4.0 SOHC to 4.0 OHV Engine will Crank but not Start, Fuel Pump Relay and Fuel Injectors not Firing

[gkorgood]

Hey all, I'm at a loss. Swapped my known good 4.0 OHV out of my crashed 2000 4x4 into a newly acquired 2002 FX4 which had a blown head gasket on its 4.0 SOHC (but ran *just* well enough to get it on and off a trailer). Both manuals, swapped PCM appropriately, using the 2002 body side connector to the 2000 engine harness. At first the starter wouldn't fire, we were able to ground the starter relay from where it was trying to get ground from the computer through the body to engine connector but the 2000 doesn't have that pin. We've confirmed we have crank and spark, and that the fuel pump and its relay work by jumping it directly. When key is in the run the fuel pump relay immediately clicks on and off (not the 2-3 second prime we're expecting, a rapid double click, on-off). We think the computer is shutting off the fuel pump, maybe because of something with PATS (the 02 has it, but the 2000 didn't) but we can't seem to confirm that or think of anything else it could be. Can't check OBD2 codes because the OBD system doesn't seem to be getting the right handshake to initiate, we think that might also be related to PATS. Any help you gurus can provide is greatly appreciated.

 

[Josh B]

You will get plenty of excellent help in time, but it is Saturday evening

Are you in the military there? Welcome to TRS btw

I'm wondering why you didn't just change the head gaskets ?

 

[gkorgood]

I am in the military here.

And I didn't change the head gaskets because the SOHC is a ticking time bomb anyways with the timing chain guides, as well as a personal preference for pushrods over overhead cams

 

[RonD]

Welcome to TRS

And thank you for your service

You will be running into a few issues with the 2000 PCM in a 2002 Vehicle
Yes, had to ground starter relay that was external for PATS

I assume you are using 2002 engine fuse box?
And 2002 cab fuse box

PATS was in the PCM in 2002 so with the 2000 PCM in place the fuel system should work OK, no PATS
So when you turn the key to RUN the fuel pump relay just clicks on and off fast?

Is the PCM relay coming on and staying on, it powers(12v) side of fuel pump relay?
You can tell if the CEL(check engine light) comes on and stays on, that means PCM is powered up and staying powered up

 

[gkorgood]

Welcome to TRS

And thank you for your service

You will be running into a few issues with the 2000 PCM in a 2002 Vehicle
Yes, had to ground starter relay that was external for PATS

I assume you are using 2002 engine fuse box?
And 2002 cab fuse box

PATS was in the PCM in 2002 so with the 2000 PCM in place the fuel system should work OK, no PATS
So when you turn the key to RUN the fuel pump relay just clicks on and off fast?

Is the PCM relay coming on and staying on, it powers(12v) side of fuel pump relay?
You can tell if the CEL(check engine light) comes on and stays on, that means PCM is powered up and staying powered up

Staying on, CEL stays illuminated

 

[RonD]

I will attach the 4 wiring diagrams for 2000 4.0l
and then the 4 for the 2002 on next post

 

[RonD]

And the 2002

 

[RonD]

Oh shoot, I am an idiot

Yes, it is a PATS issue, 2000 PCM needs its PATS module found above the glove box in the Ranger it came from
They are a matched set
If you still have the 2000 vehicle then you can hook it back up
PATS wiring below
PATS disables FP relay but ALSO fuel injectors,, so no work around for the fuel injectors

If you can't get the matching PATS module then you may want to find a 1998 4.0l PCM for manual or automatic whichever you have, you will also need to add a wire and use a new 3 wire Cam sensor and synchro as they change to 2 wire Cam sensor in 1999 with addition of PATS, and 1998 PCM can't "understand" 2 wire signal, literally AC and DC difference


You will also need to deal with speed system
2002 Rangers got speed signal from the PCM, which is gone
Older PCM needs a speed signal, as does speedometer, and cruise

The 2002 transmission will have an OSS(output shaft speed) sensor at the top rear of trans, 2 wire sensor
But its output is 25,000-30,000ppm(pulses per mile), the computer, speedo, and cruise need 8,000ppm
There are speedometer signal interfaces, like the SGI-100BT, seen here: https://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=1192/mode=prod/prd1192.htm
It can convert the 25-30k down to 8k

