92’ 4.0 4x4 cranks no start?!?

[RangerdadMick]

Son’s 92 4.0 4x4 was running great then fuel pump went out, replaced it, ran great for a couple months. Then fuel relay went out, replaced it, ran great for couple weeks. Then would just crank, fuel pump wouldn’t come on, no power to relay, no codes given. Sent computer off for reflash... still nothing... help getting frustrated...

 

[Broosedamoose]

Have you checked the fuse and the fuel cut-off switch?

 

[RonD]

Spray fuel into the intake and see if it starts, runs, then dies, this will confirm you have good timed spark and it is a fuel issue, called the 50/50 test, always first thing to do when there is a Crank but No Start

1994 and earlier EEC-IV computers have 3 capacitors that fail after 20+ years, under $5 to replace them, lack of fuel pump relay or relay always on was a symptom of a bad capacitor, this doesn't effect flashing just operation

 

[RangerdadMick]

Have you checked the fuse and the fuel cut-off switch?

Yes, all fuses and fuel cut of switch is good.

 

[RangerdadMick]

Spray fuel into the intake and see if it starts, runs, then dies, this will confirm you have good timed spark and it is a fuel issue, called the 50/50 test, always first thing to do when there is a Crank but No Start

1994 and earlier EEC-IV computers have 3 capacitors that fail after 20+ years, under $5 to replace them, lack of fuel pump relay or relay always on was a symptom of a bad capacitor, this doesn't effect flashing just operation

Will try 50/50 this weekend. Where are the capacitors located?

 

[RonD]

The blue ones seen in picture here: http://www.auto-diagnostics.info/ford_eec_iv

They leak after 20 years and can also corrode the circuit board, but it can be cleaned up, no permanent damage
They are easy to change if you can solder, or if a friend can

 

[Cees Klumper]

Today I decided to open up my original ECU to have a look at those blue capacitors and, sure enough, one was leaking onto the circuit board. There were two, I just unsoldered them and will order new ones to put back in, and see if that solves my 'no cold start 'cuz the fuel pump ain't running' problem:

 

[RonD]

It will solve the problem, for sure

 

[RangerdadMick]

The blue ones seen in picture here: http://www.auto-diagnostics.info/ford_eec_iv

They leak after 20 years and can also corrode the circuit board, but it can be cleaned up, no permanent damage
They are easy to change if you can solder, or if a friend can

Well after sending the computer off to be rebuilt. ReplacEd the fuel pump, fuel relay, fuel pressure regulator, fuel filter. spraying the intake with fuel it will turn over. But it still will not run... arggghhh.

 

[RonD]

But it will stay running if you keep spraying fuel into the intake?
So spark is staying on

Does the CEL(check engine light) go off when cranking or running?
That means computer is getting timing signal from EDIS-6 spark module to time the fuel injectors

If both above is true then you are down to fuel pressure at the injectors
So fuel pump is not coming on or fuel pressure regulator(FPR) is stuck open, so no pressure at the injectors

On OBD1 vehicles there is a way to activate fuel pump relay manually so you can hear it run with engine off and then see if there is pressure at the test port on passenger side of fuel rail, looks like a tires air valve, because it is, a schrader valve and works the same way

The OBD1 connector is in the engine bay on the main wiring harness to/from the computer

Look here: https://www.therangerstation.com/tech_library/OBD_I.shtml

2nd diagram is what OBD1 connector looks like, can have a cap on it that says EEC
Fuel Pump slot is labelled in diagram
If you use a jumper wire to battery negative and ground that slot then when you turn on the key the fuel pump relay will close and fuel pump will come on full time, or until key is turned off

So do that and see if you can hear the fuel pump run if so then CAREFULLY press the pin in on the fuel pressure test port
Should be 40psi pressure in there so it can SPRAY a long way
If there is pressure try to start engine

If no pressure then either fuel pump is bad, on but not pumping, or FPR is stuck open
You can unscrew the IN fuel line on drivers side of intake/fuel rail, put end in a container and then activate the fuel pump again, fuel should come fast
If not then fuel pump is bad or.......line or filter is clogged, long shot

"New" now means NEVER tested, so grain of salt with ALL new parts, yours are the first human hands to touch a new part
Quality control is the warranty now-a-days, "You test it, we will replace it if it doesn't work"

 

[RangerdadMick]

This is the computer we received back from being “rebuilt”. Looks nothing like what y’all have posted, wondering if it either the wrong computer or a different one that should work...