I have a N/A '91 vert. I am a new owner of my first "7". The previous owner changed many things on the car including a "Borla" exhaust system. A " Check Engine" light is on, presumably for the missing O2 sensor. In turn, the engine is running very rich. Great for performance, not so great for fuel mileage. I am assuming that the ECU is pumping the excess fuel to the injectors because of the missing sensor. Is there a re-programmed ECU or something that can be installed to make manuel adjustments here?
Any help would be appreciated.
Thanks.

 

Check the code: http://www.johnr.com/cpucodes.html. The 02 sensor is not used for anything other than cruising, so its role is limited. Not having one will affect mileage, but not power.

The only programmable version of the stock ECU is an Rtek 2.0: http://www.pocketlogger.com/index.ph...age=2&ecu=S5NA. Otherwise, an SAFC can be used as a cheap means of pulling a little fuel. With either you need a wideband 02 sensor to monitor AFRs after any fueling changes.

 

Thank you for the reply. What about the "check engine" light. Will that turn off? Or is there another way to take care of it? Or will a new ECU from Rtek do that?

 

You need to fix the problem to get the CEL to stay off (ie connecting an 02 sensor).

 

Excuse my ignorance...what does SAFC stand for?

 

air flow converter. and about the comment earlier about running rich Ive heard that you actually want to lean it out very little at higher rpms to get the most power, please correct me if im wron.