Ignition problem of Celica 1985

[quangnguyen]

The timing of my Celica 1985 is always about 30 degrees when engine is at idle. I used timing light to adjust it to 5 degrees, but the engine will stall when I shift the lever. When I adjust timing to 10 degrees, my car can run, but engine loses power and burns too much gas( around 15 miles per galon).
If I don't adjust timing( 30 degrees), the idle is very rough, and it burns about 19miles per galon.
This car was over heat and somebody fixed it before itis mine.
Please give me some advice or main reasons.
thank you very much.

[Pineapple]

Check procedure on how to set timing and idle. I can tell you're doing it wrong. You need to short 2 connection in diagnostic plug before you start. Buy or borrow a Haynes manual.

[quangnguyen]

Thank Pineapple!
I am easy to find diagnosis box where I conect 2 terminals on my camry, but I can't find it on Celica 1985. I also came to Kragen and Autozone, but they don't have any book that talks about Celica 1985. Maybe this car is too old.
May you show me where it is? If you can, give me a picture please.
Thanks again.