A few weeks back I hijacked a car repair thread and mentioned that I suspected a bad fuel pump or pressure regulator on my kid's 2000 Ford Contour. There were a couple of suggestions that helped a bit but he was still having problems in cold weather.
Symptom was that the car was a hard start and ran real rough for 2-3 minutes when it was below freezing. If he gave it lots of gas it would eventually start running right. The computer gave the code P0193 "Fuel Rail Pressure Sensor Circuit High" a couple of times now but then would stay cleared for a while. He had an ODB2 monitor plugged in.
He finally got it home for spring break and we put a fuel pressure gauge on it last weekend. Since it was about 40 out it ran right. Fuel pressure was about 40 at idle (spec 35-45) and the pressure went up when I pulled the vac line off of the regulator.
Today it got cold again so I had him set up the pressure gauge and leave the hood open. Temp was about 25. I went key on and got 5 psi and then it dropped to nothing. Started it and got about 10-15 psi and running real rough. After 20-30 seconds it started running better as the pressure came up.
This is a returnless system with the computer talking to the fuel pump to set the base system pressure. The regulate it again at the fuel rail.
I will be picking up a pump tomorrow. The real fun part is that the factory manual (the real thing) shows a system with a return line so I am hoping that the parts place has the right pump in stock. It looks like we can do the swap through the access panel under the seat. The manual wants the exhaust and tank dropped.
I hate working on cars.....