Ranger Starting issue - Fuel Pump?

[TJC]

Maybe the G103 wire was damaged? Is that the ground for the fuel pump?

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[Digbird1]

Ok, here is a better detail, reminder I said that older manuals are sometimes not imported onto databases correctly, as I found a discrepancy in them already.
I am pointing out the Ground for the Fuel Pump, I believe the following is the correct G103 Point.
Note other diagrams show G104 as the pump ground.

Another clue that this Ground is the issue, does your Fuel Gauge Work?
The Pump & Gauge have different power inputs but share that ground point.
This is a good point of T/Shoot (knowledge)

I want to draw attention to its location and the location of the Starter Relay (You Replaced)
Its right next to it:

Check the G103 for security and ensure it has a solid clean connection and all wires to that lug are intact.

With all you have done, and the truck was running prior to you, replacing the starter relay, I HIGHLY suspect your whole issue is here.

About the same diagram, except this one highlights (1) thing and that is the Fuse Link,
Note how it is part of the Starter Relay Wiring, if this was strained or pulled during install, it is possible you broke the wire, now this link feeds the Alternator and is a protection circuit.
You have a large gauge wire - dropping down to a lower gauge wire, its intent is to burn the lower gauge wire in half to break the circuit (a fuse in a wire) AKA Fusable Link

Check that section of wire, you should feel a soft area inside the insulation where it has melted, if it has - you can also find the spot where the gauge changes (gets larger) - grab that spot and the other end of the wire - grab it and give it a slight tug, if the link is melted you will be able to stretch the wire (insulation)

I do not think this is your issue, but a good idea to check it, being you were touching that wire when the relay was replaced.

Now let's get a meter and focus on the Fuel Pump Ground (1st)
If the above G103 appears intact and a good clean connection.

Key Off:

At the Fuel Pump Connector (4 -Wires)

Pinout as follows:
Black Wire = Fuel Pump Ground
Black / Yellow Wire = Fuel Sender Ground (Gauge)

Meter (Ohms) Scale
Red Lead - To Black Wire ---Black Lead to a Good / CLEAN Body Ground (Frame)
Repeat the same for the Black / Yellow Wire

You should see a reading of around 3 to 5 ohms
This is testing the resistance of the ground wire from G103 back to the Fuel Pump Connector.

If this is high resistance, the pump or gauge will not operate. you most likely have a Mega Ohms reading here (if I am correct)

To correct the issue, closely check the G103 (ground point) and the wires going into the lug.
If no issues are found with that G103 then you have the option of spending the time to locate the broken ground or just run a new set of ground wires to the G103 location or a new location altogether (add into an existing) ground along the frame or make a new one.
So, cut and splice in a (NEW) Ground

That covers the Pump Ground

Let's move on to the Power Side: Which we have already covered some

When you cycle the key to on - The Pump Primes for (2 seconds) if the EEC does not see an ignition input it shuts the pump off.
So, testing for power at the pump can be misleading if you do not know this (operation) note.

So, how does the EEC turn off the pump?
It does this by removing the ground from the (coil side) of the FP Relay
The EEC is controlling this:

So how can we check for power (if it shuts off in 2 seconds) Commanded

You can have your meter hook up at the FP Connector and every time you cycle the key you will see 12-volt power at the connector for 2 seconds.

or

Use Step 1 OR Step 2 - For T/Shoot Power

We can by-pass the EEC control and force a constant 12-volts to the pump via:

Step 1: Leave the FP Relay installed and go to the EEC Test Connector, Jumper the FP Test Port to a good body ground
Turn Ign key to (ON) and then test for power anywhere on the Fuel Pump Circuit, you now have forced a ground to be applied to the Coil Side of the FP Relay and should have constant 12-volts being applied to the pump.

Step 2: You have already done, and that is jumper the FP Relay (Removed) (Top & Bottom) pins
This applies direct 12-Volt power to the pump (when key is on)

In step 1 - Tests the whole Fuel Pump circuit, except the EEC Control for Coil Ground as you are forcing the ground from the EEC

If step 1 - gets the pump to run, then you have an issue with the EEC or the ground for the relay coil
If step 1 - is no help, then you have a power or ground issue (pump control)

In step 2, you are by-passing the relay completely and are jumping the power feed from one side of the relay to the other (completing the circuit) that the relay controls.

Ok, here is the complete diagram:

Let's start with are we getting power at the Fuel Pump:

Note: set up the power feed described above (using step 1 or 2) and Turn Ignition Key to (ON)


At the FP Connector
Pinouts as Follows:

Note: Voltage readings are dependent upon what your current battery voltage is (?)
Normally this is around 12 volts, so do a test of (CURRENT) battery voltage and apply that reading to all (test result) readings below.

