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?

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.

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

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.

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.

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!

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!!!

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. :p

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

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 (http://www.explorerforum.com/forums/showthread.php?t=149271)

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?

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..

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?

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)

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

How many wires go to the fuel pumps?

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

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).

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

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.

could the eec (electronic engine control or computer) not work? and that could be the problem? How much do they cost? I have two of them; one installed and the other sitting. Is it bad to change them?

How much does a eec cost?

should I take it to get it diagnosed?

does anybody know a basic price of a diagnos? will it work,or just screw me over?Depending on the shop your looking at $65/hour for them to trouble shoot. A descent shop should be able to find the problem in an hour :thumbsup: , a not so descent shop may never find the problem (but will offer to replace components until the problem is fixed :thumbdwn: )

yes it is possible the PCM is bad itself. They are $350+ new, $35-65 at a junk yard.

You NEED TO TEST the wiring at the fuel pump relay and fuse for power before you start throwing $$$ at it.
Being a 86 model it is VERY likely that your wiring is old and brittle and has issues, trust me.

Just keep in mind as mentioned before, the fuel pump will only have electrical power to it for just a few seconds when the ignition is turned on without starting the engine. I don't know where electrical power to the pump is shut off but I would guess that happens at the relay.

i think I figured it out. O.K., I replaced both of my relays and the pumps don't work, so I messed around with the relays and noticed only one clicks. So, I figured out that one of the relay plugs is bad and then I bypassed it and they came on. I tried to start my truck and it won't start. So I took off my cap and rotor and were both corroded! Awsome! Thanks for the help that this forum has gave me.

I'm having the same problem. I'm getting power to the relay, but no power to the inertia switch or the pump. I have a 2000 ford ranger. help if at all possible

So, nothing has worked yet. I can dump some gas in the intake and it will fire, but nothing yet. Please help

Instead of bypassing the wiring, try to put in new relay sockets. After you do this, listen for the sound of the pump turning on for a few seconds, then turning off. Try to start it after this.

Are you talking about relay connectors? I already replaced the fuel pump relay connector and it made no difference. I took off the fuel hose and turned the key on and no gas came out. I also took off the fuel filter between the pumps. I also have no engine light on and I no longer has spark. I replaced the coil today , thinking it was the problem, and I still have no spark. Why won't this ranger work? Can the pumps be so weak that they don't provide enough power for the gas to be pressurized for the engine, or are the pumps messed up and they don't want to operate but only when I jump them?

right next to the fuel pump relay is another realy (looks just like it ) change that one to ,,,,i had the same problem with my 91 i changed the pump relay nothing,then i took the old pump relay and change the next relay with it ,,and it runs great now.could be something diff on your ,but i,d try it........you can use a jumper wire on your pump relay to ....too make your pumps run too just to check pressure though not for driving

I replaced both the relays (fuel pump and eec) and did not work. There seems like there is not enough pressure to run even if I jumped them. but, now I have no spark!
Just keep getting bigger problems by the minute. Thanks for the suggestions

I replaced both the relays (fuel pump and eec) and did not work. There seems like there is not enough pressure to run even if I jumped them. but, now I have no spark!
Just keep getting bigger problems by the minute. Thanks for the suggestions
if you jumped your relay and it didnt run your pumps constently ,then ether your fuel pumps are shot or there a short in your harness to them??far as spark,i didnt have any ether with mine,if there a problem with the fuel delivery system ,or the ingnition module the computor dosent let it spark......sorry i cant be more help

Please help.......I have no power to pumps when key is on, I can jump the pumps and they turn on, relays have been replaced, enertia switch is fine, I get power from the igntion to the relay, I get power from the battery all the time, and when I ground all of that including the fuel pumps on the relay, they jump on but they do not shut off and they stay on for ever unless I unground it. The eec should ground the pumps for three seconds, I replaced the eec too, when I turned the key, the pumps came on and it has not since came on. I have ran and drove my truck before, it just died.....please help

Check the fusible links.

already did, forgot to mention that. I checked them by pulling on each wire coming from the fusible link and if wire doesn't come out of it, then it is fine, is that how I am supposed to check to see if they are good?

You need to use a continuity tester.

can't I just test how much power I am recieving from the fusible link and how much power I get off of the battery then minus the difference?

You could test for power coming off of a fusible link. You shouldn't see a noticeable voltage drop right after the link.

All the fusible links are fine, whats next?

Did you check for broken ground wires near the battery area?

Yep, they are all fine

okay so your fuel pumps both come on when you jump the relay, correct?

you have 12V + constant (from the battery) to the relay hot all times, correct?

But when you turn the key the fuel pumps do not prime like they should. even with all new relays, correct?

You still have no spark?

Where in OR are you? You have no city in your profile.

okay so your fuel pumps both come on when you jump the relay, correct?

you have 12V + constant (from the battery) to the relay hot all times, correct?

But when you turn the key the fuel pumps do not prime like they should. even with all new relays, correct?

You still have no spark?


