03 MarBosch PWM Idle Valve
The car has been off the road since 2014, and one of the last things I needed to refine was the operation of the PWM Idle valve (I used a Bosch 0 280 140 516 from a Volvo). I’d managed to get it to work somewhat okay, helped by adding a restrictor in on the output (I think it was a piece of 1/2″ fuel hose). These were the last settings I had for it, which seemed to work more or less okay, but weren’t perfect.
The trouble with it is that closed loop idle doesn’t work if your fuel tables aren’t right, both at warmup and normal idle. If they’re wrong it will have a tendency to oscillate and ‘hunt’ up and down. I honestly can’t remember whether I had the problem with the tune at this point in time, but hopefully these settings will give someone a baseline to try improve on getting the thing calibrated correctly.
It also needs a diode wiring in – see here http://www.msextra.com/forums/viewtopic.php?f=71&t=48680&sid=fa9ff145266efd188b22923e183b98b6&start=20 for more info on that.