Ranger Starting issue - Not the fuel pump

[Digbird1]

Hi, Just a follow up. Yesterday my mechanic came over and tested the current fuel pump. It wasn't priming. Then we installed a new pump and the same thing, It's not priming. So it doesn't seem to be the pump but getting power to the pump. We got it to start and run for about 10 seconds when the mechanic charged the pump, I'm not exactly sure what he did. But we know two things, It is not the fuel pump, It is the fuel pump not getting power. So I'm kind of back to the relay/distribution box. Which is I had been telling my mechanic based on feedback here. Probably time for a voltmeter and to check grounds. If you have any thoughts I'd appreciate the feedback. I'm going to post a new thread in the Ranger forum for older models. Thanks!

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[Digbird1]

Thanks again for the input. I swapped the fuel relay, the middle one with both other relays - no change, I checked the inertia switch and it hasn't been triggered. I also tried jumping the fuel relay. Could I have messed up something in the wiring or ground switching out the solenoid?

Hi, Just a follow up. Yesterday my mechanic came over and tested the current fuel pump. It wasn't priming. Then we installed a new pump and the same thing, It's not priming. So it doesn't seem to be the pump but getting power to the pump. We got it to start and run for about 10 seconds when the mechanic charged the pump, I'm not exactly sure what he did. But we know two things, It is not the fuel pump, It is the fuel pump not getting power. So I'm kind of back to the relay/distribution box. Which is I had been telling my mechanic based on feedback here. Probably time for a voltmeter and to check grounds. If you have any thoughts I'd appreciate the feedback. I'm going to post a new thread in the Ranger forum for older models. Thanks!

 

[airline tech]

My previously posted - Power Checks, need to be performed, to know which direction to go.
If you got to run for 10 seconds - confirms you have a bad connection or wire with broken strands or a short in the circuit - That possibly just burnt out the new pump.

This is a prime reason for wiring checks, hopefully the bed is still off for easy access to the complete wire run.
Just because the Fuel Inertia Switch is not tripped, does not truly tell you that it is letting power through it.
Think of a bad light switch, just because it is in the (ON) position, does not confirm the switch is good if the light is inoperative.
I would start at the switch 1st and use that as the fork in the road to know which direction to go.
Upstream or Downstream

It would not hurt to possibly doublecheck your connections on the Starter Relay, there is a Fuse Link on that circuit, but it feeds the Alternator.

 

[airline tech]

If the pump is still accessible disconnect the fuel outlet line and turn the key on, for a second and see if you can get fuel to flow. It may be a pressure issue, be aware it's going to dump fuel if it is working, so don't get your face near it.
If it pumps fuel, then replace the filter and the Fuel Press Regulator, for it running for 10 seconds after the new pump can also be (as you drained the fuel from the lines) a fuel pressure issue.

Check the vacuum line going to the Fuel Pressure Regulator and ensure its good and pull the vacuum line off of it and see if there is fuel inside it. If there is - Replace the FPR

This procedure will eliminate a pressure issue from the equation and confirm a power issue

 

[TJC]

What I find strange is that it starts and runs for 10 seconds. Maybe the mechanic ran power to the pump to make that happen, then pulled to power.

My dad's 1996 Ranger had a break in the ground line for the pump which kept it from running. When I could not narrow down the break in the ground I made another ground straight from the fuse panel box to a nearby fender bolt. A foot of 12 gauge wire did the trick. It ran like that for years.

It's been 20 years since I worked on it. But if my memory is correct, it was the fuel pump ground that failed. I found it by measuring voltage to body ground but no voltage from 12v pin to ground pin in the fuse box. I ran a temporary line to the fender bolt to test and the truck started up. I made the temporary wire permanent!

