I finally got to where we thought it would start and no dice. Cranks, fuel pump does NOT turn on, fuel pump DOES run if you power it up with a PowerProbe.
There is power at the coils and pulsing current at the plug wires. I do not believe the injectors are firing because it does not try to start after filling the fuel line.

I have been trying to find a wiring harness/pin location diagram for my PCM but all the searches sends me to explorer forum which appears to have disappeared.
I found a PDF on another thread for wiring up a 2000 for using key and PATS transmitter and receiver, I believe I followed it pretty good but not positive I tied the correct wires in at pin 15 and 16 at c111 to power up the PCM.

I thought I saved everything I needed but I saved a lot of links that will not go through.

thanks!

 

1999 Explorer computer will need a PATS module, transceiver and PATS key to start fuel pump and injectors

You can do the 50/50 test to see if its a spark or fuel delivery issue
Spray gasoline or ether(quick start) into the intake and try to start engine
If it starts and then dies its a fuel delivery issue
If it doesn't start then its a spark issue
50/50, instant results, no guessing

PATS module was above glove box in the Explorer or Ranger
Transceiver was around the ignition key slot, it had 4 wires that ran back to PATS module
Computer had 2 wires to PATS module

There is no "work around" for PATS, you either need to get it to work, or you need PATS deleted from the 1999 computer(PCM)

Transceiver and PATS key can just be taped together and connected to PATS module and put out of the way under the dash

The PATS module pin 8 is for the Theft light on the dash, it is a 12v pulse, so the Light bulb is grounded full time, then the PATS module will flash it every 30 seconds or so when vehicle is Parked and locked, to let thieves know its active
If you turn on ignition and PATS test fails Theft Light will flash rapidly
If you can hook up a light bulb to pin 8 it would tell you instantly if you are having a PATS issue, if you let it flash for 60 seconds it will start to flash a 2 digit Code, a 1 followed by 2 to 6 flashes

1996 Ranger didn't have PATS

 

Thanks Ron D. I found another thread where you had furnished a nearly identical PDF for a 2000 for someone else. I compared the two and the wiring colors matched my '99 donor.
I wired up everything except there is no splice inline for wire 16 (S240) as I have it going directly to "Hot at all times" and the same for wire #7 (S205) or (G108) I have it going directly to chassis grd.
I then hooked the #6&5 wires using long jumpers for now to pin 16 &15 at connector C111 at the PCM.
No fuel pump, no start. There is pulsing firing at several sparkplug wires and the fuel pump now runs with 12V on it. Before, after sitting for a year, the fuel would not run and only "clunk" when applying 12V directly to it.

Somehow, I am doing something wrong, or the PCM went bad sitting? like the original donor fuel pump.

I am thinking of going to get a PCM for a 1996 5.0 Explorer and see what happens?

 

Yes, many do get the 1996/97 PCM so no PATS

Fuel pump and fuel injectors are what PATS controls, and on some later models it prevents starter motor activation, disables starter motor relay in engine fuse box

If you are in or near a larger city a local Speed Shop may have a Ford programmer or know someone local who does programming, and they can delete the PATS in the PCM, they can also put in a better tune than factory tune, lol
But check price first, some charge an arm and a leg for tuning

 

Well, I struck out trying to find a local shop to reflash the '99 PCM, several shops said they needed the OBD II data port to diagnose my problem, so, a half day (minimum) on the trailer down and back or a tow charge so, I bought a reman '96 PCM from the local autoparts.

The truck started immediately, so sudden it took me by surprise.
Then, it ran out of gas. The fuel pump still does not cycle on. If I jump wire the pump and pressurize the fuel line she starts every time, then runs out of gas.

At the engine compartment fuse box, there is 12V on one terminal constantly hot for the fuel relay, one terminal becomes hot with key on, 12V also. Relay checks good, I also swapped it with another relay, no change.
The fuel pump has 6.78 volts at the connector for pump supply and 12.2 for fuel gauge side of connector.

The fuel inertial switch was not tripped but the guy we purchased the truck from with a "blown engine" (148K) had the passenger toe kick already off, never registered at the time to ask him why.

I Wonder where to start looking?

