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Discussion Starter #1
First things first, I'm going to swap them out when the rain stops. :goodfinge

The truck ran fine last Sunday when I moved her to work on the car. Was going to take the truck out for a drive on Thursday night, and she wouldn't start; no fuel. Yesterday, I diagnosed that both pumps work, and I can jump the F/Pump relay to turn them on. Found some exposed wiring between the main harness and the EEC Power relay, so fixed that. I ran out of time to go any further.

Questions:
Does the EEC relay trigger the F/Pump relay?

If I jump the F/Pump relay (Y to P/BK), the pumps work, but the truck won't start. I suspect that there is an "ignition" signal missing when I do this, which is why I think that the EEC Relay signals the EEC, which in turn signals the F/Pump relay. Am I on the right track?
 

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yo Chris!
Yes...
"...When the ignition switch is ON, it turns the EEC power relay ON. The EEC power relay provides power to the powertrain control module (PCM) and the control side of the fuel pump relay. Power for the fuel pump(s) is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flows through the fuel pump relay and inertia switch to the fuel pump(s). The fuel pump relay is controlled by the PCM. When the ignition switch is turned ON, the fuel pump(s) will operate. If the ignition switch is not turned to the START position the PCM will shut the fuel pump(s) OFF after 1 second. The PCM will operate the fuel pump(s) operate the fuel pump(s) when the ignition switch is turn to START position to provide fuel while cranking. After the engine starts, the PCM will continue to operate the fuel pump(s) unless the engine stops, drops below 120 rpm or the inertia switch is tripped..."
Source: by Chilton via AutoZone

Your analysis is same as mine; ck EEC relay/"socket"/wiring first
 
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:banghead I just found that I have the same problem.. recently we had a rash of people stealing gas... we are already at $4.00 a gallon... so I put a few gallons in mine to see if that worked... but no such luck.... waiting on AAA to take it to the shop now... I'll check back later and let y'all know what happens...
 

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Discussion Starter #4
yo Chris!
Yes...Your analysis is same as mine; ck EEC relay/"socket"/wiring first
Thanks Mike.

Yesterday was brutal. I was supposed to be wheeling (until this happened), then while diagnosing, I had no internet when I needed it, my PC changed the drive letter on my external drive so I couldn't figure out why my AllData wasn't working, then it started to rain for a bit. Almost like somebody was trying to tell me something. :banghead

Tomorrow is supposed to be sunny, so I'll get the new relays installed and check for a "12v ignition" to the EEC Power relay.

Maybe I can hit the trails this weekend. :popc1:
 

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If your relay doesn't fix the power, check the fuse links by the solenoid too. I went through this a while ago and actually found it cut not burnt on the truck I was fixing.
 

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OMG....

:beerOk.... this is different... try checking to see if you have fuel pressure... Mine was fine... turns out my distrubuter is what whent bad... it's barely turns.... so thats being replaced as we speak... $130.00 for the part... and 1 hour labor... YAY!! Soon to be on the old mud trail again!! :thumbup
 

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Discussion Starter #7
If your relay doesn't fix the power, check the fuse links by the solenoid too. I went through this a while ago and actually found it cut not burnt on the truck I was fixing.
Thanks. That was the first thing I checked, as that link went on me a few years back. Didn't realize it was their until after the new F/Pump relay and frame pump were installed. :banghead



... try checking to see if you have fuel pressure...
I did. No running pumps = no fuel pressure. :toothless
 

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:banghead I just found that I have the same problem.. recently we had a rash of people stealing gas... we are already at $4.00 a gallon... so I put a few gallons in mine to see if that worked... but no such luck.... waiting on AAA to take it to the shop now... I'll check back later and let y'all know what happens...
$4.00 a gallon ??????:shocked

That's more than Canadians pay :shocked Does Arnold know what's going on;)

I feel your pain Kritter. Next time I'm at the parts store I'm "investing" in a locking gas cap.

Seems a lot of locals have been hit and I think I have too. These idiots are ripping people off and pumping water in so they won't notice the level is down.

Twice lately I've stalled out due to water in the gas, and I run ethanol which should pass condensation no trouble at all.

What [email protected]&#ing @r$eholes !

Sixlitre
 
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Discussion Starter #9
Ok, the EEC Power relay has no constant 12v and no ignition power. This is gonna be fun. :cry

Edit:

I am such a retard. I've been working with the Fuel Pump cut-off relay, not the EEC Power relay! :banghead:banghead
 

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Oddly enough I had the same, or at least a similar, problem a couple years ago. Against all odds it seems that both the Fuel Pump relay and the EC power relay died at the same time. At the time I refused to believe it, but replacing both relays fixed the problem. Freaky.
 

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Discussion Starter #11
Oddly enough I had the same, or at least a similar, problem a couple years ago. Against all odds it seems that both the Fuel Pump relay and the EC power relay died at the same time. At the time I refused to believe it, but replacing both relays fixed the problem. Freaky.
Really. That is good to know Dave. When I get home tonight I'll go after the EEC relay and see what it is or isn't doing.
 

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It happens Chris...I have my wife checking everythAng I do on the Bronco or around the shop now.

Those relays last only so long as Dave mentioned; also corrosion sets in in the connectors and also the wire strands as our pal Sixlitre has pointed out in the past. Steve83 has a write-up on swapping to the Bosch relays;

and a Chilton wiring diagram for the relays fig 18
for eec relay
 
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you can get used relays from the j/y for a five finger discount (free), instead of having to buy all the parts like I did :duh
 
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Discussion Starter #15
Why does every wiring diagram show different colour wires? :banghead

So, I found the EEC relay for sure this time. It is getting ignition via the Tan/LB wire (could be dirty white/LB), but no constant 12v via the yellow wire.

The other wierd thing is that there is no red wire. Instead, there is a brown fusible link right off the relay.

Me thinks that my constant 12 v source has a break, which means that this job is going to get ugly, as the harness goes through the firewall right above the transmission. Oh yay! :banghead

I think I will leave this until the weekend when it is warmer and lighter.
 

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Discussion Starter #17
use the EVTM's they are the bible for wiring projects
For sure. Funny thing is that the ignition wire for my EEC relay looks to tan/blue, but the EVTM's say it should be white/light blue. That's what you get when the relay is right next to the floor vent. :histerica

For future reference, by EEC is right behind the little storage pocket in the dash, to the right of the steering column.

When I get home tonight, I am going to jump 12v to the yellow wire, and see if she fires up. If she does, then I will continue looking for the break in the wire.
 

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Discussion Starter #20
I actually believed AllData and Mitchell's and went hunting in the kick panels. :doh0715:
 
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