 

[Digbird1]

Thanks for the continued advice. I have access to the pump. Neither the old pump or the new pump are getting power. Like I said it did start right up and run for 10 seconds. We were able to verify gas flowing after I believe the Mechanic charged it with a battery pack. I checked the inertia switch and the switch is in the correct position. I still think it's something in the distribution box or a fuel pump relay connection or ground as that's the only fuel related thing I touched after it wouldn't crank. This is extremely frustrating as I paid for the mechanic to put in the new pump and we spent a couple hours to get access to the fuel pump when it doesn't seem to be the pump, but rather that the pump is not getting power. It was starting and running fine before. So any advice to resolve this will be greatly appreciated.

 

[airline tech]

As already posted, you need to meter (check for power at the switch) to determine where the power loss (which direction - Up or Down Stream) it is.

TJC also points out a valid point and that is the Ground for the pump, is right next to where you were at (Starter Relay) you possibly broke, disturbed that ground point.
This is assuming that G104 is the LF Fender and not the LR Fender, older manuals are not detailed enough for that.
I have a STRONG hunch that if I am following your steps of events, you replaced the starter relay for the no crank issue as well as swapped relays in the Relay Box - Correct?

With replacing the Starter Relay, proved no help and tapping the starter with a hammer, got the engine to crank

With swapping the relays, (a contact was pushed down for the FP Relay) - Now appears corrected - (not yet confirmed - corrected) other than contact is now up and locked into position.

At this point I would back track to the LF Fender and find all Ground Points that you see, pull the bolt and clean and re-install, inspect all wires on the ground wire harness at the lug.

With you jumping - Pins 30 & 87, the pump should have powered (on)
Since this appears to be a - No-Help, then.

You have a power loss between the relay box and the switch or between the switch and the pump.

or loss of ground for the pump.

Being that you were able to get a (10 second) pump run, tells me that the circuit is not completely broken, and you have a bad connection, and I am strongly feeling you have lost the ground. This would make the most sense as you were in the vicinity of the ground point when you replaced the starter relay.
As with TJC posts about the Ground, and your post of the starter relay, this is the most logical spot to check and would explain why - all of a sudden you have a non-running pump when the original issue was starter related.

Other than that quick check of the Ground, you MUST do a Wiring Check, this requires a meter to properly check the circuit.
To test the Ground from the FP connector, you disconnect the connector.
Red Meter Lead - To the Ground Wire (on the connector)
Black Meter Lead - To a good / clean body ground (frame) you should see a (Resistance) of under 3 Ohms (average)if higher than 3 ohms, then the other end of the Ground Wire is not making good contact (G104)

 

[TJC]

I also saw the same problem in an earlier early to mid 90's Ranger that my son in law owned. His was intermittent until it finally failed. I honestly suspect it is a corrosion problem that is common in those early Rangers.

He sold it before I could visit him to diagnose it. But it was the fuel pump circuit. I told him what I did to my Dad's Ranger to repair it, but he is electrically illiterate... and a tad impatient.

I used something like this to make a jumper from the ground from the top of the fuse box location. It was all I had in my emergency tool bag on a Sunday afternoon 300 miles from home that get the job done. That and a female crimp spade connector and a crimp eyelet connector under the fender bolt.

I kept things like this in my emergency tool bag in case of a breakdown on a road trip. It is funny that I had never used any of that stuff prior to this repair or after!

I don't recall the ground location as has been too long to be sure.

I remember having to bend / form it to bring it up enough to connect my homemade ground test wire. I was visiting my dad and didn't have time to find the break in the ground wire so I left the wire on the fender bolt and put the fuse cover back on it. He drove it for 5 years like that.

 

[Jason B]

Isn't there more logic to this? Maybe not this way on this model, but
I remember on other vehicles that when the key is turned to 'on' the pump primes, i.e. runs for a few seconds, then goes off. When the key is turned to 'start', the pump will only be powered if a signal is received from either from the crank position sensor, cam position sensor, or some kind of timing sensor. It's been a long time so I can't remember what it was, but the ECU had to see the engine rotating before re-engaging the fuel pump.
Something to think about, I guess.

 

[TJC]

In my father's case the pump never primed. We had power at the relay during the 3 second prime, but the pump never ran. I completed the circuit by bypassing the pump ground and the pump energized.

