2002 Taurus SES, Vulcan, 109,000 miles.
I've already read behlinla's excellent sticky “Why won’t my car start?”
TL;DR version of my problem: Is part # F8CF-9F972-BH a fuel pressure sensor, or it it also a fuel pressure regulator? If F8CF-9F972-BH is not a fuel pressure regulator, is there a fuel pressure regulator and what is the part number? Or is high fuel pressure a typical symptom of a bad fuel pump?
TL;DR version version stops here.
The whole perhaps too long and overly detailed story with Torque fuel pressure data at the end is below:
The reason I ask about high fuel pressure is that on restarts after the car has been run but sets for a short period of time I am getting big swings in fuel pressure.
I've recently had two no starts after the car sets for short periods (minutes to a couple of hours).
The Android app Torque Pro shows typical driving fuel pressures between 38 and 45 psi
. But restarts after short sets produces variations as high as 82 psi
. It sometimes stays as high as 60 psi
for many minutes.
Two months ago, my Taurus left me stranded with a no start. Car had sat for two hours. Motor turned over great, but it barely tried to start and then would not try to start at all (motor still turned over great.) About three hours later, I returned and got it started with starting fluid (fire extinguisher was at standby). After starting, it ran perfectly.
Since barely low voltage and overfilled gas are known causes of intermittent no start, I bought a battery booster and put it in the trunk. I also stopped rounding off the dollar amount when topping off the gas tank.
Low voltage and overfull gas tank was apparently not the problem. I experienced a no start again last week. This time the car had set for about 15 minutes while I made a quick stop at the grocery. Similar symptoms as before, turned over great, actually started briefly but felt like it was running on about three cylinders. Then it died and would not start. Jumping the car did not produce a start. So much for low voltage.
I returned to the vehicle two hours later, and this time starting fluid would not get it running. Or more accurately, it started but died when the starting fluid was used up (fire extinguisher was again at standby).
I returned next the next day (about 14 hours after the no start), prepared to call for a tow truck. Just for the hell of it, I put the key in the ignition and tried it. Started immediately and ran perfectly.
So I started using Torque Pro to monitor fuel pressure. I have also been trying to reproduce the no start condition in my driveway. I start the car in my driveway, let it warm up for 10 to 15 minutes. Then turn off and let set for 15 minutes or so, then restart.
No luck reproducing the no start, but I have got some very interesting fuel pressure readings.
Torque fuel pressure data:
Typical on the road pressure is 38 to 45 psi
. Using the highest and lowest record function, Torque produces the following:
High . / . Low . . . . Comments
43.1 . . 36.5 . . . Nine mile drive to work
42.2 . . 37.4 . . . Ten minute idle in my driveway
62.2 . . 53.3 . . . Restart after setting ten minutes
65.3 . . 58.7 . . . Restart after setting ten minutes
82.2 . . 23.1 . . . Restart after setting five SECONDS
Also, no trouble codes are stored in the ECU
. No other symptoms noted. Car runs and drives perfectly, except for when it won't start.
All the above makes the think the problem may be with pressure regulation rather than the fuel pump. Unless of course, the fuel pump incorporates the pressure regulation internally.
Due to cost of the sensor ($81 at Rock Auto), and high cost and the substantial labor of replacing the fuel pump ($250 for the whole assembly), I don't want to just guess and shotgun parts onto the vehicle.
I would appreciate all educated and experienced opinions. Is this definitely the fuel pump? Or the # F8CF-9F972-BH sensor? Or something else?