There is not much corrosion at all on truck, kind of amazing given its age, however, there were chewed wires in the fuse box. Horn wire completely in two, several other wires hanging by a thread, several more no insulation for an inch or longer. I repaired each wire, one at a time. Total,of (8) repaired.

 

You should see 5-8volts on the 12volt line to fuel pump AFTER the first 2 seconds of key ON
This voltage is from the computer's monitor circuit and has no AMPS just volts

Monitor circuit is usually hooked up at the inertia switch, inertia switch should have 2 wires, 12v IN from FP relay, 12v OUT to the pump
Then a 3rd wire on the OUT terminal, thats the monitor circuit

So it reads like the wiring is OK from inertia switch to pump if you see 6v there with key on

The FP relay socket should have 1 slot with 12v full time, from FP Fuse
Then with key on there should be a 2nd slot that now has 12v, from PCM Relay, this is for the relay's coil
The computer GROUNDS another slot for the coil but ONLY for 2 seconds with key on, then it unGrounds it, until engine RPMs are above 400, engine started, its a safety thing

Ford used two kinds of relays, mini and micro
Micro seen here: https://www.gtsparkplugs.com/images/...lay-wiring.jpg
Mini seen here: https://www.gtsparkplugs.com/images/...ode-wiring.jpg

But both have slots 85 and 86, these are the Coil for the relay, there is no polarity, when one is 12v and the other a ground then coil activates(closes) the relay

When a relay Closes, slots 30 and 87 are connected together, again there is no polarity, this part just an on/off switch, so in this case 30 or 87 would be full time 12v from FP fuse, when relay closes that 12v goes to the other slot which has a wire that goes to inertia switch

Ignore 87a, it may or may not be on your relay, but its not used in this situation in any case

From your description the FP relay is closing for the 2 seconds, and powering/priming the fuel system, so engine starts, but computer is not grounding the FP relay again after RPMs are above 400, so engine dies after it uses up the fuel pressure from priming

Computer uses pin 80 to ground the FP Relay, and wiring is working because you are getting the Prime for the 2 seconds, so problem may be inside the computer, its not grounding pin 80 again after engine is running
This ground wire should be a Light blue/orange stripe wire

 

I don't believe I am getting any prime from pump through wiring system.
I power up the pump with jumper wires on the terminals at hanger, listen for the pump to kind of bog down (assuming line full) then remove jumpers, reconnect the wiring connector.

It it immediately starts then runs a little while, cuts back off.

Without jump wiring the pump, it will never start, no matter how long key is left on, no matter how long you crank.

Neither me or anyone standing next to the tank hears the sign of pumping turning on.

So, should I concentrate on fuse box or inertial switch?

 

Pull fuel pump relay

Jumper slots 30 and 87, you should hear fuel pump come on, if so go to ***, if not leave jumper in place and go to inertia switch and test if either terminal has 12volts, if neither has 12v then wire from FP relay to inertia switch is bad
If only 1 terminal has 12v then inertia switch is bad

At inertia switch
The dark green/yellow stripe wire is the wire from the FP Relay, 12v IN
The Pink/black stripe wire is 12v OUT to fuel pump
You can jumper these two wires temporarily until you get another inertia switch


*** If fuel pump runs with 30/87 jumper in place then problem is relay activation
As said earlier, test 85 or 86 for 12v with key ON, 12v from PCM relay, if no 12v then wire on under side of fuse box is bad
To test for Relay ground at 85 or 86 put volt meter or test light in 85 AND 86, then turn key ON, should see +/-12v for 2 seconds if computer is grounding the relay

 

Hey Ron. Isn't the PAT system available on the '98 explorers also?
​​​​​

 

Yes, if talking about V8 or 4.0l SOHC engine models, not sure about the 4.0l OHV models

 

I jumped out 30 and 87 and fuel pump runs now. I didn't let it run very long, but now the engine just spits and burps without actually running. Like it did several times just 24 hours ago now.

Also, with test light hooked to positive terminal and the probe stuck in fuse box on ground terminal for fuel pump relay, I do not see any flash as if the PCM is initially closing the relay circuit.

Now, with it not wanting to start, is it possible they sold me a bad PCM?

I need a break break for a little while.

