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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.

Background:

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?
 

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Discussion Starter #2
2002 Taurus SES, Vulcan, 109,000 miles.
Update. It did it again, stranding me 4 miles from home.

Torque reported fuel pressure at about 8 PSI. Key on key off ten times had no effect. Banging on the fuel tank had no effect – I was monitoring the pressure with Torque. Tapping then under hood sensor had no effect. Tapping the controller in the trunk had no effect. But it did learn that the trunk light is hot enough to put a fine blister on my arm. :-|

One thing I did notice was that the pressure crept up, maybe .2 psi per minute, with the key on but not trying to start the motor. It eventually got up to 17.8. The motor would briefly start, then quit.

The good news is that it restarted after sitting for 45 minutes. Fuel pressure was 45 PSI.

Now I get a P0191 error Fuel Rail Pressure Sensor Circuit Range/Performance.

So what does the P0191 error mean? Simply that fuel pressure is low? Or does P0191 make a specific component more likely?
 

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On my way to get a Haynes manual for my taurus. I don't know much about Ford fuel system, but I bet you have a regulator issue. When the fuel pressure is low, but endine running, is the idle low?
 

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Update. It did it again, stranding me 4 miles from home.

Torque reported fuel pressure at about 8 PSI. Key on key off ten times had no effect. Banging on the fuel tank had no effect – I was monitoring the pressure with Torque. Tapping then under hood sensor had no effect. Tapping the controller in the trunk had no effect. But it did learn that the trunk light is hot enough to put a fine blister on my arm. :-|

One thing I did notice was that the pressure crept up, maybe .2 psi per minute, with the key on but not trying to start the motor. It eventually got up to 17.8. The motor would briefly start, then quit.

The good news is that it restarted after sitting for 45 minutes. Fuel pressure was 45 PSI.

Now I get a P0191 error Fuel Rail Pressure Sensor Circuit Range/Performance.

So what does the P0191 error mean? Simply that fuel pressure is low? Or does P0191 make a specific component more likely?
Highly likely fuel pump temperature sensitive. Needs replaced. I am relatively sure it is a variable volts managed pressure with a sensor on the fuel rail with couple wires and a vacuum hose to it. Very reliable part. There is a control box behind the rear seat, pas side in sedan, and behind the store box in the wagon, pas side. Not likely to fail.

Pumps have lot more fail to run when sitting hot than other times. No so likely to fail while driving.

-chart-
 

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Discussion Starter #5
On my way to get a Haynes manual for my taurus. I don't know much about Ford fuel system, but I bet you have a regulator issue. When the fuel pressure is low, but endine running, is the idle low?
Mostly it is all or nothing. Runs great or won't run at all. When it does run with low pressure, it usually dies quickly, or runs so bad it won't drive more than about 200 feet before it dies.
 

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Highly likely fuel pump temperature sensitive. Needs replaced. I am relatively sure it is a variable volts managed pressure with a sensor on the fuel rail with couple wires and a vacuum hose to it. Very reliable part. There is a control box behind the rear seat, pas side in sedan, and behind the store box in the wagon, pas side. Not likely to fail.

Pumps have lot more fail to run when sitting hot than other times. No so likely to fail while driving.

-chart-
Thank you, thank you, thank you. I was having such a hard time understanding how and why the engine being warmed up affected the fuel pump. The problem isn't that the engine is warmed up. The problem is that the fuel pump is warmed up.
 

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What type of fuel filter do you have, does it have two or three hose connections. All my 2001s failed the fuel pumps in the exact manner you described at 100k miles. The one started with starting fluid and ran perfect and did it again in a week. That time it didn't start with fluid but after two hours it started perfectly. Replaced pumps in both cases and never had a problem again. 2001 had a special system and was wondering if it carried over on yours. The three connection filters have a regulator in the tank.
 

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What type of fuel filter do you have, does it have two or three hose connections. All my 2001s failed the fuel pumps in the exact manner you described at 100k miles. The one started with starting fluid and ran perfect and did it again in a week. That time it didn't start with fluid but after two hours it started perfectly. Replaced pumps in both cases and never had a problem again. 2001 had a special system and was wondering if it carried over on yours. The three connection filters have a regulator in the tank.
Yeah, I am now convinced that unfortunately it is the fuel pump.

I don't know which fuel filter I have, the kind with external clips or the three point internal that requires special a tool.

Since I have the FPR in the trunk, I am guessing that I don't have the three point internal connector. I will update when I know for sure which filter I have.

Meanwhile, for anyone interested, here is a good video that shows how to use a Sharpie cap make your own special tool to remove the internal clip quick connect type.

https://www.youtube.com/watch?v=hkZRSMGqQ0E
 

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What type of fuel filter do you have, does it have two or three hose connections. All my 2001s failed the fuel pumps in the exact manner you described at 100k miles. The one started with starting fluid and ran perfect and did it again in a week. That time it didn't start with fluid but after two hours it started perfectly. Replaced pumps in both cases and never had a problem again. 2001 had a special system and was wondering if it carried over on yours. The three connection filters have a regulator in the tank.
The '01 is a one year only, 3 nipple filter, semi return system pressure bypass regulated in the filter and some returned to the tank.

If a car has the pressure sensor on the fuel rail, it will have FPM behind the pas rear seat, or in the back pas fender of the wagon. Pressure sensor has wires and a vacuum hose on it. OBDII can read out pressure on '02 and later. '02 is like '03 and later. Of course, what kind of hairpin is on the filter lines is a "Surprise". (Sold separately)$$$.

-chart-
 

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The '01 is a one year only, 3 nipple filter, semi return system pressure bypass regulated in the filter and some returned to the tank.

If a car has the pressure sensor on the fuel rail, it will have FPM behind the pas rear seat, or in the back pas fender of the wagon. Pressure sensor has wires and a vacuum hose on it. OBDII can read out pressure on '02 and later. '02 is like '03 and later. Of course, what kind of hairpin is on the filter lines is a "Surprise". (Sold separately)$$$.

-chart-
Thought so but wasn't sure if it was a carry over or an early 2002.

Is your Vulcan a fuel flex vehicle?
 

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Discussion Starter #12
The '01 is a one year only, 3 nipple filter, semi return system pressure bypass regulated in the filter and some returned to the tank.

If a car has the pressure sensor on the fuel rail, it will have FPM behind the pas rear seat, or in the back pas fender of the wagon. Pressure sensor has wires and a vacuum hose on it. OBDII can read out pressure on '02 and later. '02 is like '03 and later. Of course, what kind of hairpin is on the filter lines is a "Surprise". (Sold separately)$$$.

-chart-
Ok, turns out that I have the duck bill type connector on my fuel filter. Both came off without breaking. The wix filter I bought has two new clips that look like they will probably work.
 
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