New injection installed Looks just like the Webers!

[COBRANIP]

"Open loop" is where the electronic parameters are pre defined and do not change while the engine is running. "Closed loop" incorporates an O-2 sensor and continuously monitors the air/fuel ratio (looking at the exhaust gasses) and makes adjustments "on the fly" according to what the O-2 sensor tells the "computer" the engine needs. Both systems have a return fuel line (to the gas tank) so fuel pressure can be regulated. But that's just a guess...but I did stay at a Holiday Inn last night!

[Aussie Mike]

Originally Posted by COBRANIP

"Open loop" is where the electronic parameters are pre defined and do not change while the engine is running. "Closed loop" incorporates an O-2 sensor and continuously monitors the air/fuel ratio (looking at the exhaust gasses) and makes adjustments "on the fly" according to what the O-2 sensor tells the "computer" the engine needs. Both systems have a return fuel line (to the gas tank) so fuel pressure can be regulated. But that's just a guess...but I did stay at a Holiday Inn last night!

A lot of your modern systems run in mixed mode. open loop kicks in under hard acceleration. Closed loop mode for cruising and economy. There are preset fuel maps in the ECU and the O2 sensor readings tweek these over time. It's called Long Term Fuel Trim. There is only a certain ammount of adjustment the LTFT has over the Map.

The ECU in my car is designed to run with a MAF sensor for extra sensitivity but I've deleted it and run in speed density mode. This is where it uses throttle position, RPM, manifold pressure, intake air temp, knock sensors and a speed density fuel and ignition map in the ECU. The O2 sensors tweek the map over time as you drive it and it tunes itself. The better the map is set in the first place the less adjustment the O2 sensors add.

Cheers