Bad eec-iv engine computer?
Thread Starter
|
Fleet Mechanic
Joined: Jul 2004
Posts: 1,552
Likes: 0
From: va
Bad eec-iv engine computer?
1987 ford f150 4.9 efi without ac, with no engine light. I tried to do a self test for trouble codes. But touched the volt meter possitive probe ( to battery poss.) to bare metal then heard a load click from the engine computer area, its by the driver brake pedal. Now it doesn't give codes. All the wires at the ecc work excect the signal/return or ground from all the 7 sensors have to much voltage now about 6 volts should have about 2 volts. and the DLC connector self test output have no voltage now. shoulb be less then 1 volt. I found out three vacuum lines were melt thaTS WHY IT DIDN'T START. FIXED THEM AND IT WILL run for three minutes if i spay starting fluid in the throttle body. What are the caunches i fried the engine computer. Relay tested ok to.
Moderator
Joined: Jan 2001
Posts: 56,973
Likes: 2,731
From: Virginia
Bad eec-iv engine computer?
Thread Starter
|
Fleet Mechanic
Joined: Jul 2004
Posts: 1,552
Likes: 0
From: va
test relays
On mine it has two relays on the ecc power relay it has four wires. Red power, blk ground, yellow power ecc and, wht-t blue ignition. Key on all have 12 volts except ground. Do I need to test the fuel pump relay to?
Thread Starter
|
Fleet Mechanic
Joined: Jul 2004
Posts: 1,552
Likes: 0
From: va
bad ecc-iv
Thats what I thought. Can i test the ECC off the truck? Also I thought i may have a signal return/ground short so i cut the signal return/ ground wire at the engine computer. Then tested for voltage it now has no voltage at the ecc, this must be normal though. Why no voltage it's not really a ground its more of a return??? Then I tried to read codes off the cut sign return wire at the ecc but no codes.
Will it start with a new ecc if my plugs have carbon on them all. Should I bother to clean them off or just buy new ones. Rich plugs were caused by melted vacuum lines, its now repaired.
Thanks mike
Will it start with a new ecc if my plugs have carbon on them all. Should I bother to clean them off or just buy new ones. Rich plugs were caused by melted vacuum lines, its now repaired.
Thanks mike
Thread Starter
|
Fleet Mechanic
Joined: Jul 2004
Posts: 1,552
Likes: 0
From: va
Getting codes with a volt meter
I was just woundering when I tried to do a self test for codes three different days it was always pegged to the right. Why?? I tried a bulb instead and it stayed on all the time to. I did not press in the clutch. This was before the load click and no more movement of meter needle, or light from bulb. I thought I did just like in the Haines Manual. 87 f150 4.9 efi 4 speed
Moderator
Joined: Jan 2001
Posts: 56,973
Likes: 2,731
From: Virginia
Trending Topics
Thread Starter
|
Fleet Mechanic
Joined: Jul 2004
Posts: 1,552
Likes: 0
From: va
Reading codes
Thanks, I was using fordfuelinjection.com but I like your site better. I didn't know it had to be in neutral. Did I check my relay correctly. I left the relay in. Back probed three wire for 12 volts. One was ground. The volt meter went to battery ground. Does this tell me that 12 volts is going through the relay?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Moderator
Joined: Jan 2001
Posts: 56,973
Likes: 2,731
From: Virginia
The eec relay coil wire is white/lightblue.
Ground is black.
Power coming into the relay contacts is yellow.
Power leaving the relay contacts to feed the computer system is red. It should also have a blue fusible link on the red wire. Check for voltage after the fusible link to make sure it's not burnt out.
Also check pin 1 of the computer. It should have a yellow wire going to it with 12 volts on it all the time.
When the EEC relay is pulled in, pins 57 and 37 shouldhave 12 volts.
Pin 20 is ground
Just remember, on most of your computer solenoids, fuel pump relay coil, fuel injectors, etc., the red wires feed 12 volts to these all the time, and the computer grounds the other side to make it activate.
