I've been on the trail of a Check Engine light for some time.
From the information I could get on error codes they suggested Air Flow Meter, rich/lean on cylinders 1, 3 & 5 and EVAP valve. I have checked through those things and all looks well. Some of the vac hoses looked rough so I replaced those.
My attention was drawn to a relay clicking in the glove box while the engine was running. Digging around its the fuel pump relay that clicks on and off randomly, not all the time. The off parts of the cycle seem very short as the engine doesn't die, although it is behaving as if its misfiring at times. Looking closer at the fuel pump relay with a meter, it seems to have a steady 12V supply to the coil of the relay when the ignition is on, and when the ignition switch is turned to the starting position the other end of the relay coil drops down to 0.1v. When the clicking happens the reading on the meter jumps up toward 12v. Its a digital meter so it doesn't react quickly to the changes.
I don't have decent circuit diagrams for this car but looking at the info I can see on the web and the Haynes Manual for the Omega V6 with a similar engine; it looks like the cold end of the fuel relay coil goes to pin 3 on the ECU. I guess there might be a transistor in there that turns that relay on.
So I might be looking at trying to replace that transistor, find a dry joint around it somewhere, or replace the ECU.
Any sage advice out there before I dig any deeper or shell out the big bucks for an ECU.
Thanks
Ken
