Just wondering... how can I tell if I'm stuck in open loop mode?

I've got the L67 in my fiero and the gas mileage seems poor lately. I know I have the 4spd muncie and thats not helping, but something doesn't seem "right"

Does the computer solely base open/closed loop off of temperature only? Or are other sensors considered?

Thanks!

O2 sensor(s) is one of the sensors that is required for closed loop.

Yes, but what sensors are being scanned in order to get to closed loop in the first place?

coolant temp closed loop is about 150ish,, your idle should be high if your still in open loop... closed loop would be 700-900 depending on tune.. to add coolant temp would be first considered then you have your others 02 etc

[This message has been edited by black88fiero (edited 04-07-2012).]

Hmm maybe I'm not stuck in open loop then.

I originally had the car tuned with the stock pulley... then sometime after I dropped to a 3.4 pulley. Maybe its just not optimizing the extra air its seeing and its just dumping fuel to be on the safe side (rich).

best way to tell would be to grab a scanner and check it once its warmed up

Hm I have an aeroforce interceptor scan gauge.. I wonder if I could check something on there.

quote Originally posted by doublec4: Hm I have an aeroforce interceptor scan gauge.. I wonder if I could check something on there.

Look at your LTFT values. If they are very far from +-5, you would probably have some type of issue.

In terms of open loop or closed... I run open loop to IMPROVE gas mileage as it automatically enables lean cruise on most pcms... It takes quite a bit of problems to pop up before the pcm resorts to open loop mode as well.

Install an Air/Fuel gauge. Details at:

https://www.fiero.nl/forum/A...060206-2-068263.html