96 Explorer 4.0 4wd - Fuel delivery problem

[RichardsMobile]

I will first say I believe it is an electrical issue.

We have an intermittent fuel issue on our Explorer. It will run for weeks with no issues, then I will stop somewhere
and it will not start. I get it towed and it starts at the shop.
Sometimes it will run for an hour, then quit, sometimes 40 seconds, sometimes weeks.

Fuel pump replaced (Good quality)
Fuel Filter replaced.
Fuel line delivery tested.
Rubber lines replaced a couple of years ago.
Relays replaced and relay wiring confirmed good.
ECU connector cleaned and dialectic grease applied.
ECU connections looked good. No "burns" @ 1 year ago
Emergency cut-off switch tested - good

We (my current mechanic) put a meter on the power wire at the relay and sometimes it has power, sometimes not.
ECU Problem? I will replace the ECU anyway, having some 4WD issues that may stem from there.

Any ideas where the best place to get an ECU from?
Any ideas whatsoever?

 

[Fix4Dirt]

I will first say I believe it is an electrical issue.

We have an intermittent fuel issue on our Explorer. It will run for weeks with no issues, then I will stop somewhere
and it will not start. I get it towed and it starts at the shop.
Sometimes it will run for an hour, then quit, sometimes 40 seconds, sometimes weeks.

Fuel pump replaced (Good quality)
Fuel Filter replaced.
Fuel line delivery tested.
Rubber lines replaced a couple of years ago.
Relays replaced and relay wiring confirmed good.
ECU connector cleaned and dialectic grease applied.
ECU connections looked good. No "burns" @ 1 year ago
Emergency cut-off switch tested - good

We (my current mechanic) put a meter on the power wire at the relay and sometimes it has power, sometimes not.
ECU Problem? I will replace the ECU anyway, having some 4WD issues that may stem from there.

Any ideas where the best place to get an ECU from?
Any ideas whatsoever?

imo get pcm from a JY its very far and few when they are bad, so unlikely youll get another bad one imo

 

[RichardsMobile]

imo get pcm from a JY its very far and few when they are bad, so unlikely youll get another bad one imo

But then it has to be programmed, yes? Cost?

 

[Turdle]

Check the large square connector near center of firewall. Make sure all pins are clean and center bolt is tight

 

[RichardsMobile]

Already done. Please see post.

 

[Turdle]

Already done. Please see post.

I see PCM connection listed but not the one I'm referencing.

 

[C420sailor]

Define ‘power wire at the relay’ as it can be interpreted in a few ways

 

[RichardsMobile]

Define ‘power wire at the relay’ as it can be interpreted in a few ways

Quite right. Power from PCM intermittent. Power from battery, OK

 

[RichardsMobile]

I see PCM connection listed but not the one I'm referencing.

Learn me something .... to which were you referring?

 

[RichardsMobile]

Learn me something .... to which were you referring?

OK, We refer to the same connector on the firewall....

 

[RichardsMobile]

OK, We refer to the same connector on the firewall....

I know of that "computer" in the firewall, is there another? My F150 has something behind the fuse box that controls 4WD and drivetrain...

 

[Turdle]

Sorry if I added confusion. 2nd gen issues? Try this first!

Maybe this will help. I was referring to the square connector above intake manifold.

 

[RichardsMobile]

OK. I need to purchase a PCM. Does anyone have a trusted source?

 

[Turdle]

OK. I need to purchase a PCM. Does anyone have a trusted source?

Very rare for a failed PCM . I'd try salvage yards.

Car-part dot com

Just be sure the year and engine are same, there is a 4 digit code on PCM make sure it also matches

 

[Fix4Dirt]

JY id try first

 

[Turdle]

OK. I need to purchase a PCM. Does anyone have a trusted source?

Crack your PCM open, see if you can post pictures of both sides on circuit board

 

[RichardsMobile]

It's at the garage. I'll grab it tomorrow or Thursday.

 

[Mr. Alligator]

Could this be crankshaft position sensor causing issues? Please let us know how this is,resolved.

 

[410Fortune]

allright Ill jump in here see if I can help
the ignition switch is turned to run or start, the EEC/PCM relay fires up and powers the computer
The PCM then controls the fuel pump with a ground signal to the fuel pump relay

It sounds like you are having an intermittent issue with the signal wire from the pcm to the fuel pump relay?

the battery power for the fuel pump goes through the fuel pump relay, then the inertia switch, then to the fuel pump

I assume you have changed the fuel pump relay (you said "changed relays") but you have also inspected the pins the relay plugs into?
Have you opened the bottom of the power junction box to inspect the wires? pins and connections?

You should also do a continuity test on the pcm to fuel pump relay signal wire (LB/OR), should be pin 80

Next would be to remove the pcm, open her up and have a look at the circuit boards/resistors/capacitors