Tricking The Ecm

I have little to no backpressure so my o2 sensor gives to lean a reading and kicks the ecm(1993 CHEV - OBD1) into limp mode. My 5.7L is getting about 7 mpg. I want to trick the ECM by sending the correct voltage from the o2 sensor (make my own O2 simulator) to fix my problem rather than having to add backpressure. I know there are simulators for sale but nothing for my model year. If you have any ideas on how to do this, I would certainly like to hear them.

My truck originally had only one O2 sensor, it was just below the drivers side manifold(1 wire). The drivers side header now has it in the collector.

I am no help on the simulator but I would suggest checking the fuel system and the o2 sensor to make sure it just isn't running lean or maybe the o2 sensor is failing. If the o2 sensor goes dead it will send a lean signal to the ECM and the ECM will then add fuel trying to make the signal show rich, (this results in very bad gas mileage). This is just my opinion to get it to work because if you want the best throttle response and MPG then the fuel mixture needs to be right on, only way for the ECM to adjust fuel mixture properly is to know what is coming out of the engine so it knows which way to go (richer or leaner).

your problem isn't exhaust back pressure, it's somewhere else, ie O2 sensor, vacuum leak, fuel filter, fuel pump, injector, ect ect. Any how the end result is a poor running engine, I think you need to do some serious trouble shooting.

Just a thought!

-Mike