Hey guys we need a hand. My son bought a 1994 Ranger Splash, 4.0, 5 speed two wheel drive. The prior owner really youtubed the poor truck to death. We are undoing some of his "repairs" but we are really stuck one one. The PO unhooked the wires from the fuse box for the fuel pump relay and I think the EEC.

We have have two wire bundles:
bundle one
yellow wire
black w/white
red
tan w/black
there was a relay taped to the bundle with 30,85, 86 and 87. With 87a in center.

bundle two
red
black w/ yellow
blue w/ orange
2 yellow w/green
there was a relay taped to the bundle with 30,85, 86 and 87. With 87a in center

Can someone provide a diagram or a guide to how they are wired. The stuff we have found just shows the wires going to the box but not where each wire goes on the relays. Not even sure the "bundles" are correct or if the PO was trying to bypass something.

The PO just cut the MAF harness and wired it in directly, we repaired that, and some other questionable things. We need these relays connected to move forward with other repairs.

Thanks in advance.

 

Welcome to the forum

On automotive relays 85 and 86 are the Coil connections, no polarity here, if 85 is 12v and 86 is Ground, then relay closed, or visa versa, but it needs BOTH 12v and Ground
30 is for the 12volt power for the Device(s) being powered, usually has 12v all the time, key on or off doesn't matter
87 is wired to the Device being powered, called The Load, 87 and 30 are connected when relay is ON/CLOSED

87a is not used often, it is connected to 30 when relay is OFF/OPEN, there are 4 pin relays(no 87a), and 5 pin relay(has 87a)

Auto makers reverse wiring for 30 and 87 all the time because it doesn't matter, when relay is ON they are connected so power flows thru relay, doesn't matter which one is full time 12v and which is the Load

EEC(PCM) Relay
yellow wire -- should be 12v IN full time from a 30amp fuse(#4 maybe), EEC(PCM) fuse, connects to 30
black w/white - full time Ground for coil 85
red - Load, sends 12v OUT to many devices when relay closes, 87
tan w/black - activation 12v, key on 86

EEC(PCM) Relay powers EEC(computer), fuel injectors, IAC Valve, MAF sensor(heater), a few solenoids, and fuel pump relay's coil


Fuel pump relay
red - 12v for the Coil, comes from EEC(PCM) Relay's red wire, 86
black w/ yellow - 12v full time from 20amp fuse, maybe #22, 30
blue w/ orange - Ground for coil, but...........Grounded by computer, computer turns fuel pump on and off using this Ground 85
2 yellow w/green - I show 2 dark green with yellow stripe here, Load, runs to computer(monitor) and thru inertia switch to power fuel pump, 87

Fuel pump relay is turned on/closed for 2 seconds only with key ON, then turns off, this is a safety feature, but it does this EACH TIME key is turned from off to on
Once engine is at 400rpm or higher computer closes fuel pump relay full time

Automotive relay layouts here: https://www.delcity.net/documents/au...ay_diagram.jsp

 

Outstanding and detailed. Thank you very much. We will wire this up and report back.

 

Well we wired it up as described and did get the fuel pump to cycle. Fuel pressure good. We would lose connection from time to time and the pump would turn off. Checked the relay wires figuring that was what we messed with so that was the place to start. Could not keep continued power to the fuse panel. After a bunch of teSt light time and frustration we found a bad 30amp fuse that would make intermittent contact. Replaced fuse and running.

Now we are down to a #1 misfire ocassionally and a TPS voltage problem we cannot shake. Look forward to a day with no CEL!

 

Good work

Thanks for the update

TPS is a variable resistor, like a volume control or light dimmer
Use a sewing needle to pierce wires for testing, while wires are connected
top wire should show 5volts, key on, from the computer
Center wire under 1volt with throttle closed, .69-.99v is spec
Open throttle and voltage should go up, steadily, no jumps of drops, at WOT(wide open) center wire should be at 4.5v to 4.9v

There is an Anti-diesel screw on the throttle linkage, looks like an idle screw but fuel injection can't use an idle screw, no Jets, so its an anti-diesel screw, lol.
Anyway people often goof up and try to use it as an idle screw, and this can then goof up the TPS setting because it opens throttle plate too far
If TPS voltage is too high when throttle is closed, turn this screw counter clockwise until TPS shows below 1 volt

Proper way to adjust this screw is to warm up the engine and let it idle, then unplug the IAC Valve
IAC Valve will close and engine RPMs should drop to 500, or engine may even stall, either is good it means throttle plate is closed enough, and NO VACUUM LEAKS
If RPMs don't drop then turn screw counter clockwise, if RPMs start to drop then keep turning until engine is barely running, 500RPMs, and its set
If turning the screw doesn't cause RPMs to drop then turn it back to where it was........and start looking for your Vacuum Leak, you have one

 

We have done the vacuum lines, checked and replaced the questionable ones. I suspected that the PO may have fiddle with the factory settings on the anti diesel screw as well, but it shows no tell tale signs of recent activity, no recent scratches, screwdriver skip marks or shiny clean spots. So we will avoid messing with it for now. We have the replacement TSP so we will plug and play it and see what we get, after the miles and PO magic we decided to replace it with new.

Updates as we run across problems or solutions.