Yes or ground the relay, Yes and from the ignition, Yes thats correct

I have spark, I have left the key on a couple of times and screwed up the coil. Replaced it and I now have spark

I took my truck to a local shop, and a mechanic told me it was the computer that was screwed up. I bought a new computer and will be here tomorrow, he is going to install it, the correct way not like I did. Hope it works out fine though


Where in OR are you? You have no city in your profile


Sorry, I am not on this site a lot, I am also a member of a few other sites. I live in a small town called Jefferson, its between Salem and Albany along I5. I was in Sisters at a High School Basketball tournament a last week when it snowed heavily along the pass, and when I went home their was two accidents (one, a honda civic/accord was totalled, the driver and passengers were both killed, I guess truckers said that it blew the aluminum heads off of the engine (BTW they hit a truck head on) Then the second was a roll over at the 20/22 split. I stayed at the Super 8 motel by Wal-mart. I don't know bend that much but I do occasionally go dirt biking at East Fort Rock. Where in bend do you live?

The computer may/ may not be faulty
it appears as if the computer is not telling the fuel pumps to prime and then to run when the engine is cranking or running.

The means 1 of these things:
computer is bad (usually other circuits fail, you get a mess of codes, etc)
computer is not getting signal from key switch
computer is not sending signal to fuel pump relay

The EEC relay is what controls power to the computer.

it is quite possible that this is a broken wire somewhere, a bad terminal/clip/pin in the relay box itself. You are getting battery power to your power distribution box, but not the EEC power feed when the key is ON



I hope you dont pay $300+ for a computer, and if you did I hope it fixes the issue.

I'm in Bend and figured if you were in the area maybe we could get together and figure this thing out. Weird, I was in Corvallis last weekend playing music in a band and drove over the pass going your way. I also stayed next door at the Holiday inn on new years night.......... :) OMG, we've found the reverse of each other! How weird.........Ha!

Cool, you found the ignition problem, that makes things easier.

410fortune has the right question - you DO have 12 volts to the relay, right? As I remember this the ECU grounds the relay to opperate it so you need the 12 volt on 2 terminals at the relay, the main power feed that gets switched in when the relay operates, and the feed for the relay coil (which the ECU grounds the other side to opperate it).

If the pump runs when you ground the ECU wire at the relay then the problem is upstream from the relay, either the wiring, the impact switch, the ECU (not likely actually in my experience), or the signal telling the ECU to ground the relay. I don't have a wiring diagram in front of me to trace this down but that is the jist of it. Maybe somebody here has a wiring diagram handy? The next place I'd go would be identify the FP relay wire at the ECU, disconnect it and ground it. If the pump runs then go upstream again.

Eeek whisperer the relays get a power feed from the computer when the key is switched to on.

true the fuel pump signal may be a - but the red acc + wire powers many relays and sensors in the engine bay. the power for this red wire comes from the PCM and the PCM draws this power from the + feed att eh EEC fuse.

confusing I know, the red wire is + and goes to each injector, the coils, the MAS, the TPS, etc etc
it powers the fuel pump and AC WOT relay as well.......
if you dont have 12V+ at any of the red wires, the first thing to check is the EEC fuse and relay.

Eeek whisperer the relays get a power feed from the computer when the key is switched to on.

true the fuel pump signal may be a - but the red acc + wire powers many relays and sensors in the engine bay.

OK, confued as to the Eeek. He says the pump runs when the relay is jumped out so the actual pump 12V feed (goes through the relay when opperated and to the pump) is live. What did I miss. The other 12V feeds one side of the relay coil and the ECU grounds that to pull in the contacts. At least on all other Fords of this vintage that's how these work. What are you seeing in the diagrams that are different about this?

The question is what did he jump? - or +
are both + feeds to the relay showing 12V+ when the key is on

one is constant 12V+ at all times
the other is switched 12V+ when key on

As I understood what he wrote he has the 12V+ from the battery but never gets the 12V+ with the key on.

Of this is the case I would check for 12V+ at one fuel injector when the key is on (red wire 12V+ Acc feed from PCM)

The question is what did he jump? - or +
are both + feeds to the relay showing 12V+ when the key is on.

Gotcha, I just think in the terms of jumping the relay by using a jumper wire on the relay. Just where my mind goes.....

Ok then, I'd pull the (supposed to be) switched wire from the relay connecter insert a wire into the relay connector and wire that to a 12V source. Then turn the key and see if the pump runs. That would test the entire circuit to the relay from the ignition switch. (ASSUMING that the ECU is grounding the relay coil like all the others). If that's is the case it get's down to a fairly simple curcuit supplying 12 volts switched to the relay.

