I have an '01 Ford Escape with 3.0L V6 and it is not starting. Can someone help with a wiring diagram for the fuel pump.
-Symptom: Car turns over but there is no fuel pressure. Turning the key to ON position does not always cause the fuel pump to run for a few seconds (no charging of the fuel system).
--Battery is 6 months old
--Changed fuel filter (12/13/08)
--Changed Fuel pump/sending unit (12/13/08)
--Applying 12v directly to fuel pump, run the pump and car starts. Unplug direct 12v while car is running and plug pump back into vehicle wiring and the pump/car keeps running.
--Voltage at battery is 11.9v
--KOVO(Key On Vehicle Off): vehicle supplies 10.9v (assume voltage is higher when engine running do to voltage from alternator)
--Replaced fuse and relay for ‘fuel’ under hood
--No apparent issue with inertia Switch
At 11.9 volts your battery is considered totally discharged.
See this link & put a charger on the battery. A fully charged battery will read 12.6 volts.
http;/www.batterystuff.com/tutorial_battery.html#6
I see that my link did’nt work.
From the chart at the link a fully charged battery will read 12.7 volts.
50% charge reads 12.2 volts
Dead battery reads 11.9 volts.
With engine running you should read around 14 volts.
Thank you. I will check the voltage again this evening. I have a charger and another vehicle in the garage I can connect to to see if voltage is the issue.
The current battery is only 6 months old and the voltage reading was taken while the key was on.
Your post made me curious so I checked key on & off voltage on my 87 Ranger which starts just fine.
Key off 12.51 volts
Key on is about the same as yours 11.84 volts.
My battery load tester simulates voltage with a cranking load.
A good battery holds above 10.5 volts. Mine held at 10.7 volts.
Since your pump runs fine on alternator voltage, but not off the battery I would give the battery a full charge & have it load tested to be sure it’s not the problem.
Since your key on voltage is about the same as mine it seems as if your battery is OK, but I would still get it load tested to be sure.
I found that the ground of the sensing side of the fuel pump relay is the issue. I extended the 4 connections on the relay and put the side that is not 12v (while the key is on) and connected it to the negative terminal on the battery. The pump now runs when the key is on (the whole time the key is on). I also see on the wiring diagram that there is a fuel pressure sensor on the tank titled ‘Fuel tank pressure transducer Sensor’. They both are connected to the PCM and I will try changing the sensor.
Well-performed diagnosis.
Good luck!
If you’re saying that the wire that is normally grounded by the PCM is now wired directly to the negative post it sounds like you’ve allready found the problem, A bad PCM.
Or am I missing something here?
The PCM does ground the fuel pump control relay WHEN it gets the proper signals that other things are ready. No, I don’t have the strategy the PCM uses; but, I could get it from alldata.com for a subscription of $25 per year (or, at my public library, for free).
By direct wiring the fuel pump relay, the fuel pump will fail sooner than otherwise.
Can anyone supply me the logic/strategy the PCM uses? I am not aware of my local library having an alldata subscription or I would be there more often. I don’t plan on leaving it connected this way for ever. The fuel tank pressure tank sensor is a dealer only item and most dealer part counters are closed on the weekend. The ones that were open don’t stock the sensor. $62 for the sensor and I think I have to drop the tank to change it. There is no reference to in in my Haynes manual.
I dont think the PCM cares about or monitors fuel pressure. Your 2 second pump run is most likely simply controlled by a timer in the PCM.
In your 1st post you said you sometimes get the 2 second prime & sometimes not.
My guess is a flaky PCM or the wire from the relay to the PCM could be going open.
When my neighbors Ford powered motorhome would’nt start & we did’nt see the 2 second ground from the PCM at the relay we found the PCM was shot.
Replaced it and off they went on their trip to Vegas.
Speaking of Vegas:
I saw a picture of OJ looking out from behind his prison bars & a caption that reads:
“What happens in Vegas stays in Vegas.” Gotta love it.
Ditto to what hellokit mentioned about a 25 buck subscription to alldata.
Odds are it would have exactly the info you need for this.
Being that the ground has never been lost once the vehicle is running (i.e. the car never stuppers or stalls once it is running), it may point to the PCM not giving the ‘2 second’ ground being the main issue. I wonder what a PCM costs?
Does the PCM always do the ‘2 second’ fuel pump run or does it only do it if the fuel pressure is low? I am trying to find out if the pcm is bad or if the sensor is intermittently stuck high, therefore telling the pcm there is no need to do a fuel pressure ‘2 second’ run.