2002 Windstar Fuel Pressure Problem

jchapin · 11-19-2005, 07:03 PM

My 2002 Windstar would not start on three separate ocassions. Initial troubleshooting showed that it is due to a lack of fuel pressure in the fuel rail. Further troubleshooting on the 3rd no-start event showed the following:
* The fuel pump and fuel pump relay fuses are OK
* The fuel pump relay is OK
* When the key is turned on the fuel pump relay engages momentarily but the pump never really gets going
* When there is power to the fuel pump it runs normally and the car will start and run normally
* When the key is turned on there is power (12+ volts) to the coil side of the fuel pump relay. Momentarily this circuit is grounded and there is momentary power to the fuel pump. After about 1 second with the key turned on, the fuel pump is not runnning and the engine won't start.

With the key turned on, if a ground is provided to the coil relay circuit, the relay engages, power is provided to the fuel pump and the car starts and runs normally.

The circuit diagram shows that the Powertrain Control Module provides a switched ground for the fuel pump relay coil circuit. This circuit provides a momentary ground when the key is turned on and then switches open, causing the fuel pump relay to switch off power to the fuel pump. Continuity check of the wire from the fuel pump relay to the PCM shows that the wire is OK. Chassis grounds have been inspected and cleaned -- testing after this action showed no improvement.

My questions are: What input to the PCM causes it to open and close the switched ground for the fuel pump relay? What would the risk be if the fuel pump ran continuously when the key was on -- except for accidents where the pump is shut off by the inertia fuel shut off switch? Does this sound like a broken PCM?

Any help would be greatly appreciated.

12Ounce · 11-19-2005, 08:32 PM

The PCM may itself be losing power.

Investigate the condition of the PCM power relay; it may be failing.

jchapin · 11-19-2005, 08:36 PM

Quote:

Originally Posted by 12Ounce

The PCM may itself be losing power.

Investigate the condition of the PCM power relay; it may be failing.

We just swapped out the PCM power relay and none of the contacts looked corroded...but it still didn't work.

I should also note that there are no fault codes to help us figure out what the problem is.

~manuel~ · 11-20-2005, 01:06 AM

Quote:

Originally Posted by jchapin

My 2002 Windstar would not start on three separate ocassions. Initial troubleshooting showed that it is due to a lack of fuel pressure in the fuel rail. Further troubleshooting on the 3rd no-start event showed the following:
* The fuel pump and fuel pump relay fuses are OK
* The fuel pump relay is OK
* When the key is turned on the fuel pump relay engages momentarily but the pump never really gets going
* When there is power to the fuel pump it runs normally and the car will start and run normally
* When the key is turned on there is power (12+ volts) to the coil side of the fuel pump relay. Momentarily this circuit is grounded and there is momentary power to the fuel pump. After about 1 second with the key turned on, the fuel pump is not runnning and the engine won't start.

With the key turned on, if a ground is provided to the coil relay circuit, the relay engages, power is provided to the fuel pump and the car starts and runs normally.

The circuit diagram shows that the Powertrain Control Module provides a switched ground for the fuel pump relay coil circuit. This circuit provides a momentary ground when the key is turned on and then switches open, causing the fuel pump relay to switch off power to the fuel pump. Continuity check of the wire from the fuel pump relay to the PCM shows that the wire is OK. Chassis grounds have been inspected and cleaned -- testing after this action showed no improvement.

My questions are: What input to the PCM causes it to open and close the switched ground for the fuel pump relay? What would the risk be if the fuel pump ran continuously when the key was on -- except for accidents where the pump is shut off by the inertia fuel shut off switch? Does this sound like a broken PCM?

Any help would be greatly appreciated.

i maybe mis understanding you but i think you are describing a normal condition on most fords. when the key is turned to the "ON" position the pcm energizes the relay for a BRIEF instance.like one or two seconds.the pcm has to be recieving a crank signal in order for it to keep the relay energized.therefore you will only have continuous power at the pump when the engine is cranking. you stated a lack of pressure at the rail, but is there zero pressure or low pressure? can you have an assistant look at the pressure gauge when you initially turn the key to the "on" position, have them verify if the gauge shows any pressure at all even if for a brief instance.because a bad pump can cause pressure to bleed back into the tank instantly, and by the time you get out and look at the gauge it will show zero pressure even though there was some pressure if only for an instance.

jchapin · 11-20-2005, 08:46 AM

Quote:

Originally Posted by ~manuel~

i maybe mis understanding you but i think you are describing a normal condition on most fords. when the key is turned to the "ON" position the pcm energizes the relay for a BRIEF instance.like one or two seconds.the pcm has to be recieving a crank signal in order for it to keep the relay energized.therefore you will only have continuous power at the pump when the engine is cranking. you stated a lack of pressure at the rail, but is there zero pressure or low pressure? can you have an assistant look at the pressure gauge when you initially turn the key to the "on" position, have them verify if the gauge shows any pressure at all even if for a brief instance.because a bad pump can cause pressure to bleed back into the tank instantly, and by the time you get out and look at the gauge it will show zero pressure even though there was some pressure if only for an instance.

