New fuel pump, same no start issues.

[08harleyf350]

Installed a new electronic fuel pump, just the pump. I cut the red and blk wires and used heat shrink butt connectors to the new pump.
My 1996 4.0 liter explorer is a daily driver, however I do not drive it for a few days in a row at times. I have issues when it sits, it seems as if they fuel pump won't prime after sitting a couple days? I try cycling the key a few times and I cannot hear the humming noise. I have already replaced the fuel pump relay, I can still hear the clicking noise when cycling the key.
I would not think the fuel pressure would be the issue if I CANNOT hear the fuel pump kick on?
Anyone have an idea on electronically what to try checking?
I find it odd that it only seems to do this after sitting a few days.

Thanks in advance guys.

 

[koda2000]

I'd start by checking for power at the fuel pump when the key is turned to ON (will probably take 2 people). If power (and ground) and present at the pump assembly and the pump isn't running, the pump is no good. If your're not getting power and ground to the pump, work backwards from there.

 

[08harleyf350]

Thanks I will try starting at the pump.
After changing to the new fuel pump. I was able to drive the explorer 8-10 miles and start ups were perfect after running a few errands.
I let it sit for a few days, went to start it up for work and after cycling the key a few (4-7 times) I could not hear the fuel pump prime. I waited a couple minutes and gave it one last try, it finally primed. It seems as if it's gonna take me some time to diagnosis this issue if this issue is so intermittent.

 

[koda2000]

A few things to check besides the actual wiring - If we go under the assumption that the pump is not (and was not) the reason for the no-start, then the problem is probably a poor electrical contact issue. You said you'd replaced the fuel pump relay, but did you check the socket it plugs into for corrosion? Just because it clicks doesn't guaranty it's sending power to the fuel pump. Also, the brass contacts in the socket can become stretched and not make a solid contact. To improve contact you can slightly twist the blades on the relay with a pair of pliers. You should also unplug your inertial switch and check it's contacts for corrosion or burnt contacts.

Intermittent electrical problems are a pain to find, but if you go about finding them systematically the answer is there somewhere.

 

[Turdle]

Which brand of new pump did you use? Reason I ask, is I have seen inexpensive ones die-and/or go intermittent right after replacement.

 

[Littlefoott69]

I would spray contact cleaner on your relay and fuse contacts
when was the fuel filter changed ?

and I always recommend this, because it worked for me (contact cleaner)

http://www.explorerforum.com/forums/index.php?threads/2nd-gen-issues-try-this-first.464701/

 

[Rhett]

I'd definitely change the fuel filter. Clogged one can lower fuel pressure enough to make it intermittent / persistent no-start.

Also -- if you have a dirty tank, the dirt can quickly foul the new pump.

 

[koda2000]

I'd definitely change the fuel filter. Clogged one can lower fuel pressure enough to make it intermittent / persistent no-start.

Also -- if you have a dirty tank, the dirt can quickly foul the new pump.

For what it's worth. I've changed 7 Explorer/Mountaineer fuel pumps to date. All on vehicles with around 175k-200k+ on their OE fuel pumps. In examining each of the fuel tanks, I never found the tiniest amount of dirt in any of the tanks. Wiping the bottom of the tanks with a clean white rag showed nothing. I think most modern gas pumps have filters in them. If you're buying your fuel from an old gas station with ancient pumps and tanks maybe getting crud in your tank is more prevalent.

As far as changing your fuel filter, you should always install a new filter and strainer sock with a new fuel pump.