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Discussion Starter #1
My 1990 bronco with a 302 EFI isn't running correctly.



Today I drove it just 1/2 mile, and she started bogging, so I brought it back home. The CEL was flashing... staying on solidly, went off, and the truck ran fine, then it started flashing again, and then stayed on.



I pulled codes and got a 56 and 69 they are transmission codes.



I figured I would start her up and let her warm up so that I can properly pull codes, and noticed that the fuel pump did not shut off after a couple of seconds.



I checked the data link self test connector and the Tan/Green wire that when grounded triggers the fuel pump relay. That wire was shorted to ground. I pulled the relay, and still shorted to ground. I pulled the connector to the PCM, and the short cleared.



I'm thinking bad PCM. Could it be anything else?
 

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yo Joe,
Also check that EEC relay for ground
I guess that diagram above is by Seattle Bronco?
So see his other ones showing relation between EEC & FP Relay think it's Red wire thru Splice, etc.

 

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Joe, Check EEC Power Relay (BROWN Connector)
Pull it to see what happens
 

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Discussion Starter #5
Hi miesk5,
Yes that is seattle's diagram,
I'll run outside and pull the EEC relay, and then check to see if the Fuel pump relay trigger side is still grounded.
Be back in a few.
 

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Discussion Starter #6
Wow! trying to pull that eec relay was a bitc#$!
That didn't make any difference, the trigger side of the fuel pump relay is still grounded.
 

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Wrenching for a Livin'
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i dont say this often, but that does sound like a bad eec. Good thing is, it should be easy to find one in a junkyard
 

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Discussion Starter #8
This is probably unrelated and just coincidental.
Essentially, I never use the alarm, and I almost never use the truck.
Saturday night I was trying to help someone with a possible alarm problem and went out to see if mine would crank with the alarm set. I couldn't set the alarm to test it... I figured that the battery to the remote was dead. I moved the switch and pushed the button on the driver's side kick panel, and no change. This morning I put a new battery in the remote, and still, the remote start, and the remote door locks do not work, nor does it set the alarm.

I have no idea how long the remote has not been working.
 

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yo Joe, Check the EEC's Ground
 

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Is the EEC inside the driver's side kick panel?
Does it come out from the inside of the cab?
yo Joe,
It is in driver side kick panel; but in your yr I THINK it needs to come out thru engine bay; later years have a 10mm bolt @ center of connector, pull connector, remove nuts & pull EEC & seal into bay.
 

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Yeah, i should have added that, check all fuses, check grounds and powers at the eec connector first.

If you have some alarm that enables the car from starting, you might want to remove that to eliminate it from the equation.

Normally when the fuel pump runs continuously, because the eec is commanding it on, there is something screwed up in the eec. It can sometimes be a bad ground, or low power.
 

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Discussion Starter #13
Thanks guys,
Mine does have the 10 mm bolt holding the connector in place. A little bit of a PIA to get to. IIRC the EEC ground is near the driver's side hood hinge. I'll look for it later tonight. It'll be dark by time I get home.
Al are you thinking that if the EEC ground is bad, it may try pulling a ground elsewhere?

I'm thinking/hoping that I can pull the EEC, take it apart and find moisture in there that once cleaned up, everything will be dandy. LOL... what are my chances?
 

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yo Joe;
if the EEC ground is bad, it may try pulling a ground elsewhere?
Could be Joe; check that Grnd wire in ckt 57 to the splice S102; or if that wire is shorted to ground; in case ckt 57 wire is not shorted to ground & the ground is there with the key on, engine off , then have to suspect da EEC
in 96 S102 Engine control sensor harness, near T/O to brake warning resistor/diode assembly; IIRC, brake warning resistor/diode assembly is in brake fluid level switch harness

in FP Relay ckt 97m T/LG if that wire is shorted to ground
What Brand alarm Joe? The starter disable allows engine to continue running after it's switched OFF, but won't allow it to be started. This will preserve the clock & radio memories, and confuse most thieves since every other electrical device will work normally. It will appear that the starter is defective.
 

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yo Joe,
With pump is running, unplug the EEC, if the pump turns off, the EEC is at fault
 

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Discussion Starter #16
yo Joe,
With pump is running, unplug the EEC, if the pump turns off, the EEC is at fault
I don't have to try that to know what will happen.
IF you meant the EEC Relay, pulling it will kill power to the coil side of the fuel pump relay. The field will collapse, and the relay will open.
IF you meant the EEC itself, I already know that circuit 97 from the fuel pump relay, through the self test connector and all the way to the EEC, is NOT shorted to ground, but once it is plugged in to the EEC, it IS shorted to ground. IF that circuit is not grounded, the coil side of the fuel pump relay will have an open circuit, the field will collapse, and the relay will open. If I disconnect from the EEC, the coil side of the fuel pump relay will not be grounded, and the relay will open.

I guess I can check to see which pins on the EEC are ground pins, and then check for continuity between each of them and pin 22 (the grounding output to the fuel pump relay.) If so... that will confirm that the EEC in and of itself is shorted.
 

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Discussion Starter #18
Work! lol... don't you just HATE it when that happens!?

I have a pin out for the EEC, and so I guess I have a little project for myself on Thursday, if work doesn't get in the way. :)
Otherwise I guess this weekend.

Thanks for always being there for me.
joe
 

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you ECC will come out through the cab.
 
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