I just bought a 94 940 w/135000 miles with the Regina FI system that seems to run fine except for an unusual cold start problem. Or maybe not. Maybe it is normal for this system, but I do not think so. When the car is started with the ambient temp below about 50, it will fire fine and the rpm's will go to about 12-1300 rpm's, then drop to about 700 and start 'loping', too rich. It will 'lope' for about 5 seconds or so, correct and then continue idleing about 750 rpm's. The car will drive fine after it stabilizes, and not choke or die. Every other FI car I have driven , if functioning correctly, will cold start, high idle 1000-2000 rpm, then drop to the correct idle as it warms up. This is not a critical situation since the car will drive, but it seems as if something is amiss, and I like to be pro-active on the repairs.
I have ,as per the FAQ on this site and the just about worthless Chiltons manual,tested the IAC,MAP,MAT,TPS, coolent temp sen, and all wiring/connectors etc with my Fluke DMM and all test fine. The trottle body has been removed and cleaned, all vacumn lines checked, fuel press reg checked, and flame trap serviced. New Volvo plugs and wires, air cleaner and fuel filter have been installed. I have not pulled or tested the O2 sensor since it runs great otherwise, and I assume it is running open loop when cold anyway. Is this normal behaviour? IF not, any ideas as to the cause? The only other thing I could come up with was a severe case of valve /injector deposits causing a fuel
soak/rich/imbalance. But it seems to run fine hot. Thanks!