 

Fuel pump can be left on as long as you are running correct fuel assembly for the computer

Mid to late 1990's Ford was changing from the 30psi RETURN fuel system to the 60psi RETURNLESS system

Computer is setup for expected fuel pressure, so 30psi or 60psi, if you are running the wrong pressure then you are getting TOO much fuel, or NOT enough fuel

RETURNLESS only has ONE fuel line to engine bay, 60psi
RETURN has TWO fuel lines to engine bay, 30psi

So look up fuel pressure for the year of the new/used computer
1999 5.0l should have the returnless, one fuel line system, intake manifold

 

I knew I had the '99 58-62 psi engine and installed the Explorer pump on the Ranger hanger, changing the float in the process since it sunk in the tank of fuel, pin holes.

I had had asked the question on one or more threads "back in the day" as this project has been spanning a year now.

The PCM I ordered was for a 1996 5.0 Explorer and as I confirmed for you the engine, injectors, fuel filter, fuel line, and pump with regulator is basically a 1999 5.0'Explorer. Roughly 60 psi on a PCM for a 36 psi set up.

What next?

 

Yes, the 1996 Explorer V8 PCM is programmed for 30psi, just looked it up
That sucks

How do you feel about carburetor, lol, just joking

I am sure this comes up with swaps just not sure of the direction to go

You can get an in-line fuel pressure regulator, adjustable 30-70psi, but $80-$180

Also check injectors, make sure the 1996 and 1999 used same injector size

 

OK, this is what I know so far:
Yesterday, using the "new" 1996 auto parts PCM the truck would start and then run out of fuel, then if I used jumper wires and pressurized the lines again, it would start and run until it ran that gas out.

The fuel pump was not heard running pre crank, at all and NO 2 second pressurized boost.

Today, it will not start, jumping terminals 30 and 87 the pump runs.

i completely forgot I have the Autoenginuity for Ford's Diesel and gas, '96-2011.
I plugged her up, selected 1996 Ranger, actually it just came up as that. I then checked for codes and had some where it didn't communicate with this or that and then had a P0230 and P0232 codes.

P0232 Fuel Pump Secondary Circuit High
I then ran a KOEO test and it cycled the fuel,pump as part of the test. Key on, relay in fuse box, connector on the fuel pump.

Among the codes it gave (there were the O2 sensor codes because there is no exhaust) was the P0232 again.

Just for comparison, I removed the 1996 Explorer PCM and replaced it with the 1999 Explorer PCM and when conducting the KOEO test it did NOT cycle the fuel pump and got a P0230 code, Fuel Pump Primary Circuit malfunction.
I then cleared codes and reinstalled the '96 PCM and set up the test as a 1999 Explorer and KOEO test it cycled the fuel pump and I did NOT get a P0232 code.

All the while, at each step of the process it would not start.

"Why did I drop out of second grade?"

 

If you leave the "Jumper" in place for the fuel pump, will it stay running ?

 

Will pump or engine keep running?
With jumper installed, the pump keeps running. The engine won't start and run like on Tuesday.
Nothing else changed other than sitting over night, I made no changes.

 

With Ford's the Primary Fuel Circuit is the relay's Coil, Secondary is the 12volts to Fuel Pump

With Key On the PCM expects to see 12v on its GROUND wire for fuel pump relay(pin 80), if its sees that it won't set a Primary Circuit code
When it GROUNDS the FP Relay it expects to see 12v at the Inertia switch, 12v fuel pump power, if not it will set the Secondary Circuit Low code

Secondary Circuit HIGH(P0232) means inertia switch had 12volts but PCM was NOT grounding the FP relay at that time, you will get this code if you jump the FP relay slots 30 and 87

P0230 Primary Circuit Malfunction, means no 12v at the PCM's pin 80(relay ground) with key on, this would be set if FP relay was unplugged from its socket

 

The fuse box, relay, connector all in place.
With the '96 PCM, either running test as a '96 Ranger, or a '99 Explorer KOEO test cycles and runs the fuel pump, again with no jumpers, relay in place, connector on fp.

For some reason the PCM is not closing the fp circuit just turning key on.Only during KOEO test.
Now, she won't start like she did on Tuesday.

 

Swap the FP relay with Wiper relay if they are the same in that year