PLEASE HELP!!! no fuel pump relay or injector pulse

[tofuman]

Hey everyone! I really need urgent help but didn't post in the urgent help section because I already called it a night and but really stuck and gonna go back tomorrow! So i bought an 88 ranger 2.9 v6 4x4 with the duel tank option for a good price because it jus needed a fuel pump... Well they were wrong the first thinkG i did was replaced the fuel lines they had cut and eliminated the middle tank to simplify the system, save weight and this was jus gonna be my daily commuter. So then I checked if the fuel pumps were working so checked relay then inertia switch and noticed the botton loose so i jus bypassed it but still no fuel relau but they would work wen I put ground on the, iirc orange wire on the fuel pump relay and both the inline pump and in tank pump turned on and sounded strong! But the fuel pump relay will not work on its own, so I went to my local u pull it junkyard and got two OEM fuel pump relays and eec realys and also got my hands on an exact number matching ecu from a bronco 2 with 4x4 and manual and I also read a lot on here and learned that map sensor has caused no injector. Pulse so I snagged an extra as well, my ignition switch was held together with a zip tie so I got one to. So I started with replacing the fuel pump relay and nope! And this point my dash is showing the 4x4 light, and oil light but no cel and no eec relay click so then I changed the switch and now the 4x4 light went away and now eec clicks and the check oil light turnes on while cranking but.... Fuel pump relay still not working on its own and no injector pulse so tried replacing the computer and STILL NOTHING but noticed both computer got hot and I was cranking and had the car on and what not so I checked all grounds and all seemed fine which were the 3 on the battery - terminal and the ecu one so pretty that has something to do with something. So I come to u ranger gurus to please guide to what to check next

 

[RonD]

Pull out fuel pump relay.
Use test light or volt meter
key off
There should be only 1 slot in the fuel pump relay Socket that has 12volts, that's the Fuel pump power, it has power 24/7(all the time).
If no slot has 12volts then Fuse or fusible link is blown.
If you have an engine Power Box then look at fuse #1 30amp, if no Power Box then look at starter relay, one of the larger posts will have the Battery positive cable, that is where all the fusible links will be, follow each one and find the broken one(broken wire)

If you have 12volts in the socket then turn on key.
You will now have a 2nd 12v slot find it, that is power for the relay from the EEC relay, if no 2nd 12v slot then wire is broken to EEC relay, red wire.

If you have 2nd 12v slot then put Relay back in place, then find the OBD 1 connector, usually by firewall drivers side, but can be on passenger side as well.

Picture of it here: http://www.therangerstation.com/tech_library/OBD_I.shtml

2nd drawing down
Fuel pump slot is labelled.
That is the ground for the fuel pump Relay, it is spliced into computers fuel pump activation pin.
With key on put a wire in that slot and then Ground the other end of the wire, fuel pump relay should click and fuel pumps should start.
If not then wire at fuel pump relay is broken, light blue/orange stripe wire

 

[tofuman]

Thank u so much for the great detailed info its been raining all morning so jus waiting for it to ease before i get crackin and willpost back with updates

 

[tofuman]

So sorry for the late response! Weather and work and not been on my side but I'm here now and I grounded the pin on the obd1 connector and yes fuel pump engages, any suggestions on what to check next

 

[tofuman]

I tried starting with the fuel pump engaged with thr wire jumped again and still nothing tried both Computers again and nothing still no injector spark and I'm sure it has to do with the fuel pump not being able to work on its own

 

[RonD]

Well the computer should ground the fuel pump relay for 2 seconds when key is turned on, that is the normal "power up" for the computer.

On an '88 with TFI ignition the computer will not start the fuel injectors until it gets a "pulse" from the TFI module, basically a timing signal for when to open injectors, injectors need to be timed like spark plugs.

Look here, toward the bottom: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

The PIP(Profile Ignition Pickup) is the "pulse" the TFI module sends TO the computer(EEC), this same pulse is used by TFI module for spark timing.
This pulse comes from the sensor inside the distributor.
SPOUT is the signal FROM the computer that controls spark advance.

If there is no spark or injectors then either sensor in distributor is bad or TFI module is.
Could also be bad wires, but that would usually on effect one or the other.
Make sure you have 12volts at TFI and coil when key is on

But regardless of the "pulse", the fuel pump should still come on for 2 seconds with the key being turned on, computer won't turn it on again until engine RPMs(pulses) are above 500, so after engine starts

On distributorless engines a Crank Position(CKP) sensor is used for the "PIP" to time spark and fuel injectors.

 

[tofuman]

Sorry for not replying in awhile, haven't been able to work on the truck, but got around to it today and now i jave spark so i checked continuity in the pip wire from the icm and it checked out so also started checking a couple of other wires and they seemed good so went to by a new ecu but still no injector pulse or fuel pump relay

 

[tofuman]

Also all 3 computers get really hot after several minutes of cranking and diagnosing do I know for sure somethings wrong but don't know were else to check

 

[RonD]

Here is the pin out and voltages for pre-'95 computers: http://www.auto-diagnostics.info/ford_eec_iv

Only real heat the computer would put out would be from the Power Supplies when it lowers 12volts down to 5v for sensors/controls and chips on the board, those Power Supplies are what you see around the edges of the circuit board, the Black units, and they are using the chassis as a heat sink to bleed off extra heat.
So reads like shorted wire or wires would be the issue

 

[tofuman]

Awesome!! helps ALOT thank u so much for all ur Great insight and experiences! I will do further research and inspection of the harness then no that I have the pin out