l1tech question 05 ST

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Peg Leg

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Huntsville, AL
When you pull the fuel pump fuse, does it enable the anti-theft system on a 05 Sport Trac, after pulling the fuel pump fuse to relieve fuel pressure for changing fuel filter the ST will not start. Have > 60psi on engine side of new filter when cranking engine. A bad fuel rail pressure sensor won't keep it from starting will it. I don't see the frp in the starting wireing diagram.



Thanks



Joe
 
It would not start, but would turn over when I initally removed the fuel pump fuse to relieve pressure, but I assumed it would start when I replaced the fuse, but does not.

Anything else that that would have disabled. Cranks fine, greater than 60 psi at engine side of new fuel filter, but won't start(wont hit a lick)



PL
 
there are only three things needed to make your engine start fuel, ignition and compression.. which one are you missing? Do you have spark? Are your fuel injectors fireing? Maybe try a squirt of starting fluid see if it trys then? Pull a spark plug wire off see if you have spark. You have to start with the basics..:soap:
 
You are absolutlly right, first three things I did



Did the starting fluid, compression in spec, and have no spark.



I think I read on this site that L1tech said that the PAT or anti theft woud mimic a no spark condition, and him being the expert, I thought that pulling the fuel pump fuse may have disabled the PCM , ECM and/or ECU. Did not want to take to a shop unless I had to.



PL
 
Pulling the fuel pump fuse should have no affect on the PATS system. Depending on the PATS system that you have will depend on if the starter gets disabled or not. The ST had a change in the PATS system in 2005 so build date would be important to determine which system it is but it really doesn't matter as looking at the security indicator while tryoing to start the vehicle is enough. If you are trying to start the vehicle and the security indicator is on steady or flashing while you are trying to start it then there is an issue with the PATS. If the light is off then you need to look elsewhere for the cause of the no start.



If you have 60 psi after the fuel filter then fuel supply doesn't sound like your problem unless you have really low volume...yes it is possible to have fuel pressure but no volume. The fuel rail pressure sensor that you see sends the fuel pressure signal to the fuel pump driver module which in turns speeds up or slows down the fuel pump to acheive a certain pressure but being that you have 60 psi after the fuel filter this is not your problem.



Are you 100% certain that you pulled the fuel pump fuse and that you put the fuse that you pulled back in the exact same spot which it came out of? I have seen many seasoned techs...including myself....not put the fuse back in the same spot and cause another problem.
 
I am positive, because I have done that myself, I marked the slot with a red sharpie, I even replaced that fuse with a new fuse, and the pump works great. Same relay and pump sounds as before.



I drove my ST into my air conditioned garage, shut it off, and pulled the fuel pump fuse, tried to start truck, to relieve fuel pressure, and it would not start(I assumed that it would start when I put the fuse back in). I replaced filter and hooked my gage to the engine side of the new filter, replaced the fuse and turned key on, pressure went up to about 12 psi, I cranked the engine and the pressure went up to almost 80 psi and held at about 60 psi until I took gage loose, that indicated that the pump was good so I hooked the engine side fuel line up, cycled the ignition on/off 5 times and then tried to start it, would not start, and it has not hit a lick since. Opened buterfly with my hand and sprayed starter fluid behind it and it didn't even try to start, took middle plug of driver bank and grounded against the block and turned off lights, turned engine over, no spark.



L1, will the ECM/ECU throw a code to indicate where the problem is even though it won't start or does it have to be hooked to a Dianostics CPU at the shop. Hoped it was some strange Ford type safty reset.



I have the Ford shop manual but not the diaganostics manual



L1 where would you start?



The build date is 12/04, one owner(157K miles), and no one else has worked on this truck but me (except for tires).



PL



 
I saw before you metioned you didnt have an inertia switch?(fuel cut off) Just a harness? There is a red "button" on top of that harness you need to press in. Just trying to be sure you tried that. I had to replace that "switch" before. It shorted out. But I've heard that sometimes the button wont stay down(reset) and has to be replaced.
 
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The problem has to be with the fuse that you pulled, after all it ran fine up until the instant that you pulled the fuse. When you turn the key on does the check engine light illuminate? Which number fuse did you pull and where was the fuse box located?
 
L1



When I bought the filter and got ready to replace it, I went to the Battery Junction Box just like the manual and the project said and looked in the owners manual(OM) to locate the fuel pump fuse, ironically the fuse that the OM said was the fuel pump fuse was not there, the slip was empty and so was the relay slip/space. So I asked the ST board for help and a member sent me a newer version/edition owners manual .