Ground is black.
Power coming into the relay contacts is yellow.
Power leaving the relay contacts to feed the computer system is red. It should also have a blue fusible link on the red wire. Check for voltage after the fusible link to make sure it's not burnt out.
Also check pin 1 of the computer. It should have a yellow wire going to it with 12 volts on it all the time.
When the EEC relay is pulled in, pins 57 and 37 shouldhave 12 volts.
Pin 20 is ground
Just remember, on most of your computer solenoids, fuel pump relay coil, fuel injectors, etc., the red wires feed 12 volts to these all the time, and the computer grounds the other side to make it activate.
Thread Starter
|
Fleet Mechanic
Joined: Jul 2004
Posts: 1,552
Likes: 0
From: va
Eec Relay
Originally Posted by Franklin2
The eec relay coil wire is white/lightblue.
Ground is black.
Power coming into the relay contacts is yellow.
Power leaving the relay contacts to feed the computer system is red. It should also have a blue fusible link on the red wire. Check for voltage after the fusible link to make sure it's not burnt out.
Also check pin 1 of the computer. It should have a yellow wire going to it with 12 volts on it all the time.
When the EEC relay is pulled in, pins 57 and 37 shouldhave 12 volts.
Pin 20 is ground
Just remember, on most of your computer solenoids, fuel pump relay coil, fuel injectors, etc., the red wires feed 12 volts to these all the time, and the computer grounds the other side to make it activate.
Ground is black.
Power coming into the relay contacts is yellow.
Power leaving the relay contacts to feed the computer system is red. It should also have a blue fusible link on the red wire. Check for voltage after the fusible link to make sure it's not burnt out.
Also check pin 1 of the computer. It should have a yellow wire going to it with 12 volts on it all the time.
When the EEC relay is pulled in, pins 57 and 37 shouldhave 12 volts.
Pin 20 is ground
Just remember, on most of your computer solenoids, fuel pump relay coil, fuel injectors, etc., the red wires feed 12 volts to these all the time, and the computer grounds the other side to make it activate.
Moderator
Joined: Jan 2001
Posts: 56,973
Likes: 2,731
From: Virginia
If you have 12 volts on the red wire, the relay is working.
Putting the black meter lead on the battery negative is ok, but if you suspect a grounding problem, then you need to put the black meter lead on the suspect spot. For instance, the computer pins. You can put the black meter lead on the sheetmetal part of the truck, and read pins 57 and 37, and get 12 volts. But if you want to check to make sure your ground to the computer is ok, then take these readings with the black meter lead on pin 20. Even though you have 12 volts on the computer, if it does not have a good ground, it will not work. If the wire to pin 20 is broken somewhere, and you put your meter between pin 20 and one of the 12 volt pins, your meter will not read 12 volts as before. Keep this in mind everywhere you check for voltage.
Putting the black meter lead on the battery negative is ok, but if you suspect a grounding problem, then you need to put the black meter lead on the suspect spot. For instance, the computer pins. You can put the black meter lead on the sheetmetal part of the truck, and read pins 57 and 37, and get 12 volts. But if you want to check to make sure your ground to the computer is ok, then take these readings with the black meter lead on pin 20. Even though you have 12 volts on the computer, if it does not have a good ground, it will not work. If the wire to pin 20 is broken somewhere, and you put your meter between pin 20 and one of the 12 volt pins, your meter will not read 12 volts as before. Keep this in mind everywhere you check for voltage.
Thread
Thread Starter
Forum
Replies
Last Post
cricketo99
1987 - 1996 F150 & Larger F-Series Trucks
18
Jan 31, 2024 04:15 AM
fordpride
1999 - 2003 7.3L Power Stroke Diesel
15
May 23, 2016 01:00 PM
Mustangking1
1973 - 1979 F-100 & Larger F-Series Trucks
12
Oct 8, 2015 05:09 AM
