Ford Escort - Why does "check engine" light turn on?

[Tom Cloud]

check EGR (better, check the error codes .... one of the sites
below ought to have the data on checking it ... if not, tell
me and I can e-mail it to you -- or get a service manual

 http://204.255.212.10/~jthorsse/eectest.html
 http://eelink.umich.edu/~p-nowak/eec-efi/eec-efi.html
 http://www.iaw.com/~aubertin/88mgt/eec-iv/eec-iv.htm


>Check the o2 sensor - they deteriorate after that number of miles.  The ECU 
>is trying to go into 'closed loop' mode while you're cruising, (to get 
>stoich fuel/air mix) and it can't get sensible data from the sensor.

 [ snip ]

>Recently I bought Ford Escort 1991 with 1.9 l fuel injected engine. It runs 
>fine,
>but if I drive on the highway at about 60-70 mph "check engine" light comes 


Tom Cloud <cloud at peaches.ph.utexas.edu>