Pink / Black Wire = Fuel Pump Power
Black Wire = Fuel Pump Ground

Meter on Volt DC Scale
Red Lead - To Pink / Black
Black Lead - To Black Wire
and then
Black Lead to - Body Ground (Frame)
You should be reading 12 volts on both test points
If you have a better reading when going to body ground, then you have bad ground circuit.

The reason for checking both points is we need to separate the ground points to ensure we have a good ground circuit, when you go straight to body ground you are by-passing the ground wire run to (G-103)

Repeat this test using the Fuel Sender Gauge (Wires)

Note: The fuel sender (gauge) I believe is a 5-Volt circuit so you will most likely see 5-volts in this test:

Pin Out:
Yellow / White = Fuel Sender (Gauge) Power
Black / Yellow = Fuel Sender (Gauge) Ground

Same power test as above for the pump power (only use these) wires

If I am correct, you should see 5-Volts and the same matching voltage on both tests (wire and body grounds)
Same as above if the body ground provides a better (higher) voltage reading then you have a ground circuit issue.

Note: here as I want to point out that since this is a lower voltage, it's easier for power to get to ground, so this is a shared ground circuit with the pump power, so you could possibly see a good test result on this (as far as the wire ground / body ground) separation check.

Ok, If we do not have power at the Pump Connector and our Pump / Gage grounds are good, then we have a power issue confirmed.

It is a good T/Shoot Practice to split your test circuit in half, to help isolate which side of the circuit you need to diagnose.

A perfect spot is the Fuel Inertia Switch:

With the (Step 1 or 2) still in play and the Ign Key (ON)

I suspect that it has a connector, on it - If not you will need to back probe it via:
T-Pin (Wifes sewing kit) or a paper clip, slide it carefully down the side of the wire to hot the contact pin:

Pinout:
Dark Green / Yellow = Switch Input

Meter Set (Voltage DC)
Red Lead to - Dark Green / Yellow
Black Lead - To Body Ground

You should have 12-Volts
If yes, then the switch is bad or wire feed between the switch and the pump is bad.
Note there are 2ea inline connectors between the switch and the pump
I can dig for locations (if needed)

To test the switch (isolate) switch vs wiring (between the switch) and pump
Key (OFF) connect the connector to the switch and back probe the other wire:
Pink / Black - Key (ON) and check for voltage on this side of the switch same as above for the Dark Green / Yellow wire

If you have power on one side and not the other - It's the Switch

If no, power on the Dark Green / Yellow then we need to move farther upstream of the switch

So - Undo Step 1 or Step 2, Turn key (OFF)

Pull the FP Relay out (if using step 1)

Key (ON) and with meter in Volts DC
Ref the Diagram Above:

Note: Since I am not sure (100%) which Terminals are what (Location)
I do know that the (2) vertical contacts are 30 & 87 (the center one is 87a)
The Horizontal ones are Contacts 85 & 86

But with that in mind should be:
Pin 87 = Top
Pin 30 = Bottom
Pin 85 = Right
Pin 86 = Left

The vertical & horizontal may be opposite sides of each other (so swap them if needed)

The main point is with Key (ON) you should be getting power to (2) contact pins
Pins: 30 & 86

Pin 30 = Always Powered
Pin 86 = Powers with Key (ON) and the EEC Relay Closes (Switched Power)

With meter set to Volts DC:
Red Lead to Pin 30
Black Lead to (Neg) Batt Terminal or Body Ground

Repeat for Pin 86:

You should be getting 12-Volts, note if no voltage swap to the opposite side (vert or Harz) in case my Top/Bottom and Left/Right are backwards.
On BOTH Contacts - 30 & 86

If no power on pin 30 - the issue is in the relay box or fuse
if no power on pin 86 - the issue in with the EEC/PCM power relay or wiring
This is where is gets deep into a T/Shoot as we do not know if the Wiring/ PCM Power Relay / or the EEC itself has fried.
So, we need to do a more detailed T/Shoot - If this is the case as there are deeper steps to take for this.