My diagnostic approach was to test the circuit before pulling the bed of the truck to access the pump wiring at that end. When the ground socket in the fuse box was tested, I had no continuity between the it and the battery ground. So I knew the ground wire was broken.

Conceptually it is a very simple circuit. Power from battery to pump, ground from pump back to battery. If either is open the pump will not run. All those sensors you mentioned are possible control points to turn the power on to the circuit. And I am not even sure if they are actually used to control the pump circuit. All you really need is a pressure regulator contact switch that powers the pump relay.

An even simpler approach is to run the pump continuously, and have a bypass regulator that bleeds the excess pressure back into the tank. That pressure regulator is part of the pump assembly in my 2005 Ranger and is what recently failed. The fuel filter has a return port built into it going back to the fuel pump assembly in the tank.

I looked for the open but ran out of time and left the patch wire to ground on the truck. It ran with that red wire (I did not have a black wire in my emergency tool bag) coming from the top of the relay/fuse panel to the nearest fender bolt until my father died 5 years later and I purchased the truck from my mother to donate it to his care giver, who put it to good use on her farm. She drove it until she could no longer live alone on the farm 10 years later.

It was a patch for sure, but it proved to be reliable. I am only recommending it as a test to determine where the issue is. The proper repair route is to correct the open in the ground wiring circuit.

I'm a proud "Son of the South", and at times I revert to my "redneck" upbringing!

"GETTER DONE BOY!"

 

[airline tech]

Isn't there more logic to this? Maybe not this way on this model, but
I remember on other vehicles that when the key is turned to 'on' the pump primes, i.e. runs for a few seconds, then goes off. When the key is turned to 'start', the pump will only be powered if a signal is received from either from the crank position sensor, cam position sensor, or some kind of timing sensor. It's been a long time so I can't remember what it was, but the ECU had to see the engine rotating before re-engaging the fuel pump.
Something to think about, I guess.

YES - and this is the main reason - I am pushing for a Wiring (Voltage Check) which his mechanic is refusing to do - I guess

This is also the reason - I had him - Jumper the Relay as this by-passes that relay.

Power to that relay (FP) comes off of the EEC Power Relay and the Ground comes from the EEC seeing an ignition signal input and crankshaft rotation.

So, it is still possible for an EEC relay issue or Crank Position Sensor issue, dropping the Ground off of the FP relay.
With a jumper at the FP relay, you take 1/2 of the T-Shoot out of the equation, as you are suppling a direct uninterrupted power feed to the Fuel Pump, if all the wiring Power & Ground are good between the 2, that pump should be running.

With the relay installed the (normal) operation for control comes from the EEC grounding the FP relay and the (ONLY) way to know exactly what is happening here is to get a meter and know what to check for power.
I have provided a Step-by-Step procedure to isolate the issue and the mechanic has ignored my suggestions and thus has spent the time and wasted the OP's money on replacing a FP that did not need replacing, if he had only used a meter to check for power at the Fuel Inertia Switch (5-Minutes) or the test procedure at the Relay box test port, this could have been avoided.

I get it, some mechanics are just parts changers, and refuse to accept the fact that the issue can be wiring related mainly for the sheer fact that they do not know how to use a meter or are too scared to use one. I have been a mechanic both Automotive & Aircraft for almost 40 years, I have seen both types of mechanics. A mechanic in today's age of cars, you cannot be a parts changer, you have to learn how to use a meter (at least basic usage) do you have power & ground to the inoperative part? If yes - replace part, if no - diagnose WHY.

Another tool that would help (for this thread) is to hook up a scan tool and ensure you are getting Crank and Cam position sensor pulses while cranking the engine over. (with the FP relay installed) as with the FP relay jumped you take this need for input out of the equation for that fuel pump to run.

 

[Digbird1]

In my father's case the pump never primed. We had power at the relay during the 3 second prime, but the pump never ran. I completed the circuit by bypassing the pump ground and the pump energized.

