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EEC trouble code help

suckerpunched

Sr. Member
Joined
Aug 24, 2006
Messages
882
My son was driving his Bronco yesterday, It has been running great with no issues for a couple thousand miles. 100+ miles on it just yesterday. started to run bad and died at a stoplight. started back up but ran bad with lack of power and died at next light too. Ran like it was out of gas. He called me to help him. when I got there it would start and run fine fuel gauge showed 3/4 full. I thought maybe the gauge went bad and maybe it was really running out so I put 5 gallons in it. Gauge went to full and he was able to drive home 15 miles with no issues. Checked fuel pressure today and it is normal, 32 psi, Ran codes and got all the normal codes for the missing emissions stuff and also code 95 (fuel pump secondary circuit failure, EEC senses infinite resistance to ground from the fuel pump on the fuel pump monitor circuit) and 96 fuel pump secondary circuit failure, EEC did not sense battery voltage on the fuel pump on the fuel pump monitor circuit)
what could be causing this? I am guessing FP relay, wiring, or Fuel pump itself. maybe inertia switch. I an running an in-tank pump. what do you guys think?
 

ransil

Bronco Guru
Joined
Sep 6, 2003
Messages
8,122
My son was driving his Bronco yesterday, It has been running great with no issues for a couple thousand miles. 100+ miles on it just yesterday. started to run bad and died at a stoplight. started back up but ran bad with lack of power and died at next light too. Ran like it was out of gas. He called me to help him. when I got there it would start and run fine fuel gauge showed 3/4 full. I thought maybe the gauge went bad and maybe it was really running out so I put 5 gallons in it. Gauge went to full and he was able to drive home 15 miles with no issues. Checked fuel pressure today and it is normal, 32 psi, Ran codes and got all the normal codes for the missing emissions stuff and also code 95 (fuel pump secondary circuit failure, EEC senses infinite resistance to ground from the fuel pump on the fuel pump monitor circuit) and 96 fuel pump secondary circuit failure, EEC did not sense battery voltage on the fuel pump on the fuel pump monitor circuit)
what could be causing this? I am guessing FP relay, wiring, or Fuel pump itself. maybe inertia switch. I an running an in-tank pump. what do you guys think?


cheap and easy is to change the relay, if that does not work when its dead next time break out the meter and check voltage along the path from computer to pump.
 
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suckerpunched

suckerpunched

Sr. Member
Joined
Aug 24, 2006
Messages
882
for clarification, what is considered to be the secondary circuit? from the relay to the pump, or from the power distribution box to the pump? and primary would be? ecm to relay, or?

also if something is wrong after the inertia switch, which is where the FPM signal back to the ECM comes from, can the ECM detect this? for example, if I unplug the fuel pump at the tank, does the ECM have a way to know the power and ground to the pump are open?
 

904Bronco

Contributor
Bronco Guru
Joined
Sep 28, 2004
Messages
5,749
Loc.
San Martin, CA
for clarification, what is considered to be the secondary circuit? from the relay to the pump, or from the power distribution box to the pump? and primary would be? ecm to relay, or?

also if something is wrong after the inertia switch, which is where the FPM signal back to the ECM comes from, can the ECM detect this? for example, if I unplug the fuel pump at the tank, does the ECM have a way to know the power and ground to the pump are open?

The ECU closes the relay for power to the pump by sending a ground signal... That power goes through the inertia switch and then to the pump, The ECU does not monitor that...
 
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suckerpunched

suckerpunched

Sr. Member
Joined
Aug 24, 2006
Messages
882
The ECU closes the relay for power to the pump by sending a ground signal... That power goes through the inertia switch and then to the pump, The ECU does not monitor that...

OK thanks, that helps narrow it down quite a bit. I changed the relay today, will just have to drive it awhile and see what happens
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
Heck yeah, so it can make it to the Roundup on the 6th!;);D

I forget, but is 32 normal for idle on your engine? Is this all Ford EFI stuff? I thought it was nearer to 40 at idle?
Been awhile though, so sorry if I'm mixing my systems up.

Paul
 

ransil

Bronco Guru
Joined
Sep 6, 2003
Messages
8,122
Heck yeah, so it can make it to the Roundup on the 6th!;);D

I forget, but is 32 normal for idle on your engine? Is this all Ford EFI stuff? I thought it was nearer to 40 at idle?
Been awhile though, so sorry if I'm mixing my systems up.

Paul

32 is normal at idle as the regulator has full vacuum applied, with throttle input vacuum drops causing the fuel pressure to go higher.

from experience Ford EFI will idle ok at around 24 psi but break up under load at that psi .
 
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suckerpunched

suckerpunched

Sr. Member
Joined
Aug 24, 2006
Messages
882
Heck yeah, so it can make it to the Roundup on the 6th!;);D

I forget, but is 32 normal for idle on your engine? Is this all Ford EFI stuff? I thought it was nearer to 40 at idle?
Been awhile though, so sorry if I'm mixing my systems up.

Paul

I don't know yet if I will be at the roundup, but would like to go.
 
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