Posted by Eddie Ronayne on April 29, 2006, 9:15 pm, in reply to "2002 Astra-G 1.4i"
Turned out to be rather simple...
Fitted new EGR Valve and the Datastream changed - feedback was now 1.09V but the car did not improve at all.
Put the old one back in and went scoping - when I got to the MAP sensor it was too high at idle - corresponded to datastream...
Stuck on a vac gauge and vac was 16"Mg approx... The datastream said the same [57 kPa] but as it was not in "Mg I missed it. Known good one had 37 kPa and of course the voltage was different...
Checked valve timing and all marks lined up - however, the lower cambelt cover had been broken previously and made me doubt the location of the mark. Stripped pulley and checked the Crank Sprocket mark and it did not match the pulley - with that one set up correctly the inlet cam was 1 tooth too far advanced... Set it up correctly and made a new mark on cover. Started car and MAP was 35 kPa [18"Mg on gauge]. Idle became stable and everything ok.
I genuinely don't know if I introduced the fault fitting the belt or if it was there beforehand. I think it must have been there all along as I had made my own marks which don't correspond to the new ones... But they did with old mark on lower cover.
Either way, customer has car gone and is happy.
Thanks for responses, E.
PS: ESI says that 0.8-1.6V is ok for EGR feedback.