Removing 2006 LS fuel hat?! Help

[Drac]

In addition to my car's overheating issue I am trying to fix, it is also exhibiting a symptom where the fuel pump intermittently doesn't complete the priming process. you can "hear" it start, but it doesn't finish. When you try to start the car it just cranks and cranks. You have to let it sit for like 15 minutes and then it will work. It has only done it a few times in the past weeks, but in the past 2 days, it has done it 4 more times... so I need to get this resolved ASAP. I have a replacement pump I was going to put in, but I cant for the life of me get the damn fuel hat off of the tank to get to the pump. I have searched for answers, but everything I see seems to pertain to the 1st gens, as they appear to have a different release mechanism that secures the sender in the tank.





I am trying to use a screwdriver or socket extension with a hammer to slide the outer ring open to release it to get the sender out, but it is NOT budging at all. I have been bashing on it for 30 minutes to no avail. I even tried to pry up on the tabs to try to release some of the downward pressure it is exerting onto the lid, and I have broken 2 flat head screwdrivers in the process.

Am I missing something here? The first gens look to have a white cap that unscrews. My car- not so much.

 

[joegr]

Did you verify that it was the pump and not the REM?
What you are missing is the correct tool to release the ring: http://www.handsontools.com/Ford-Motorcraft-310-123-Fuel-Tank-Sender-Unit-Wrench_p_20533.html
Gen II instructions: http://deneau.info/ls/s6x~us~en~file=s6xa1007.htm~gen~ref.htm

 

[Drac]

Good lord that tool is expensive.

Well I ended up getting it off... Just took awhile. Got the new pump in and it is priming no problem and the car is running. But just for reference, IF this pump starts to do the same the same thing as the other one did, How do I test the REM? from my research, there is no FPDM, it is built into the REM.

 

[Drac]

Ok well scratch that it is doing it again.......... fml

How do I check the REM and where is it located?

 

[joegr]

The REM is behind the trunk light. I suspect that you need to have the Ford factory scan tools to do any meaningful testing of it.
The fuel pump circuit is more complicated than just the REM. Positive power to the pump is controlled by a relay that is controlled by the REM. I would want to verify that the relay is good and that is not being turned off when you have the problem. Positive power also passes through the impact cutoff switch in the driver's kick panel. Negative power (the ground) for the fuel pump comes from the REM and it uses FETs to PWM this to control fuel pump speed (and thus fuel pressure). So, the first question is are you losing positive power or ground (or both). Also the REM controls the fuel pump based on commands/data from the PCM via the CAN bus. There could be something weird going on that has the PCM telling it to turn off, or (perhaps more likely) there could be some problem with the CAN bus where the REM loses communications with the PCM. Loss of communications probably causes the REM to turn the fuel pump off for safety reasons.

 

[Drac]

Ehhh... Great. :| I suppose it may not be as easy as getting a replacement REM and trying that?

The relay for the fuel pump is an odd relay.. so Ill have to look around and see if I can find one to swap out.