My diagnostic approach was to test the circuit before pulling the bed of the truck to access the pump wiring at that end. When the ground socket in the fuse box was tested, I had no continuity between the it and the battery ground. So I knew the ground wire was broken.

Conceptually it is a very simple circuit. Power from battery to pump, ground from pump back to battery. If either is open the pump will not run. All those sensors you mentioned are possible control points to turn the power on to the circuit. And I am not even sure if they are actually used to control the pump circuit. All you really need is a pressure regulator contact switch that powers the pump relay.

An even simpler approach is to run the pump continuously, and have a bypass regulator that bleeds the excess pressure back into the tank. That pressure regulator is part of the pump assembly in my 2005 Ranger and is what recently failed. The fuel filter has a return port built into it going back to the fuel pump assembly in the tank.

I looked for the open but ran out of time and left the patch wire to ground on the truck. It ran with that red wire (I did not have a black wire in my emergency tool bag) coming from the top of the relay/fuse panel to the nearest fender bolt until my father died 5 years later and I purchased the truck from my mother to donate it to his care giver, who put it to good use on her farm. She drove it until she could no longer live alone on the farm 10 years later.

It was a patch for sure, but it proved to be reliable. I am only recommending it as a test to determine where the issue is. The proper repair route is to correct the open in the ground wiring circuit.

I'm a proud "Son of the South", and at times I revert to my "redneck" upbringing!

"GETTER DONE BOY!"

When I swapped out the starter relay I remember there's two ground wires. I wonder if I may caused this issue myself by screwing up the ground. I don't understand what is meant by making a jumper to jumper the ground from the top of the fuel box. After installing the new pump my mechanic sort of ate his words and is bringing over a meter, a voltmeter I think. Thanks again for the help!!

 

[TJC]

The "Jumper" is simply a piece of 12-14 gauge wire with a female spade connector on one end to connect to the male spade connector I added to the ground (2nd picture - copper piece), the other end of the jumper wire had a eyelet that was placed beneath the fender bolt to complete the ground circuit.

The jumper wire was then connected to this male spade contact that was placed on the ground side of the relay just like it is on the fuse below. I had to form it to get it up and around the relay.

It wasn't the relay coil ground. It was the pump ground.
(I am working from a 20 year old memory here. So find the pump ground and go from there). This was all done at the fuse box located on the drivers side fender well. The jumper wire was about 1 foot long.

All this did was prove that the pump ground was the problem. The proper fix is to repair the ground connection. This jumper wire simply bypassed the faulty ground wire.

This may or may not be your problem, but I have seen 2 1992-1996 2.3L Rangers with this problem. I only had the opportunity to resolve one of them.

 

[airline tech]

When I swapped out the starter relay I remember there's two ground wires. I wonder if I may caused this issue myself by screwing up the ground. I don't understand what is meant by making a jumper to jumper the ground from the top of the fuel box. After installing the new pump my mechanic sort of ate his words and is bringing over a meter, a voltmeter I think. Thanks again for the help!!

I believe he used the EEC Test port - at the relay box and provided a ground for the FP relay, as I posted above, this is not the ground for the pump itself, this is only forcing a ground to the FP coil side of the relay, which you by-passed with the jumper 30-87.
The test port only provides a way to by-pass the relay (control ground) from the EEC and would be used to confirm a bad output from the EEC (control) and or wiring to the FP relay, as with key on and a forced ground - the FP relay should close and power the pump.
You have already done this by jumping the pins 30 & 87 and by-passed the need for this step

 

[airline tech]

Some models have an extra test port, specific to the Fuel Pump, and this is most likely where TJC had tapped into, the wiring diagram I can see, for the 94 does not have or show that extra test port, it only shows the EEC test port, which is the grounding of the FP relay.
However, you have to keep in mind that wiring diagrams from an older era before computers do not always get properly uploaded to a computer base and may or may not show exact detail for a specific year.

So, if what TJC is true, there is an extra unseen test port that provides a way to force and or test the ground side of the Pump. Not seen so far in any wiring diagram for this 94 Ranger - so far

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