nosnow

My MPG gauge is acting strangely and I am trying to figure out if it is telling me there is a problem. The car is an '82 5-speed and the gauge functions normally but shows extremely high fuel usage. It starts out with normal consumption after warm up but after 5-10 minutes shows high fuel consumption. This usually lasts for about 30 minutes and then goes back to normal. The difference is significant as it reads 8mpg in 5th at 70 and then it will revert to ~25mpg in 5th after 30min. This only happens in the morning, the gauge works fine when I drive home from work. The car drives and responds normally and I get about 16mpg mix driving.

Questions:
- How does the gauge get the reading? I've read through the threads and some say it is vacuum and some electronic... not sure which.
- If there is a vacuum connection where is it located?
- Could this be telling me that the cold start valve is sticking or that I have a leaking injector?

marton

probably the instrument pod has a bad earth
it is definitely electrical; pull the fuse for the interior lights and the mpg gauge stops working

Marton

nosnow

I guess I'll be fixing my interior lights also... They never worked but it sounds like the problem maybe connected.

marton