Last night after fiddling with the van all day I decided to try and start it one last time and when I turned the key to "on" the pump engaged and it started right up. I let it run for a couple of minutes and then shut it off. I immediately tried starting it again and the pump did not kick in and the van did not start. The whole reason for stating this it to let you know that the system must of been up to pressure last night.

This morning I checked the pressure in the rail and it read zero. I left the pressure gauge on it and my wife turned the key to "on". I did not hear the pump start up and the gauge read zero the whole time.

By the way it amazes me that other people who don't know me are taking the time to hear my problem and help me try to fix it. I really appreciate everyone's help.

12Ounce · 11-20-2005, 09:14 AM

For the $20 it would cost, I sure would like for you to replace the PCM power relay and the fuel pump relay ... with brand NEW ones.

And apply some lubricant to the relay bases.

(Humor an old man.)

~manuel~ · 11-20-2005, 10:23 AM

Quote:

Originally Posted by 12Ounce

For the $20 it would cost, I sure would like for you to replace the PCM power relay and the fuel pump relay ... with brand NEW ones.

And apply some lubricant to the relay bases.

(Humor an old man.)

good call.that way they can be eliminated as the potential problem, and are cheap to replace.

jchapin · 11-20-2005, 10:43 AM

Quote:

Originally Posted by 12Ounce

For the $20 it would cost, I sure would like for you to replace the PCM power relay and the fuel pump relay ... with brand NEW ones.

And apply some lubricant to the relay bases.

(Humor an old man.)

OK I will replace both relay''s...what lubricant do I apply to the bases?

jchapin · 11-20-2005, 12:49 PM

Quote:

Originally Posted by 12Ounce

For the $20 it would cost, I sure would like for you to replace the PCM power relay and the fuel pump relay ... with brand NEW ones.

And apply some lubricant to the relay bases.

(Humor an old man.)

I bought two new relays for the fuel pump and PCM. I applied electronic lubricant to the the four terminal that insert into the sockets for both the fuel pump relay and the PCM relay. I also replaced the fuses for the fuel pump, fuel pump relay, PCM and PCM relay just to rule those out. Unfortunately it still does not start.

12Ounce · 11-20-2005, 04:48 PM

But it will start if you apply ground to the fuel pump relay ?

12Ounce · 11-20-2005, 04:58 PM

Another question: Does the 2002 have a dual,or single, fuel line system?

The future is single-line systems (no return line to tank). My '99 has two-lines. Don't know if any Windstar model year went to single line.

jchapin · 11-20-2005, 05:18 PM

Quote:

Originally Posted by 12Ounce

But it will start if you apply ground to the fuel pump relay ?

I created 4 extension wires so I could check voltages with the fuel pump relay in place. If I plug in all four wires to the relay and then plug the input and output for the fuel pump power (at the socket) as well as the input for the coil power (at the socket) and then touch the 4th wire to the negative terminal of the battery then it starts every time without hesitation. I have done this about 5 times. But there must be some reason that they run the "ground" wire to the PCM instead of just grounding it.

jchapin · 11-20-2005, 05:22 PM

Quote:

Originally Posted by 12Ounce

Another question: Does the 2002 have a dual,or single, fuel line system?

The future is single-line systems (no return line to tank). My '99 has two-lines. Don't know if any Windstar model year went to single line.

There are two lines that attach into the fuel rail and both lines lead back to the fuel tank.

12Ounce · 11-20-2005, 06:35 PM

I would guess that once the engine starts, the PCM is looking for a signal that proves the engine is continously running (CPK or the like) ... but I'm guessing. You would think this would cause a MIL (CEL).

Tomorrow, when my head clears of cognac, I'll try the shop manual for a clue.

12Ounce · 11-21-2005, 04:22 AM

OK. The PCM is supposed to give you a one second start-up period, after which it will maintain the fuel pump if a CKP (CranKshaft Position) sensor signal is received. (Per the Powertrain Control/Emissions Diagnosis Manual.)

Since your car is running OK otherwise, I believe that somehow your PCM is losing this CKP info internally. In other words, the CKP info is used to maintain ignition and fire the injectors ... but lost for the fuel pump drive.

I believe it would be safe enough to just remove the fuel pump relay and insert a jumper to replace the relay contacts.

Also, just for the heck of it ... you might look over the connector to the crankshaft sensor ... easier said than done, as its not easy to reach.

And inspect the harness connection to the PCM. Use some of that lubricant here.

Also, roll back the harness, from the PCM, and make sure the harness has not been damaged against the ac tubing or something else on the firewall. (Mine had.)

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