I jumped hot +12 volts form the battery at the fpr to the fuel pumps, and they both jump on. This thread is really old and not really up to date. So, the pumps don't come on when the key is on, also when cranking they don't come on. When I jump the pumps and try to start their is not start but i have spark, meaning that the injectors are supposed to be pulsed from the eec, and I think the eec is shot, I bought an eec before and I neglected it (put it into my truck without disconnecting my battery) probably causing to to fail. My mechanic could not pull codes from either computer in my truck (one from a junkyard and the other was original). I bought a new computer from NAPA, because my mechanic told me both Shucks and Knects sell junk, most of their stuff might work but they slap a label on it and sell it...so I bought from NAPA for $100. I got my computer in today and I am going to give it to my mechanic tomorrow and well see what he figures out with it.
Thanks

it is quite possible that this is a broken wire somewhere, a bad terminal/clip/pin in the relay box itself. You are getting battery power to your power distribution box, but not the EEC power feed when the key is ON


Nope, I checked it out thoroughly and my mechanic also told me all the wires were fine, he just couldn't get a signal out of the computer to pull codes.


you DO have 12 volts to the relay, right? As I remember this the ECU grounds the relay to opperate it so you need the 12 volt on 2 terminals at the relay, the main power feed that gets switched in when the relay operates, and the feed for the relay coil (which the ECU grounds the other side to opperate it).



Yep, I get 12 volts from the ignition when the key is turned on and I get 12 volts from the battery constant. But, when I ground the relay, my pumps jump on and do not shut off...meaning that the eec controlling/grounding the pumps for 3 or so seconds does not work.



if you dont have 12V+ at any of the red wires, the first thing to check is the EEC fuse and relay.


I have 12V everywhere I need it, just not the pumps. Checked the fuses at least 20 times



Ok then, I'd pull the (supposed to be) switched wire from the relay connecter insert a wire into the relay connector and wire that to a 12V source. Then turn the key and see if the pump runs. That would test the entire circuit to the relay from the ignition switch. (ASSUMING that the ECU is grounding the relay coil like all the others). If that's is the case it get's down to a fairly simple curcuit supplying 12 volts switched to the relay



That would work if I wasn't getting any power from the eec at all, but I am, its just not grounded and I checked all grounds. I even replaced the battery cable clamp post things and ran a wire from one ground to another several of times in hope of getting my pumps to run.




As I understood what he wrote he has the 12V+ from the battery but never gets the 12V+ with the key on.



I am getting 12V+ from the ignitions when the key is turned on, thats what is making this so confusing.

I have seen 4 EEC-IV computers fail in my time, it is very likely the power supply circuits in your PCM are shot. My fingers are crossed your new PCM fixes the issue.
Before I bought a computer I would have also checked for the ACC 12V+, with key on, at an injector and other engine sensors.
This would tell you if the problem is the entire computer power feed or just the relays.


Let us know how it goes!

On my BII I have had it all happen.
I have had broken coil wires, bad - wire to the fuel pump, bad battery cables, bad alternator cables, a bad/old PCM, a PCM got fried by the exhaust shop (left key on when welding, genious) bad relays, bad relay wires, shorted power wires, bad fuel pump connection, bad ground strap, etc
Shes 19 years old has 290K miles on her now and no issues, every wire I installed.

Nope, my mechanic told me my peice fo shit didn't work. I bought a new computer from NAPA. Except the part number is different than what I am supposed to really have in my truck. But, I looked up eec numbers and it simply does not exsist??? This really pisses me off, also their is a rattle in the computer when I bought it, and the ####ers at NAPA said if I even take off the plastic wrap around the eec, I could not take it back, but the eec was never wrapped in anything. So, I am either going to start throwing fist or throw my truck off a damn cliff. Any ideas?

check for power at the injectors when the key is on

How is that going to help me? Is a rattle in the computer a problems, my other computers did not rattle

if the new Napa computer is defective return it
when you have a PCM plugged in, turn the key on and check the red wire at an ijector for 12V+, this will tell you if the PCM is powering up all the engine sensors, relays, etc. If not then the power feed from the PCM is bad, or the EEC relay/fuse and power feed to the PCM is not working

If their is no power to the injectors will the fuel pumps still come on? I remember testing the red wires and they were hot, what does that tell me?

that tells you, again, that when you turn the key to on the computer is switching power to all the sensors and relays, etc, if you are not getting this power at your relay then the problem is in the wiring

Which relays? I am getting power to the fp relay and the eec relay, I haven't checked the others yet

there should only be one more under the hood right? Its the AC WOT relay

when you say you are getting power do you mean with the key on or the key off?

key on. Actually, I think the WOT relay is inside the eec, because my diagram shows red wires going to the WOT, but their is not one, just goes straight to the eec....TPS maybe

Problem fixed....nothing to do with the fuel pumps at all

So it was the relay(s)?

well?????
hahaha

Nope not the relays, it was an egr sensor or relay that caused a dead short (something like that, my mechanic told me so) and in turn it caused the computer not to work at all. Now everything works, except my fuel gauge

nice!
Mechanic likely hooked it up to a pinout box and found the issue quickly

Your fuel gage is most likely the sender in the tank or wires to it at the tank

Do you think that could be the problem that was with my truck....others think it intermittently went on and off when a wire was wiggled? Doesn't make sense at all.

If you know the color code of the wire from the fuel sending unit, then you could test its output to see if you are getting a reading. The sending unit is a variable resistor.