Originally Posted by sailorbob
Originally Posted by Stu @ M Developments
CO screw is a global multiplyer and adjusts the entire map.
Seems an odd thing to do, why didn't they ignore the input from the CO screw when going into open loop? Is it a quirk of the Weber Marelli system?
95% of cars out there on Weber Marelli dont have any closed loop feedback. It wasnt available until late 91.
The CO screw simply adds/subtracts from the base fuel map from its central point. It has an adjustment range of approx +-125. All mapping and development should be done with the screw centralised thus a car will need a slight trim either way to fuel perfectly.
The fact is, the data on the chip wont change, and if you have reputable software it will have been tested and developed to do what its supposed to do with an idle emissions figure of "X".
If she is lean on boost with the emissions set as per instructions, dont fook around with the co screw, find out whats acually wrong..
Fuel reg.
Pipework to regs and sensors.
Fuel Pump.
Fuel Pump wiring.
Fuel Filter.
ACT sensor.
Map sensor.
Engine spec change.
Some goon jacked her up on the fuel lines.
The list is endless... but the CO screw wont stop her melting down so stop looking for an easy fix and get her fixed properly.
