My recently acquired '73 1.7 is running well now after dwell angle, timing, and valves adjusted. Next step is scraping, treating, and painting some rusty spots; seems to be surface except battery tray is toast.

I discovered this unconnected wire that comes out from under the ECU. Can anyone say what it goes to? Could it be the reason I still experience seeking idle until the engine is warm?

Thanks for any help!

For the optional oil temp sensor. Do you have an oil temp gauge (it would be in the center console most likely)?

Oil temperature sender or thats what mine looks like. Connects the sender to the wire harness lead.

so this will go for the factory "taco plate"??
i added a taco plate to the new motor so i'll just run it to this lead? where does it come out and on the interior end and what does that end look like?

mike

Pull the carpet up by the heater handle. there will be a number of wires for the console. That is where the other end of that wire terminates.

If you don't have a console, there was an optional temp gauge that went in the dash.

clay i have a console but not sure if its origanal. does this mean it may terminate in dash area? any idea of color?

mike

As for your 2nd question, I'd like that answer too. My wife's car ('71 - 1.7L) searches up and down for idle when cold, while at other times, it stays at about 2k until warmed-up

sorry for the hijack...
start with the basic vacuum leaks, check the MPS to see if it holds vacuum

Possible CHTS going south, the ECU brain reads the resistance of the CHTS and if it's intermitant the ECU thinks the engine is warm and stps adding extra fuel for W/U.

Perhaps a bad auxiliary air regulator?

it does not terminate at the dash, but in a bundle by the drivers right hip area by the heater lever. i think the color is green/black

Thanks for the input. I don't have the optional oil temp gauge so this wire will remain in hibernation.

As for the idle, I sure would like to resolve this. When starting cold the car will idle fine. Then after a few minutes it will hunt idle to the point it almost will die. Then after warming up well it settles to around 1000rpms (although there is still a very slight fluctuation but I can live with that). Timing and dwell angle were set at tune up. I've gone through to ensure all the hoses are connected. What is the MPS? The CHTS is connected OK; how do I tell if it is bad? I know I am running rich because I have the idle on the ECU turned all the way clockwise in order to keep it around 1000rpms.

Please forgive changing the direction of the thread and thanks for any help.

Manifold Pressure Sensor