 

[gkorgood]

Oh shoot, I am an idiot

Yes, it is a PATS issue, 2000 PCM needs its PATS module found above the glove box in the Ranger it came from
They are a matched set
If you still have the 2000 vehicle then you can hook it back up
PATS wiring below
PATS disables FP relay but ALSO fuel injectors,, so no work around for the fuel injectors

If you can't get the matching PATS module then you may want to find a 1998 4.0l PCM for manual or automatic whichever you have, you will also need to add a wire and use a new 3 wire Cam sensor and synchro as they change to 2 wire Cam sensor in 1999 with addition of PATS, and 1998 PCM can't "understand" 2 wire signal, literally AC and DC difference

I do have the 2000 still, is this issue solved as simply as swapping the pats modules between the two? I had the 2002 pats module out thinking unplugging it would solve it but it didn't, so I put it back. Will they interchange or will the 2000 not play nice with the 2002 key?

You will also need to deal with speed system
2002 Rangers got speed signal from the PCM, which is gone
Older PCM needs a speed signal, as does speedometer, and cruise

The 2002 transmission will have an OSS(output shaft speed) sensor at the top rear of trans, 2 wire sensor
But its output is 25,000-30,000ppm(pulses per mile), the computer, speedo, and cruise need 8,000ppm
There are speedometer signal interfaces, like the SGI-100BT, seen here: https://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=1192/mode=prod/prd1192.htm
It can convert the 25-30k down to 8k

I can deal with not having a speedo for a little bit until I can get that converter. Will it hurt anything if the 2000 sees the 25-30k signal until I get it or will it just make my speedo read 3 times faster than I'm actually going?

 

[RonD]

2001-2003 don't have PATS modules, not sure what you pulled out, PATS is inside the PCM in these years

1999/2000 had PATS module above glove box
1999/2000 PATS system seen here, transceiver and module: https://www.ranger-forums.com/attachments/8-cylinder-tech-34/207131d1501478610-photo-log-pats-installation-img_5197.jpg

You need to give PATS module full time 12v and key on 12v and a ground
Hook 4 wires from Transceiver(key slot) to module
2 data wires to PCM
The THEFT light on dash is also a "trouble" light so its good to have working(dark blue/light green wire)
Don't need the Starter Relay Ground wire(pink/orange wire)

You can use either transceiver, 2000 or 2002
You should be able to swap key cylinders from 2000 to 2002 so you can use a "registered" key in 2000's memory

If system is hooked up correctly THEFT light on dash should flash every 3 to 5 seconds, key off
With key on THEFT light should come on and then go OFF if key in ignition is recognized by PATS
If THEFT light starts to flash rapidly then there is a PATS issue, leave key on and wait 45-60seconds and the THEFT light will start to flash a 2 digit code, 11 to 16

11 Transceiver [transponder coil] not connected, or there is no power to it.
12 Transceiver internal fault.
13 No Key/no PATS key has been used to turn the ignition switch.
14 Incomplete key code received.
15 Invalid key code received.
16 CAN communications error

 

[gkorgood]

2001-2003 don't have PATS modules, not sure what you pulled out, PATS is inside the PCM in these years

1999/2000 had PATS module above glove box
1999/2000 PATS system seen here, transceiver and module: https://www.ranger-forums.com/attachments/8-cylinder-tech-34/207131d1501478610-photo-log-pats-installation-img_5197.jpg

You need to give PATS module full time 12v and key on 12v and a ground
Hook 4 wires from Transceiver(key slot) to module
2 data wires to PCM
The THEFT light on dash is also a "trouble" light so its good to have working(dark blue/light green wire)
Don't need the Starter Relay Ground wire(pink/orange wire)

You can use either transceiver, 2000 or 2002
You should be able to swap key cylinders from 2000 to 2002 so you can use a "registered" key in 2000's memory

If system is hooked up correctly THEFT light on dash should flash every 3 to 5 seconds, key off
With key on THEFT light should come on and then go OFF if key in ignition is recognized by PATS
If THEFT light starts to flash rapidly then there is a PATS issue, leave key on and wait 45-60seconds and the THEFT light will start to flash a 2 digit code, 11 to 16

11 Transceiver [transponder coil] not connected, or there is no power to it.
12 Transceiver internal fault.
13 No Key/no PATS key has been used to turn the ignition switch.
14 Incomplete key code received.
15 Invalid key code received.
16 CAN communications error

Found the module in the 2000, the 2002 had this module in the same spot. Got some diagrams off Alldata as well. 2002 Anti Theft Wiring Diagram, 2000 Anti Theft Wiring Diagram, 2000 PATS Connector Pinout, 2002 Central Security Module Pinout (C274a), 2002 CSM Pinout (C274b).

