Nice to be back in the fold again. unfortunately I come here in desparation, and although my problem is with a 156, its still the good old 1.8 16v Twin Spark Unit. Anyway, here's the problem :
When cold, the car starts and runs fine, however when its warm it just manages to idle and runs very rough, if at all at low engine speeds; the throttle is completely unresponsive (its like there's too much air and not enough fuel or a fuel starvation problem) until I can manage to coax the revs upto about 3500, then it runs fine, until you let the tachometer drop below 3000rpm and the throttle becomes unresponsive, and "popping" back can be heard through the inlet manifold. I remember having a similar problem with my 155 v6, which turned out the be the idle solenoid, which had becone gunked up with sludge and jammede open, however, I can't locate this on the twinny engine. I also suspected the temperature sensor, but from experience if that fails it goes to a default setting of about an idle of 2500rpm. I've also cleaned the air flow meter, which hasn't made a bit of difference.
Any help/suggestions would be greatly appreciated.
Would it make any difference if I disconnected the Lambda probe and if I did would it go to a default setting, allowing the engine to run, but albeit at reduced efficiency By the way, where does the idle actuator live on the twin spark unit?
Also forgot to mention before, all this seems to have happened since I replaced the Powerflow back box with the original Alfa part. Also at the same time, the car was fitted with a new front pipe, so the Lambda's been disturbed, which I believe they don't like.