I was fortunate to find an exact match for my ECU (on my '91 745T) on ebay - and hoped that it would solve the problem of my low idle and glowing oil pressure lamp. (Some of you suggested this, or at least that I try another ECU to see if mine wasn't working right. It also was suggested that if I were to go to the Volvo dealer with this problem they would probably try to put in a new ECU.) The one I got is dated 8-3-2000, with a Volvo label and part number (as well as Bosch number) so it is probably a replacement or rebuilt as the car it came from was a '90 740 turbo.

I am happy to say that the ECU works fine, but the problem is still there, exactly as before. Once the car warms up, the idle goes to about 600 and the oil pressure light glows. It may be that the idle is actually higher but the tach on the car says 600 or so.

My next step will be to get the oil delivery tube o-ring(s?) replaced, hoping that the oil pressure light is on because the o-ring has slipped, as some of you have suggested it might be.

Can anyone please tell me if the Volvo owner's manual of this vehicle is correct in saying that it is normal for the oil light to flicker or glow after hard driving, as long as the light goes off as soon as accelerator is pressed? If so am I worrying about something I shouldn't be worrying about? (That is what my wife tells me.) Have any of you with 740 Turbos had a similar experience with the oil pressure light?

Thanks to all who have been trying to help me solve this problem.
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Darius in Albany NY '86 744 GLE (174K); '91 745 Turbo (164K)