Hi all,

I have a new to me 94 F150 4x4 with the 300 6 cyl and a 5 speed about 170k miles. Single rear gas tank.

I picked this up recently from Virginia. Engine sounds good and ran nice around the shop all winter.
I just put it on the road, drove a few miles and it died and won't restart. Cranks fine, has spark but no fuel.

History. The guy I got it from just put in a new fuel pump to fix a no running issue, right before I got it.

I need a wiring diagram so I can check for power from front to back. A good component location pic would help also.

Would appreciate any tips and advise on what usually happens with these trucks.

Thanks,

Joe W.

94 f150 300 6 5 speed

97 f250 7.3 powerstroke

 

Here is diagram of the electrical:


Fuel system diagram:

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Thanks!

I know I should have a manual. But this is new to my always growing fleet of old iron. I will be looking for one to buy.

Appreciate any and all help.

Happy Mothers Day to all the moms out there.

Joe W .

 

When the fuel pump does not run you need to ground pin #6 of the self-test plug or short pin #2 to pin #6 and turn on the key. Then test the fuel wiring with a test light.

Note if the fuel pump will run with pin #6 grounded and with the key on but will not run for one second each time the key is turned on then you may have a bad PCM Computer.



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Bill,

That's exactly what I needed.

Thanks again!

I let you know what I find.

Joe W

 

Update,

Took a quick look/listen earlier. Grounded #6 koeo, relay clicks and I have power at both sides of inertia switch, checked with a test light.
Did not check specific voltages.

I will go out later and check for power at the tank connector.

Joe W.

 

Just checked a little further.

First thing I found is a round connector spliced into the end of the harness at the fuel pump connector. It is a marked ford part. Isn't a 94 a straight plug?
But I do have power and ground through that plug.
Also, the fuel gauge reads way past full. I grounded both sending unit wires, no change.

I then ran 12 v and a ground wire to the fuel pump side of the connector and don't hear anything.

Unless you guys tell me I am missing something. I will be pulling the tank and replacing a pump.

This is the 2nd pump they put in it. I am sure they are cheap part store pumps. But I question if they could have gotten 2 bad pumps in a row.

Any thoughts? I know there are a lot of junk parts being sold today.

Is there anything that makes these trucks eat pumps?
They cleaned the tank completely last time also.

Thanks,

Joe W.

 

If you grounded the yellow wire with a blue stripe with the key on and the gauge read passed full there is a problem between where you grounded it and the gauge cluster.

Have you had the cluster cover off and back on?
If so you may have not plugged the jumper on the cover back in.

It should have a round plug:


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Hi Bill,

Good, I'm glad it has a round plug. Weird thing is, is that's it's spliced on. It's a nice clean job with shrink wrap and ford tags. Does that sound factory?
I can get a pic.

I will check that wiring to the gauge cluster.
No, I have never had that apart. But prior to me, who knows.

I am draining the tank right now.

Not sure if I will drop it tonight or tomorrow.

Thanks again for your help!

Joe W.

 

Hi all,

I spent some time on the truck. Pulled the tank, found yellow wire from sending unit broken.
Big news though is the fuel pump tests good on the bench.

So, I went back to the truck and I confirmed power to the pump.

I checked the ground side by running a test light from the battery positive, to the fuel pump connector negative. The test light lit up? (This part confuses me)

So I plugged the fuel pump back in and hit the key, nothing.

I grounded #6 under the hood and ran a hot wire from the battery positive to the pump.
Touched the hot lead from the battery to the positive side of the fuel pump, nothing.

I then ran a neg wire from the battery and touched the negative side of the pump and it fired up.

Then I disconnected the #6 ground and repeated the tests. This time the pump wouldn't run
Unless I touched both hot and positive side of the fuel pump.

Looks to me like I am not getting a ground signal from the computer.

I could definitely use some help on this one.

I am going to go out and pull the computer and give it a smell test.


Thanks,

Joe W

 

You did not say if you had the key on or off in any of the tests.
When you say pin #6 I take it you are talking of the self-test connector.
When you say "Looks to me like I am not getting a ground signal from the computer." are you talking about to the coil of the fuel pump relay?
The computer does not supply a ground to the pump itself.

 

Oops, I had the key on during those tests.

Yes, pin 6 of the self test connector.

Yes, I went back and looked at the diagram after I wrote and saw the computer doesn't ground the pump.

But what exactly does?


I just opened the EEC. Do not smell anything.

See light brown coloring under blue capacitor. But I can't tell if it means it's burnt.

Took some pics. I will try to load them.

Thanks,

Joe W.

I added some pics of the EEC to a album under my user name.
I did not see how to link them here.

 

The fuel pump grounds to the radiator support on the drivers side, G100.



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Wow, way up there.

I will go out and check those.

Thanks again sir,

Joe W

 

Ok, went out and cleaned the grounds and the negative battery side.
Everything nice and tight and clean. Same thing.

But I can get the pump to turn on and run for a couple seconds when the key is turned on, if I run a separate rate ground wire to the fuel pump negative.

So it looks like the ground wire to the pump is open some ware between the radiator support and the pump itself.

I will check it tomorrow.

Would I be bypassing anything if I just run a new ground wire?

Thanks,

Joe W