The fuse number pulled is 30 in the BJB in front of the the battery(like in the project picture). I did not pull the fuse while the truck was running, I pulled the fuse and then tried to start ST to relieve pressure



The check engine light comes on and the readout for the odometer, after a couple of cranks reads "Check Guages". Battery reads 13.2 volts.



PL
 
Odd that your '05 fuse and relay. Were not where the manual said, they were. I used to pull them when I reflashed my ecu. I dont anymore so I dont remember there slots.

I have an '04. Mine are exactly where the book said. I dont think ford, changed anything. '05 being the last of the gen1's.



So I asked the ST board for help and a member sent me a newer version/edition owners manual .
Click to expand...



Was your owners manual for a different year.?



maybe the spark plugs/ignition coils shorted out when you washed it?
Click to expand...



I have been thinking the same.
 
Build date is 12/04.



This is a one owner(me) ST.



The owners manual says 05 on cover, and the leather pouch says 05.



My truck has several differences than those on this site. both owners manual say I have a Inertia Fuel Switch, but I absolutly do not, plain pop connection,(took it apart and cleaned, no button). My owners manual says fuel pump fuse is in #5 slot(mines empty) and relay # 50B(mines empty). Project says slot #23(mines empty).



No work has been done on this truck except oil/filter change, transmission oil/filter change, air filter change and tires/brakes(2 pair). All work done by me except tires.



PL

 
http://www.motorcraftservice.com/?link=002&urlfile=/pubs/content/~WO5P27/~MUS~LEN/36/05p27og3e.pdf



This is the manual I that I used.



PL
 
You have a late production ST. Fuse #5 on yours is empty. Your fuel pump fuse would be #30, it realistically is the fuse for the fuel pump driver module though. The fuel pump relay, which is in place 46b supplys power to the fuel pump inertia switch which in turn goes through the fuel pump driver module. You do have an inetrtia switch, it is located in the right kick panel. You said you have fuel pressure though so why are you stuck on the fuel supply system? Can you take a picture of your battery junction box and post it?



Diagnostics are going to almost impossible unless you have some way of pulling codes and or looking at the info in the computer.



I still think you may have a problem with a fuse in the wrong spot or possibly even a lose connection in the fuse box itself being that you drove it in, pulled a fuse and now it doesn't start...either that or it is just a huge coincidence that the truck picked that time to crap out on you.
 
I think you are right, or a world class coincidence. I know I put the fuse in the slot it came out of (completes red sharpie mark that I put on slot and fuses directly beside it)



I know I have fuel. I know I have compression, and I have no spark.



Working backward, A low voltage is supplied to the ignition coil by the PCM, the ignition coil step it up and lights the plugs.



I Know that the plugs are not hot.



I need to know if the ignition coil is hot,



And if not is the PCM hot.



If PCM is not hot where does the PCM directly get its current



PCM fuse is good#44) , dont know if PCM relay #54 is good(How do you verify).



I used to have to go out in the field and reseset 50rf relays at substations after they tripped, but these should reset automatically.



I guess work backward and see if I run into fuse #30.



L1, how would you do it short of hooking up to a $10k DCPU?



PL







 
The check engine light is coming on so we know that the pcm is turning on.



The power wire to the ignition coil is red with a light green tracer on it, there should be 12 volts on that wire with the key on and also while cranking. The other 3 wires at the coil respectively control the appropriate coil pack however you would need a scope to see the signal on these wires.



When you crank the engine does the fuel pump stay engaged?



When you crank the engine does the check engine light turn off while cranking?
 
L1



I decided to start from scratch:



1. Took fuel line off engine side of of filter, hooked up gage, turned on key, guage regestered 15psi, cranked engine, guage regestered and ocilatted at 85psi.



2. Took guage off end of test hose, put end of hose in clear jug, cranked engine, fuel pumped into jug strongly.



3.Took #30 fuse out and cranked engine, no pressure and no flow.



4. Hooked filter back up.



5. Removed middle plug, driver side bank, cleaned plug, and cleaned motor mount bolt that I grounded it to. Had wife crank engine, got a very good spark(inadvertly touched plug and it lit me up). I probably didn't have a good ground on the plug the first time I tested it.



6. Attached compression tester to this plug hole, cranked engine, guage regestered and held 142psi.



7. Replaced plug, cranked engine, did not hit a lick.



8. Sprayed starting fluid behind butterfly, cranked engine, did not hit a lick.



Now I'm really confused. I have the three things that I need to start but will not hit a lick, it all started with the #30 fuse removal( it is the fuel pump fuse because when I removed it and cranked the engine the fuel pump did not work).



Now I have no starting point other than the #30 fuse.



I need serious help, there is a logical reason but for the life of me I cant think what it could be.



PL
 

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