Hi, is it possible to tell if the ECU is running in cold or hot mode on a 1993 4.0L?

 

Hi pwb.. I don't have the answer but I have the same question. Ever since I re did my cooling system, the old buggy's been running tooo coool. Always under 200. I suspect it might be stuck in the 'rich running condition'. Hope someone helps us out.

 

Unless its effecting performance, i would leave it alone. These jeeps have lots of overheating problems, I take it as a blessing that mine runs too cool.

Neitherless, did you replace the Tstat? If so did you use a 160, 180, or what?

 

195 stat.. I got my Laredo with a blown head gasket and a lot of other 'poor maint' problems. I did a LOT of work on it, and i'm proud to say it's now in showroom condition (if your showroom is at Honest Bob's Used car extravaganza)
But seriously folk.. I love that it runs xtra cool, but it doesn't get the MPG i'd expect from a 6 banger, and since it runs like a top, maybe it IS stuck in startup mode.. If there's a way to find out, i'll bet I learn it here