Fuel pump clicks, but doesn't whirr

Went to start my truck to get it out of the way for the moving truck yesterday, and it wouldn't start.

I think its the fuel pump. When the key is turned to on you can hear a click but it doesn't make the typical whirring sound.

Anything else it could possibly be other than the pump? How do I go about diagnosing this as a pump problem for sure?

Thanks.

The click is probably the relay that's supposed to send power to the pump. I'd first measure the voltage at the pump, and see if the power is getting there. If so, then the pump has probably failed. If not, then your problem is in the wires, connectors, fuse or relay somewhere between the battery and the pump.

Check your battery connections, if you hear just a click, it's usually corroded connections at the battery.

Spott said:

The click is probably the relay that's supposed to send power to the pump. I'd first measure the voltage at the pump, and see if the power is getting there. If so, then the pump has probably failed. If not, then your problem is in the wires, connectors, fuse or relay somewhere between the battery and the pump.

Click to expand...

Okay thanks.

Which wire is which? I am going to try and test the wiring without actually dropping the tank or anything (Im pretty sure I can reach the connector...) so I need to know which wires to test.

If I am right then there should be 3 wires? 1 for power, 1 ground and one that should be putting out 6v for the gas gauge?

alwaysFlOoReD said:

Check your battery connections, if you hear just a click, it's usually corroded connections at the battery.

Click to expand...

Good tip. I'll get out the wire brush and clean that all up and try it again tomorrow.

+1 on the battery connection, from your description, "moving it out of the way", I assume it doesn't get driven every day, so corroded terminals are a good bet.

There are actually 2 clicks when key is first turned on, but they happen almost at the same time.
On the passenger side engine bay there is the fuse box, under that are 3 relays, EEC relay, Fuel Pump relay and WOT(wide open throttle) relay.

EEC relay activates with the key on(click), it powers the Fuel injectors, spark, fuel pump relay(not fuel pump), and of course the EEC(computer)

When computer(EEC) gets power the first thing it does is to Ground the Fuel Pump relay for 2 seconds, the second "click", to prime the fuel system.
So second click is almost simultaneous.

In the fuse box there are a few 30amp fuses, one is for the Fuel Pump, check it first.

You can manually test fuel pump relay using the OBD1 test connector.
Look here: http://www.therangerstation.com/tech_library/OBD_I.shtml

OBD1 connector is usually on drivers side of engine bay near firewall, grey or black plastic, it is loose not attached to anything.
Second diagram in above link has labeled slots in the test connector
Fuel Pump slot is the Ground for the fuel pump relay
Turn the key on
Then use a jumper wire in that slot to a Ground, battery ground is fine or engine, or ??, as long as it is a good ground then you should hear the Relay "click" and the fuel pump should come on.
If you don't hear the "click" then you will need to remove fuse box and get to the Fuel pump relay.


Easier place to test if fuel pump is being sent power is at the inertia switch, it is in passenger side of cab in the kick panel or just above carpet under glove box.
It is a small box(2"x2") with a button on the top, 2 wire connections, inertia switch is there to cut fuel pump power in case of a roll over or accident(sudden stop), button on the top is a reset in case it is accidentally tripped.
It is a 12volt in and 12volt out pass thru
If fuel pump relay is working then either terminal on this switch should show 12volts for 2 seconds when key is first turned on.

Fuel pump power runs like this:

Battery--------30amp fuse----------fuel pump relay-------------inertia switch---------------fuel pump------Ground

Ground wire for fuel pump is usually located near inertia switch, usually.


Just for FYI, the fuel gauge sends a 5volt pulse, yellow/white strip wire, to sender in the tank, so it won't show voltage on meter, and sender usually has it's own Ground, orange wire, so there are 4 wires into fuel tank

Both wires for the inertia switch read 12v when the key is turned.

So does the red/black and black wires heading to the pump (tested above the rear axle]

When the key is turned on it (power to the pump] spikes to 12v and then drops again very very quickly (so fast the volt meter doesn't even get up to 12v half the time] Is this normal? Or should there be 12v for a few seconds?

Yes, that is not right, should stay at 12volt for 2 seconds.

