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- Joined
- Nov 9, 2008
- Messages
- 200
- Reaction score
- 0
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- Location
- Pitt Meadows
- Vehicle Year
- 1988
- Make / Model
- BroncoII
- Engine Size
- 2.9
- Transmission
- Automatic
Original poster:HndMeDnBroncoII
Difficulty:2 out of 10
Time to complete:Half an hour.
Brief explanation:This guide will aid you to check operation of your
fuel pump and engine control relays{eec}
My vehicle is an 88 BroncoII 4x4 with a 2.9v6.
This guide will apply to multiple years of Fords.
Symptoms:Engine feels slugish,lack of power,rough idle and poor fuel mileage.
Tools needed:dvom meter
5" jumper wire
--------------------------------------------------------------------------
Step 1A:Select the 12 volt function on your dvom.For reference check the
battery voltage with the ignition off.My battery was 11.9 volts.
1B:Check starter relay for voltage the wire from the battery should
read the same as the battery if not inspect the wire and connections.
check the fusible links on the same post for any visible damage.
The other post supplies power to the starter,there should be no
voltage with the ignition key off.
Engine control relay description.
Between the passenger fender and the air box is your relays.
The engine control relay has five wires,
yellow x2
ne from the starter relay,the other to the ecu.
The yellow is always live battery voltage.
red:supplies power to the fuel injectors,fuel pump relay and
several other key systems.
red-lt green:Comes from the ignition to energize the relay.
black-lt green:Is common ground.
1C:With ignition off measure voltage from yellow to batt ground,
voltage should match the battery reading.If the reading is less
check the fusible link and starter relay connection.
The other two wires should have no voltage.If there is voltage
present the relay is bad.
2A:With the engine running,all three wires should match battery
voltage.If not the relay is bad.
Side note:The contacts inside the relay do get dirty and corroded,
i have found that the relay operates fine in the cold
and dry but moisture would kill it.
I also found that the red wire would read 1.2 volts
during a no start condition.
The fuel pump relay has five wires.
yellow:from the fusible link at the starter relay.Always live.
red:from the eec relay.
tan-lt green:from the ecu.
orange-lt blue x2 :to the inertia switch and the ecu.
3A:With the engine running,
the red wire should match battery voltage,if not check the
connection to the eec relay.
the yellow should match battery voltage,if not check the
connection to the starter relay.
the orange should match battery voltage,if no recheck the
yellow and red.
the tan is a variable voltage wire controlled by the ecu,
depending on what the engine requires Be careful diagnosing.
By no means is this a sure fire fix but i'm sure it will shed alot of light
for some of our members.I even had to return a relay two months old
because moisture got at it.It you have original relays or they are more
than a couple of years old it might just be easier to replace them.LoL
As always though,double check your manuals.
Difficulty:2 out of 10
Time to complete:Half an hour.
Brief explanation:This guide will aid you to check operation of your
fuel pump and engine control relays{eec}
My vehicle is an 88 BroncoII 4x4 with a 2.9v6.
This guide will apply to multiple years of Fords.
Symptoms:Engine feels slugish,lack of power,rough idle and poor fuel mileage.
Tools needed:dvom meter
5" jumper wire
--------------------------------------------------------------------------
Step 1A:Select the 12 volt function on your dvom.For reference check the
battery voltage with the ignition off.My battery was 11.9 volts.
1B:Check starter relay for voltage the wire from the battery should
read the same as the battery if not inspect the wire and connections.
check the fusible links on the same post for any visible damage.
The other post supplies power to the starter,there should be no
voltage with the ignition key off.
Engine control relay description.
Between the passenger fender and the air box is your relays.
The engine control relay has five wires,
yellow x2
ne from the starter relay,the other to the ecu.The yellow is always live battery voltage.
red:supplies power to the fuel injectors,fuel pump relay and
several other key systems.
red-lt green:Comes from the ignition to energize the relay.
black-lt green:Is common ground.
1C:With ignition off measure voltage from yellow to batt ground,
voltage should match the battery reading.If the reading is less
check the fusible link and starter relay connection.
The other two wires should have no voltage.If there is voltage
present the relay is bad.
2A:With the engine running,all three wires should match battery
voltage.If not the relay is bad.
Side note:The contacts inside the relay do get dirty and corroded,
i have found that the relay operates fine in the cold
and dry but moisture would kill it.
I also found that the red wire would read 1.2 volts
during a no start condition.
The fuel pump relay has five wires.
yellow:from the fusible link at the starter relay.Always live.
red:from the eec relay.
tan-lt green:from the ecu.
orange-lt blue x2 :to the inertia switch and the ecu.
3A:With the engine running,
the red wire should match battery voltage,if not check the
connection to the eec relay.
the yellow should match battery voltage,if not check the
connection to the starter relay.
the orange should match battery voltage,if no recheck the
yellow and red.
the tan is a variable voltage wire controlled by the ecu,
depending on what the engine requires Be careful diagnosing.
By no means is this a sure fire fix but i'm sure it will shed alot of light
for some of our members.I even had to return a relay two months old
because moisture got at it.It you have original relays or they are more
than a couple of years old it might just be easier to replace them.LoL
As always though,double check your manuals.