If you have power on both pins 30 & 86,
Then you have an issue with the FP Relay itself or relay box
To T/Shoot this, we need to disconnect the battery, the EEC Connector and the Fuel Inertia Switch and use the meter (ohms) scale and resistance check the wires
For the wire runs for Pins 87 & 85 and pull apart the Relay box and check for broken wire feeds coming from the FP Pump relay contacts - with a close inspection of the pin that was pushed down

There you have it - A HIGHLY Detailed - T/Shoot Guideline.
This is the steps I would take to tackle this issue

As I said, with you getting a temporary run (10-Seconds) and you working in the area of the Pump Ground, I have a feeling you just have a bad ground connection.
I would also say that it is possible that you broke the Fuse Link at the Starter Relay, and that may be playing into this - throwing a kink in the T/Shoot process.
But my strong hunch is the Ground Point (G103)

Hopefully, the mechanic can and will use this T/Shoot Guideline, as if you get it towed to a shop these are the steps they will follow as this is the only way to find the issue you have.
It may be a good idea as you mentioned you have a battery charger, would be to get the battery fully charged up, to allow the key to be on and still have enough voltage to crank the engine over, plus it gives better test results (more precise)

One small detail EDIT:
Note in the wiring diagram C141 , it may be possibly you knocked this connector lose when messing with the starter or leaning over the fender, back up to the 2nd picture for its location.
This connector has FP Power feeding the Switch & Pump (by the diagram) this would be a quick check, disconnect and reconnect thing, and incorporate that connector if needed in checking for power - Just note the (wire colors) for testing

So I turned the key on and the fuel gauge moves a little and shows 1/4 tank, which is correct. But the gauge is at a bit above 1/4 tank with the key off. All of the gauges move whith the key on. I'm not sure if that points to the ground or not.

 

[TomSim]

Why do you think it's the starter when it cranks over and has started. The problem for sure is that the engine is not getting gas. That's one thing that we know for sure. How can the starter affect the engine not getting fuel?

you said that once you hit the starter with a hammer it started??

 

[airline tech]

YES, that is the Ground for the Fuel Pump and is a shared ground with the Fuel Gauge

Plus, I wanted to add, that I have kept it simple and basic for the T/Shoot and only using a basic meter.

There are more advanced tools available that most shops have to make the job easier.
Sush as the one I have, it's an expensive tool but I love it, its versatile and I do not have to rely on jumpers for power etc as I can apply Power & Ground with the Probe works great for testing circuits. It also includes a Tone Generator, so I can send a signal down a harness run and locate where the circuit loss is at.
This is what I have and if you can find a mechanic that has this or similar, it would make the job even easier.
This is the same as a Multi-Meter except it has a lot more functionality hence the $380.00 price tag for it.

 

[Jason B]

You need a new mechanic. DO NOT let him permanently bypass the relay circuits by running a new wire to the FP. If he can't follow the instructions suggested by TJC and airline tech, he's going to cause more harm than good. It's possible for him to cause the pump to be always running when the key is in the 'On' position. The danger there is if you were to get in an accident, the pump would continuously run if the engine were not running, causing a potential fire hazard. Even if you were just working on the truck with the key on for the radio, the pump would always run, possibly causing damage.

 

[airline tech]

Sounds like the starter to me, not the fuel pump

Starter (YES) for the no crank issue, but right now that appears to be on stand-by (working) at the moment - but somehow either by Self-Induced or it just happened (both) issues popped up at the same time, the truck is cranking but not starting and is being reported as Fuel Pump not running, so we are trying to pinpoint and isolate the issue (pump or command for the pump) which the EEC is in control of. Hence the power and ground checks that has not been done (yet)

 

[airline tech]

Maybe the G103 wire was damaged? Is that the ground for the fuel pump?

Yes, G103 is the Ground for the Fuel Pump, Check this for security, just in case you moved or damaged that wire, ensure its not pinched under the Starter Relay. I am focused on this for the sole reason, this would explain why all of a sudden, the pump is not running just after you were in this area. (a high possibility) of a damaged wire or lose ground point.

 

[airline tech]

To be a little more precise, Near G103, if you follow the harness down from that Ground Point, I am focused on a Splice (S105) - you should see a spot where 6 ea wires are bundled together with a single wire running over to the Ground Bolt (This is where numerous ground wires run together) (Splice)
They are:
Fuel Gauge, Instrument Cluster, Brake Fluid Level Switch, Left Headlight, Engine Compartment Light, AC Clutch (coil) and AC Clutch (Diode)
If you are having a Ground Issue, the Splice would be the area that is high probability of being damaged, the Fuel Pump and the Left Headlight are the highest power draw, and they would be the 2 items most affected (in not working correctly)
So, I would try this, turn on the headlights and shake the ground wire near G103, see if you can get the headlight to flicker and or the FP to run, or produce a power jump at the FP connector.

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