No fuel to Fuel Rail.

[gaz]

Hello,

Swapped my BII's rebuilt 2.9L into the Ranger. After rellocating my fuel tank to be hind the axle in my 87 Ranger will start on starter fluid but gets no fuel to the rail.

*I have verified that both pumps work with 12v applied
*I extended the fuel and return lines from the original tank location to the new tanks location.
*I extended to pump power, ground, sender and ground wires to the new location.
*the connector "y" where the pump power splices was dirty, especially the supply side but now thouroughly cleaned.

With the starter disabled and the pumps disconnected, I get 12v to the "y" splice very briefly with the key to the run position. Same thing happens when I go to the start position, 12v briefly then nothing. Is this normal? Is there a reason that the pump supply power stops? Is it because the pumps aren't wired in?

 

[RonD]

You should only get 12v on fuel pump wires for 2 seconds with key on, that's normal, its a safety feature

After engine is above 400rpms fuel pump will get full time 12volts(well 13.5volts from alternator, lol)

For test you can manually active the Fuel Pump relay usuing a jumper wire on the OBD1 connector in engine bay

Look here: https://www.therangerstation.com/tech_library/OBD_I.shtml

Fuel pump slot in OBD connector is labelled in 2nd drawing
GROUND that slot with a jumper wire and fuel pump will come on when key is on


As for no fuel pressure
There are 2 fuel lines in the engine bay
IN from the fuel filter goes directly into the Fuel rail
OUT to back to gas tank is connected to FPR(fuel pressure regulator), looks like small can

They should have different connectors, but................

 

[gaz]

RonD:

Are you saying that if I jump a wire as directed on the referenced OBD1 test port, as instructed, it will simulate the engine running so that I can continue to verify power supply voltages beyond the safety feature?

The wires I have going to the gas tank (LP pump) are orange, pink/black stripes, yellow/stripe and black. My wire manual shows:

pink/stripe as pump power
orange as tank level sensor
black as gnd
yellow/stripe as gnd

The wierd thing is the wire connector to the tank has the following wire layout and is how it's wired:

Orange to pump gnd
Pink to pump power
Yellow to sensor/sendor
Black to chassis

 

[gaz]

Things may be looking good; the fuel pump splice connection is in bad shape. On the make side, it can slide out on it's own. I am zip tieng it in and a dab O electrical tape for the good measure.

Once I get it primed and back together I will report.

 

[RonD]

Yes, the jumper wire grounds the FP Relay full time by passing the computers ground, so simulates "engine running" status

The orange is the Ground
The Yellow is to/from the fuel gauge

so this should be the layout
Orange to pump gnd
Pink to pump power
Yellow to sensor/sendor
Black to chassis(sender ground)

Pink comes from inertia switch <<< and should be spliced to high pressure pump 12v wire
Yellow comes from instrument cluster

 

[gaz]

Does the key need to be in the run position for this to work?

 

[gaz]

The engine bay fuel pump splice was not the only problem. The manual says to start at the problem and work my way back, I did this. I'm going to start at the relay and work my way to the pumps.

I have attempted to utilize this engine bay OB1 bypass to charge my fuel rail. Unfortunately, it did not help the outcome.

What is happening is peculiar. I get good readings at each step of the power path until I plug in the load, the pump. Then I get nothing. The pump works normal with 12v, each section of wiring, each connector is clean .

I give the pump or pump assembly 12v it spins. I am going to work from the battery.

 

[adsm08]

Does the key need to be in the run position for this to work?

Yes, because the key switches the powers to the circuit. The wire at the EEC test connector only grounds the fuel pump relay.

 

[gaz]

adsm08,

Thank you. I know it makes sense, I had to ask because it didn't change anything ..(
I am going to go through all my grounds and if necessary, buff-up the the fuel power wire system until it works. I had a Neon, Dodge used too small a wire for the ground runs to the fuel pumps. It is a known issue for those cars and replacing the stock wiring with one size up, fresh O² free wiring cured it on the spot. I can only hope it helps.

While troubleshooting this I have found a goofy grounding issue with my doors. When the doors are open, the power to the fuel system reads 0.5V. This is unsettlingly, though the ignition buzzer connection in the glove box unplugged settles both the anoying buzzer and the unsolicited power on the fuel system.

I am really excited about putting some miles on the ole Ranger, I sure hope I can figure this out this weekend

 

[snoranger]

What is happening is peculiar. I get good readings at each step of the power path until I plug in the load, the pump.

You’ve got a bad connection or corroded wire. It’s not allowing the circuit to carry the required amps.

 

[gaz]

While troubleshooting the fuel electrical system, I was lead to an intermittent fault in the EEC Power Relay (the Brown relay). the power supply wire from EEC had been pushed back about 1-3 mm and was only connecting on certain angles and not while mounted on the fender well. I had unmounted the relay to test the circuits and while doing so with the key in the run, I lost my grip and the angle moved. That was when I heard the relay actuate and subsequently actuate the fuel relay too.

I am replacing the female side of the relay this afternoon. I hope that I haven't banged up too many of the other connectors ..(

 

[gaz]

To get to the next step, I built a stand alone fuel power circuit. I took ignition power from the low current side of the engine bay Fuel relay (the green relay), fused (5amp) to a manual toggle switch in the cab, controlling a stand alone relay, load side has fused (10amp) battery power.

This circuit works great, both pumps spool up with the key in the run position and the engine does start in the start position. The rail is pressurized with no leaks.

There are a couple issues:

-the first start requires starter fluid.
-it stumbles a little and will stall the first 2-3 starts.
-once warmed up, I have a higher than normal idle.

I figure I have a vacuum leak, either an injector O-ring, T/B of upper intake gasket fail.

I am replacing the injector O-rings, the T/B and upper intake gaskets.

 

[RonD]

All gasoline engines need to be CHOKED on cold start, with fuel injection the computer must Choke the cold engine, since there are no Jets to suck extra fuel from, which is what choke plate did on a carb.

So computer needs to know when engine is cold, this is why the ECT(engine coolant temp) sensor was added with fuel injection
So check ECT sensors wires, its a 5volt sensor like most sensors and it should set a code if its not working but............
If ECT sensor is reporting engine is at 150degF when its actually at 60deg(outside temp) then NO CHOKE on start up, computer thinks its just a warm engine restart, and also no code

You will probably need a 20amp fuse for fuel pumps power, 10amp may blow

 

[gaz]

RonD,

I was unsure about the current required for the pumps. I measured 6 amps but built the circuit for 30amp and started with the 10 amp fuse to see how it handles it.

I will check the codes and take a look at the sensor and it's wires. I am seeing normal temperature gauge activity in the dash cluster. It is still idling a little high so I still suspect a vacuum leak. This may also be due to the last engine bay connector, it goes to the air box and I'm not sure what sensor it runs but my airbox is buried in my shed. I will install it as done as I find it in there. Just bought a light for the shed, perhaps that will seal the deal.

I am dealing with a small exhaust leak. At first it sounded like the driver's side collector to header. After removing the collector back, it looks like it is the slip-joint in the middle of the 2 piece "Y" collector. This joint has always required a little extra attention but this time I used 1 size too large of slip-joint clamp. I replaced the clamp but I am still getting a little leak. I will need to fiddle with this some more after 1) I get start up condition, 2) idle in check.

I did not know that the ECT sensor performed this task. That is really interesting and I appreciate you sharing as that fault is much more desirable than pulling the T/B, upper intake and rail

 

[RonD]

Yes, average 6amp draw would be about right for the fuel pumps, but electric motors will have a spike in amps on startup then once up to speed a steady lower amp draw