I have a used 1990 740 B230F Engine (have had about 1 yr). Several days ago I attempted to start car, it fired, half heartedly, and died. Would just crank over but not fire from there-on. I sprayed starting fluid into air housing and car started but ran very badly and emitted very dark exhaust. There were no prior indications that there was a problem of any kind (at least that I picked up on)in fact since I have had the car I've no problems at all.
Car has about 130k miles and has been taken very good care of. Fuel pumps (2) seem to work, at least I can hear the running and it did continue to run when I started it with starting fluid. Since the initial day this occured I have not been able to start car again even using starting fluid.

I first assumed I had a bad fuel pump relay and this was verified by a Volvo parts person, over the phone, as being a very likely possibility. Anyway I replaced said fuel pump relay with no improvement, still won't start.

I am thinking now that I have a bad ECU but am somewhat reluctant to part with some fairly big bucks without knowing that the unit is bad.

Any suggestions? And is there any way to test the ECU or any place I can sent said unit for testing? Any knowledgable suggestions relating to this problem would be extreamly helpful.

THANKS.

Vg