Wiring ?
Thread Starter
|
Freshman User
Joined: Sep 2012
Posts: 40
Likes: 0
Wiring ?
I have a 1985 F150 w/5.0 MPFI and am having wiring problems, specifically a ground problem.
1) Where to locate an accurate wiring diagram. Mitchell's and All-Data are a no go. All-Data is hard to navigate and primitive. Mitchchell's diagram for 85 F150 5.0 has several wrong color codes on diagnostic connection and EEC. Ex: #1 wire to EEC is actually yellow not violet (per Mitchell's). None of the wire color codes on diagnostic connector (per Mitchell's) match my vehicle. Mitchell's wiring diagram for 86 F150 comes closer, but still not dead on.
2) Mitchell's has no table listing physical ground locations. These things can be located anywhere. Anyone know where they are?
I've found ground wire to body at L.H. headlamp, ground lead from battery neg. to wiring harness, and battery to engine ground (at battery neg. terminal)
Where does battery neg. lead that goes into wiring harness go? Is there a common ground for EEC and if so where?
Getting really frustrated. Next step is taking the truck apart.
1) Where to locate an accurate wiring diagram. Mitchell's and All-Data are a no go. All-Data is hard to navigate and primitive. Mitchchell's diagram for 85 F150 5.0 has several wrong color codes on diagnostic connection and EEC. Ex: #1 wire to EEC is actually yellow not violet (per Mitchell's). None of the wire color codes on diagnostic connector (per Mitchell's) match my vehicle. Mitchell's wiring diagram for 86 F150 comes closer, but still not dead on.
2) Mitchell's has no table listing physical ground locations. These things can be located anywhere. Anyone know where they are?
I've found ground wire to body at L.H. headlamp, ground lead from battery neg. to wiring harness, and battery to engine ground (at battery neg. terminal)
Where does battery neg. lead that goes into wiring harness go? Is there a common ground for EEC and if so where?
Getting really frustrated. Next step is taking the truck apart.
Moderator
Joined: Jan 2001
Posts: 56,949
Likes: 2,718
From: Virginia
I believe there is a ground from the battery to the EEC harness, and it has a connector in it that likes to corrode.
I see you are using a lot of third party wiring diagrams. Why not get the Ford diagrams? They have all the info you need. You can buy them new if they are in stock at http://www.helminc.com. You might be able to find them used on ebay.
I see you are using a lot of third party wiring diagrams. Why not get the Ford diagrams? They have all the info you need. You can buy them new if they are in stock at http://www.helminc.com. You might be able to find them used on ebay.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Here is a Ford Diagram for 302 with EEC-IV TFI-IV with EFI.
http://i447.photobucket.com/albums/q...VEEC-IV50L.jpg
http://i447.photobucket.com/albums/q...VEEC-IV50L.jpg
Moderator
Joined: Jan 2001
Posts: 56,949
Likes: 2,718
From: Virginia
That's interesting. The company that is the authorized publisher for Ford, Honda, GM, etc. is gone. They are either having trouble with their site, or possibly something more serious is happening behind the scenes.
Thread Starter
|
Freshman User
Joined: Sep 2012
Posts: 40
Likes: 0
On wiring diagrams--color code on diagrams don't match my truck. Color codes on the following are incorrect.
1) diagnostic test connector
2) TFI connection
3) Fuel pump relay
Did they use different wiring harnesses for different assembly plants? Can't find wiring diagram that matches. Impossible to trouble-shoot system.
Need info on where grounds are physically located.
1) diagnostic test connector
2) TFI connection
3) Fuel pump relay
Did they use different wiring harnesses for different assembly plants? Can't find wiring diagram that matches. Impossible to trouble-shoot system.
Need info on where grounds are physically located.
Trending Topics
Thread Starter
|
Freshman User
Joined: Sep 2012
Posts: 40
Likes: 0
Is there a possibility that this could be a truck manufactured in Canada? How would I find that out?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
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
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Moderator
Joined: Jan 2001
Posts: 56,949
Likes: 2,718
From: Virginia
On the diagnostic connector my diagram shows;
black/white as a common power wire
tan/red goes to the computer
tan/lightgreen is the fuel pump wire
white/red is the single wire to trigger the test
black/white as a common power wire
tan/red goes to the computer
tan/lightgreen is the fuel pump wire
white/red is the single wire to trigger the test
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
On wiring diagrams--color code on diagrams don't match my truck. Color codes on the following are incorrect.
1) diagnostic test connector
2) TFI connection
3) Fuel pump relay
Did they use different wiring harnesses for different assembly plants? Can't find wiring diagram that matches. Impossible to trouble-shoot system.
Need info on where grounds are physically located.
1) diagnostic test connector
2) TFI connection
3) Fuel pump relay
Did they use different wiring harnesses for different assembly plants? Can't find wiring diagram that matches. Impossible to trouble-shoot system.
Need info on where grounds are physically located.
There have been cases where wire colors have been off on certain trucks to the official diagrams.
My Ford Diagram above (posted earlier) matches what Franklin2 is saying here.
Originally Posted by Franklin2
On the diagnostic connector my diagram shows;
black/white as a common power wire
tan/red goes to the computer
tan/lightgreen is the fuel pump wire
white/red is the single wire to trigger the test
Originally Posted by Hutch246
Is there a possibility that this could be a truck manufactured in Canada? How would I find that out?
If USA, 1FT
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
Likes: 11
From: Exmore, VA
One of the real problems with the 85-86 5.0L EFI is the entire EFI harness grounds at a two pin connector by the battery that is part on the original ground cable. It corrodes and you lose the ground. The wires in the harness are black with a light green stripe. I would find them where they plug in and put a ring terminal (solder it) on each and connect them directly to the battery negative terminal. This is from my 1986 EVTM. I chased a ground issue on one of these for a week before determining it was that plug, it is C101 on the diagram.
Moderator
Joined: Nov 2007
Posts: 22,415
Likes: 92
From: Denver Metro Area, CO
I'd try again tomorrow.
Thread Starter
|
Freshman User
Joined: Sep 2012
Posts: 40
Likes: 0
One of the real problems with the 85-86 5.0L EFI is the entire EFI harness grounds at a two pin connector by the battery that is part on the original ground cable. It corrodes and you lose the ground. The wires in the harness are black with a light green stripe. I would find them where they plug in and put a ring terminal (solder it) on each and connect them directly to the battery negative terminal. This is from my 1986 EVTM. I chased a ground issue on one of these for a week before determining it was that plug, it is C101 on the diagram.
More info on grounds. There is one at the rear of block near fuel rail connector, one going to a bolt on wiper motor, and a third that has a connector to a wire that goes into the wiring harness. This last one has a connector that isn't water proof and will likely corrode. Cleaned and reassembled with Di-electric grease.
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
Likes: 11
From: Exmore, VA
It is two wires with a rectangular plug/socket near the battery negative terminal. A splice will do nicely, just be sure it won't corrode from the battery fumes. The ground for the EEC was what you had asked about, that was the one I addressed. The grounds on these are pretty bad, the entire front harness other than the EEC grounds inside the cab on the firewall, The engine to body ground wire is the one to the wiper motor stud. I no longer have the 86 EVTM, I gave it to Archion.