Could be relay isn't able to stay closed, which can happen if voltage is low, i.e. corroded connector.

You can test Fuel Pump relay voltage at that OBD1 test port.
A relays coil is just that, a coil of wire, so when the key is on EEC relay sends 12volts to the Fuel Pump relays coil, you can read that voltage at the Fuel Pump slot on the OBD1 connector.
Red probe in slot, black probe to Ground, should read battery voltage, 12.3v-12.8v

Okay so I can't find the ODB1 test connector.

But I think I may have figured it out. The outer plastic on the negative battery cable has a big split, and the inside is all green with corrosion.

I tried swapping the relay for the power locks one to make sure that its not the relay... Upon trying to power locks I realized they are not working right. I hear the rear hatch locking/unlocking but the doors are not.

Does this seem like its likely the battery cable?

If the battery cable is not the actual cause of the problem now, it will be causing some sort of problem soon. You should replace it and see if it helps.

Surrey said:

Okay so I can't find the ODB1 test connector.

But I think I may have figured it out. The outer plastic on the negative battery cable has a big split, and the inside is all green with corrosion.

I tried swapping the relay for the power locks one to make sure that its not the relay... Upon trying to power locks I realized they are not working right. I hear the rear hatch locking/unlocking but the doors are not.

Does this seem like its likely the battery cable?

Click to expand...

My bad, looks like the self test connector(OBD1) is on the passenger side on an '89 Ranger.
Below the fuse box is the relay box, which you have found since you swapped out the relay, test connector is in the rear of the relay box, end closest to the firewall.

Diagram here: http://www.2carpros.com/questions/1989-ford-ranger-obd1-location


Yes, for 12volts to be 12volts there needs to be 0volts(ground) otherwise there is no flow of voltage so no "power".

Vehicle grounds can be tricky as anyone who has tried to wire/hook up trailers lights can attest to, lol.

Engine/trans is isolated from body and frame by rubber mounts, body is isolated from frame by rubber mounts, body parts are isolated from other body parts because they are painted before assembly.

Starter motor and alternator need and provide the most voltage(amps) so larger Ground cable from battery goes to engine, then there is often a small wire on negative battery terminal to the Rad support, for head lights, and a jumper from there to the inner fender for starter relay and other devices grounded to that fender.
There will be a ground strap from engine to firewall, for cab electrics
Ground from engine to frame for tail lights and often fuel pump

Over the years any of these can rust and corrode.
And if you can't find a ground strap between parts of a vehicle then add one, you can have one too few ground straps, but never one too many


If you swapped relays and the problem followed the relay, i.e. door unlock quit working then it would seem to me the relay is the problem.

Yeah I would start with a new relay. Then I would make sure the engine would turn over with the existing battery. If it does not then next would be new battery and cables.
PERSONALY I replace my vehicles batteries every 3 years! I NEVER want to be left out there with a bad battery again! Another PLUS is corrosion, By renewing batteries frequently my under hood parts don't corrode! My cables stay new looking and never need to be replaced. Old batteries cause lots of problems while going away.
Big Jim

RonD said:

If you swapped relays and the problem followed the relay, i.e. door unlock quit working then it would seem to me the relay is the problem.

Click to expand...

The problem didn't follow the relay. Both relays didn't work for either the power locks or fuel pump (and they both worked a few days ago so I can't imagine BOTH relays are blown]\

And its not the battery. Just got it and its turning over the engine perfectly fine.

I have a length of 4-gauge wire to make a new battery cable with so hopefully that'll fix things...

Negative battery cable was bolted to the frame and to the engine.

I made a new cable, but it's only bolted to the block (couldn't find the sort of bracket used to bolt it to the frame and now i can't find the bolt that held it in place...)

Still nothing works right. Power locks are weird and fuel pump is only getting a spike of power. There is a little wire coming from the relay box to the negative cable. I connected it to my negative cable but still nothing.

Im starting to think that connection to the frame is vital??

The grounds to the frame and to the cab firewall are vital. Engine, etc. is isolated from frame by rubber motor mounts and rubber bushing in the spring hangers. Cab is isolated from frame by rubber mounts. Computers run on something less than 9 volts. With such low voltages you need really good grounds!!!