86 Ranger fuel pump problems

[nova801428]

My 86 Ford Rangers fuel pumps don't come on, I bought a relay switch and they still don't work. I took out the enertia switch and I put it back in, but how do you reset it. Please help any suggestions please?

 

[Brian_B]

Push the button on the inertia switch to reset it. I think its red on most models (was on my 89 anyway).

Do you have a multitester or a 12V test light? If so, start at the pump and work your way up and see where you have electricity. Pump---->inertia switch----->relay. Check all the connections for corrosion as well as being loose. If they are corroded, clean and use dialetic grease on them. Hook them back up and start over.

If you have electricity at the pump and all the connections are good (including ground), you probably have a bad pump.

 

[nova801428]

Where can you find dialect grease at?
Thanks I will try that

 

[Brian_B]

Any parts store...probably wal-mart. It a grease that conducts electrical current. Most factory connections have it in there. I see people remove it thinking its not supposed to be and then the rust/problems start.

 

[nova801428]

could I have bought the wrong relay switch, what does it look like, because on Napa it shows a different picture than the one I have. I can send power through the relay switch and then they both come on, could it be a sensor that I don't know about. Have you ever solved a problem using dialect grease, and should I use a peice of wire where the enertia switch is and try to bypass it? thanks for your suggestions.

 

[Brian_B]

I do not know what your relay looks like for sure. On my 89 ranger it was on the bottom side of the power distribution box. I think mine was green. I do not know if yours even has the same set up.

I am not sure I understand this part. When you put current to through the relay they come on? If thats true, there is the problem. As far as the intertia switch being bad, you can test it by jumping a wire across it and see if it runs. Do not drive it like that though! Its totally unsafe!

 

[nova801428]

What do you mean there is a problem? Electrical problem? Was your fuel pump relay rectangular? Where would the problem be. Have you had fuel pump problems before?

Here is what happens: I bought a 1986 Ford Ranger with a 2.9L V6 for $300 with fuel pump problems, the guy said that when he was going down the road the truck died. He get the truck home and lets it sit, then later tries to start it then it starts and then dies. I got the truck home and took off the fuel line and saw that no fuel was coming out. So I got help to test the wires coming from the enertia switch and no power was coming from it. I thought that it was the fuel pump relay, so I went to Shucks Auto parts store and the gave me the fuel pump relay for $28 (which I don't know if that is the right one, I think they gave me the eec relay). and I replaced the part and I tried it but no fuel was coming out, so I used power to jump the fuel pumps again and they came on. so here I am asking you what the problem is and after 2 weeks or so I will have to take it some where, where they can diagnos it for me, then I can fix the problem myself. Thanks for helping me, and have a great and happy new year!!!

 

[Brian_B]

I cannot tell you exactly what the problem is. I am not there to test the current. Until you know where the power stops, you cannot fix it. If its getting power to the relay and not out of it, thats where the problem is. If its getting power to the inertia switch and not out of it, thats where the problem is. All it takes is a $1-2 12V test light to find out what has power and what does not.

As far as mine, It was a square and plugged unside down into the bottom of the power distribution box. Mine was a totally different year though. I have no clue where yours might be.

You used power to just the pumps...from the battery directly I assume. If the pumps are working with them jumped, its an electrical problem. You have to test to find it. If you or a friend cannot do that, then I suggest a shop.

BTW: The last fuel pump relay I bought was around $13. The inertia switch was about the same. Mine only had one pump (in tank) and was around $70 when it went out. Just so you know, I drove it 16 years and my brotehr has it now. I replaced a lot of things over that many years.

 

[nova801428]

I have a test light to test for electical current, today I am going to test everything from the battery to the fuel pump. Thanks for your help

 

[DeRocha]

A meter would be far better than a test light.. If you test the wires (both will be the same) @ the inertia switch they will read 12v for a few secs after you turn the key to run or if the engine is cranking (the circuit samples the tach wire and shuts down the pump if RPMs =0) otherwise the wires will read approx 6v...

Search on fuel pump for other threads such as fuel pump electrical problem

 

[nova801428]

Does it matter if the wires are not the same voltage? So, should I test the wires that are coming into the relay switch. I am getting power to it, and I can send power from it?

 

[DeRocha]

Does it matter if the wires are not the same voltage? So, should I test the wires that are coming into the relay switch. I am getting power to it, and I can send power from it?

Yes...the inertia switch is sort of like a light switch in your house... In the Normal position it is always on so whatever voltage is sent to it will pass through it (therefore both wires will be the same voltage)... Now if the switch is triggered it will be in the off position and the voltage on the output wire will be zero regarless of what voltage is on the input side..

 

[nova801428]

So, the way to reset the switch is by pushing the button on the top. I have already tried that and the fuel pumps don't come on, I am going to test the wires from the battery to the fuel pump. Could it be the eec-IV?

 

[410Fortune]

Jumper the intertia switch and see if the pumps come on.

Here is how it works:

The PCM (EEC) sends a signal to the fuel pump relay when the key is turned to on
So testing for 12V+ at the relay will tell you if this signal is being sent.
The relay then sends 12V+ to the inertia switch through the fuel pump fuse
It then leaves the inertia switch and goes to the fuel pump via a black/pink wire
The black/pink wire on a 86 should have a single wire connector just below your brake booster. Check this connection.

So basically:
Check for 12V+ at the relay and fuse, jumper the inertia switch, check for 12V+ at the pump when the key is on

this will tell you if the pump(s) are getting power.

Also check the - side of the fuel pump wiring (obviously)

 

[nova801428]

but, what if none of this works? I have a three day weekend to fool around with it. I will certantly take your post to consideration.
Thanks, Nova

 

[nova801428]

How many wires go to the fuel pumps?

 

[nova801428]

does anybody know a basic price of a diagnos? will it work,or just screw me over?

 

[BrooklynBay]

The computer also controls the power going to the fuel pump. If you have no check engine light, you won't have a working fuel pump either. Check the small ground wire near the battery, and any fusible links that you might have (if your year model has them).

 

[nova801428]

will the motor still turn over if the light is not on?

 

[BrooklynBay]

Yes, the motor will still turn over. The starter is a separate circuit, which is basically the starter solenoid, ignition switch, starter, and battery. Starter kill in an alarm only disrupts the power coming off of the ignition switch's crank position when you turn the key. This basically kills power going to the starter solenoid. The starter kill relay cuts power going to the starter solenoid's coil. In the 93 Aerostar with a 4.0 engine, the starter has a built in solenoid, besides the one on the inner fender well. This has 2 solenoids, which isn't too common.