hey, I recognize those hands - because they're mine. And - not that it really matters - but that is an 86 K30, 350 M with a federal emissions package.

2X Bill's suggestion. That engine should have both a oil pressure sender and also an oil pressure switch.

The oil pressure sender is connected directly to the oil pressure gauge - on the TAN lead. That's all the sender is for - to drive the pressure gauge. It generates a variable resistance in the gauge's sensing leg that is dependent on oil pressure (about 0 to 60 ohms - from 0 psi to maximum system pressure). It has nothing to do with the operation of the choke heater or CHOKE warning light.

It may have been removed at some point, but there should be an oil pressure switch included in the choke heater Choke light circuit. Apparently, up until 1984 it was located just above the oil filter - screwed into the side of the block. In the image below, item 13 is the sender and item 17 is the switch:



When properly wired, the switch functions to supply power to the choke heater immediately upon establishment of oil pressure. Unlike the sender which creates a variable resistance, the switch - which is a normally open type - closes (when oil pressure reaches about 10 psi) and completes the circuit providing power to the choke heater. The operation of the pressure switch/choke heater/CHOKE light circuit is way more involved than the sender gauge circuit. It is explained below - if you are interested.

This system was designed before the advent of ECM's. It was GM's response to the EPA's new mandate that to reduce NOX emissions, the choke had to be opened automatically and as soon as possible after the engine was started. So, I guess they figured that establishment of oil pressure would be a good indication that the engine had fired up. The warning light was most likely a requirement as well. If the light was on after the engine came up to speed, there was a problem with the choke heater. The possibly unintended advantage was that - if the CHOKE light came on while the engine was running, it could mean that engine oil pressure was below 10 psi. A red light coming on in the cluster is more apt to catch the driver's attention than the gauge's needle pegging low.

[70GMCer]

Great explanation & easy to understand how this works.

But, I took the main wiring loom off the harness that all the engine, starter, etc wires are.

There is NO other wire that would connect to the switch that is above the oil filter. In fact, every wire in that harness is connected including the tan wire that is connected to the oil pressure switch by the dizzy. There are NO cut wires at the fuse block at the firewall either.

Now, this isn't a California truck that did require at that smog stuff on it.

This is a Canadian built truck. Maybe they did the wiring different....

At this point, I'm just going to leave the choke wire off the carb choke housing. I'll fool with it later on.

I appreciate all the help on this "Gremlin"

[70GMCer]

I tested and have 12 volts at the choke connection with the key on.

I then removed the electric choke & tested for movement of the spring. It is turning.

So, the electric choke does work.

Still haven't figured out why the dash light stays on, & at this time, don't care. Just going to remove the dash bulb.....

Again, thanks for all of the suggestions