Trying to figure out the minimum number of wires to move around and my head is in circles...

 

[RonD]

Central security module is not part of PATS
You need to leave that connected, as is, its part of the Keyless Entry(Fobs) system

You need to add the PATS module to the 2002 electrical system
You need a full time 12v wire
A key on 12v wire
A ground

The transceiver has 4 wires, a 12v and Ground, previously on separate wires in 2002 but the PATS module needs to power and ground transceiver in 2000 or it won't work
Then 2 data wires from transceiver to PATS module
Thats the 4 wires for transceiver

1 wire to instrument cluster for the THEFT light, same color wire on both years, dark blue/light green wire
It goes to pin 6 on clusters 16 pin connector

2 wires to vehicle Data network, pins 15 and 16 on PCM but also found on the OBD2 plug in the cab, these are spliced into the two wires, its a data network, so all wires need to stay connected, you are just adding 1 wire to each wire

There is no reason the 2000 PATS module needs to go above the glove box in a 2002 Ranger
You can locate it there, but it could also be located under dash on drivers side or ??, where ever there is room and easy wire access

 

[gkorgood]

Central security module is not part of PATS
You need to leave that connected, as is, its part of the Keyless Entry(Fobs) system

You need to add the PATS module to the 2002 electrical system
You need a full time 12v wire
A key on 12v wire
A ground

The transceiver has 4 wires, a 12v and Ground, previously on separate wires in 2002 but the PATS module needs to power and ground transceiver in 2000 or it won't work
Then 2 data wires from transceiver to PATS module
Thats the 4 wires for transceiver

1 wire to instrument cluster for the THEFT light, same color wire on both years, dark blue/light green wire
It goes to pin 6 on clusters 16 pin connector

2 wires to vehicle Data network, pins 15 and 16 on PCM but also found on the OBD2 plug in the cab, these are spliced into the two wires, its a data network, so all wires need to stay connected, you are just adding 1 wire to each wire

There is no reason the 2000 PATS module needs to go above the glove box in a 2002 Ranger
You can locate it there, but it could also be located under dash on drivers side or ??, where ever there is room and easy wire access

I've wired it up as described (finally, took all week of working on it when I got home from actual work). It still cranks but also still won't fire. The fuel pump relay still seems like it's not priming correctly, though instead of a rapid double click it sounds like 2-3 clicks with a slight pause between each, but not the 2-3 second prime I'm expecting. I did confirm expected operation of the theft light, it blinks every 2ish seconds with no key, turns off with the 2000 key, blinks rapidly and then gives code 13 with the 2002 key. Still confused as to why the computer doesn't want to let the engine turn on

 

[RonD]

11 Transceiver [transponder coil] not connected, or there is no power to it.
12 Transceiver internal fault.
13 No Key/no PATS key has been used to turn the ignition switch.
14 Incomplete key code received.
15 Invalid key code received.
16 CAN communications error.

code 13 means its not reading any PATS key at all
But no transceiver code so its hooked up OK

Try a different key even its the wrong key to see if you can get code 15


Fast flashing THEFT light means no fuel pump and no injectors so no start

 

[gkorgood]

11 Transceiver [transponder coil] not connected, or there is no power to it.
12 Transceiver internal fault.
13 No Key/no PATS key has been used to turn the ignition switch.
14 Incomplete key code received.
15 Invalid key code received.
16 CAN communications error.

code 13 means its not reading any PATS key at all
But no transceiver code so its hooked up OK

Try a different key even its the wrong key to see if you can get code 15


Fast flashing THEFT light means no fuel pump and no injectors so no start

PATS works fine with the 2000 key and cranks, but it still won't start. I just tried the 2002 key to verify pats would give a fault with it and that the theft light trouble codes worked, and they did.