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Topic: 5.0 EFI Engine Harness Wiring Question (Read 3721 times) previous topic - next topic

5.0 EFI Engine Harness Wiring Question

Hoping someone can take a look at their 86-88 EFI 5.0 engine wiring harness and help me out.  I was working on the driver's side around the starter solenoid where the engine harness meets the chassis harness.  This is the harness I have an issue with:
 

5.0 EFI Engine Harness Wiring Question

Reply #1 –
From the above picture/post, you follow that harness down to where all of the connections are made.  I have mine all separated out at the moment:

5.0 EFI Engine Harness Wiring Question

Reply #2 –
Then, I get to my "issue".  One of the connectors (black, round with a flat side, 4 pin) has four wires coming out of it.  The black wire coming out of this connector goes nowhere ... and it actually looks like somewhat of a clean cut.  I haven't been able to diagnose where this goes.  I haven't found a corresponding black wire in the main part of the harness.  I'm hoping someone can check their harness and let me know where this is supposed to go.

5.0 EFI Engine Harness Wiring Question

Reply #3 –
What are the other colors to that connector? Looks like the plug to the o2 harness to me.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

5.0 EFI Engine Harness Wiring Question

Reply #4 –
Quote
What are the other colors to that connector?


The colors are solid black (broken), green w/ yellow stripe, blue w/ red stripe, and gray w/ yellow stripe.

5.0 EFI Engine Harness Wiring Question

Reply #5 –
Cant tell for sure by wire colors, but I think its the evp connector that goes to the egr.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

5.0 EFI Engine Harness Wiring Question

Reply #6 –
The connector itself connects to the chassis harness in that big hodge podge around the starter solenoid and ignition coil on the driver's side just behind the battery, that isn't really my issue.  The connectors/connections themselves are all good.  I was just poking around and found this loose wire.  I guess what I'm trying to find out is where this wire should go?  Does the wire run out of this connector and to another one or does it just run through the engine harness to the computer?  If so, I didn't locate the other end of it.

5.0 EFI Engine Harness Wiring Question

Reply #7 –
Black wires are grounds, you sometimes find a loose end that is in harness but doesn't connect to anything as some feature isn't there or was deleted...

5.0 EFI Engine Harness Wiring Question

Reply #8 –
Out of 60 wires ran to the computer, maybe 20 actually hook into anything.

At it's newest, you are messing with a 29 year old car. Every time I see smog stuff hooked up, it amazes me.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

5.0 EFI Engine Harness Wiring Question

Reply #9 –
Thanks guys.  I assumed it was a ground being a solid black wire and figured that I'm relatively "ok" since I didn't have any issues prior to finding it (that I'm aware of).  Just curious as to where it goes if it indeed goes anywhere.  I'll have to snoop around the next time I'm in the junk yard to see if I find anything different.

5.0 EFI Engine Harness Wiring Question

Reply #10 –
Is there a corresponding wire in the plug that connects to it and if so would it be easy to chase out?  If you find it going to something then it may clue you in to whether or not it needs to be connected on the other side or if it was for a differently optioned car.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

5.0 EFI Engine Harness Wiring Question

Reply #11 –
what year harness is that?
they like to change wire colors between 86 and 88
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
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5.0 EFI Engine Harness Wiring Question

Reply #12 –
Is it a mustang harness?
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
Join us on Facebook
http://www.facebook.com/home.php?sk=group_137541156293768&ap=1

5.0 EFI Engine Harness Wiring Question

Reply #13 –
Quote
Is there a corresponding wire in the plug that connects to it and if so would it be easy to chase out? If you find it going to something then it may clue you in to whether or not it needs to be connected on the other side or if it was for a differently optioned car.


Yes, there is.  I'll post a pic of the corresponding plug below.  The "broken" black wire on the male connector goes to the black wire with the white stripe in the female connector shown in the pic.

Quote
what year harness is that?
they like to change wire colors between 86 and 88


Quote
Is it a mustang harness?


So ... things get a little "interesting" in this regard.  My car is an 85 and has all of the original chassis wiring (headlights, dash, interior body back to the taillights) ... BUT ... the engine harnesses (small harness on the actual engine that goes to the injectors and a lot of the sensors, plus the main engine harness that this smaller harness plugs into and then goes to the computer) is out of an 86 5.0 EFI Cougar.  I specifically searched for one of these harnesses in salvage yards because it is a direct plug and play into the chassis harness when converting from a TBI 3.8 V6 to an EFI 5.0 V8.  The only wiring modification I had to make was the addition of the mass air.  The 87/88 Tbirb/Cougar engine harness as well as the Mustang harness are very similar, but they would not have been a direct plug and play with the chassis harness.

5.0 EFI Engine Harness Wiring Question

Reply #14 –
This is real long shot here. Early Ford wiring used blue with a red tracer for 12v lighting in the radio and dash lighting. Looking at that harness is it possible that it is for a trailer connector with the blue wire used as a feed to control a lighting relay? Like I said, this is a long shot but I'd try ringing it out with the lights,signals,and key on just to satisfy my curiosity.
84 COUGAR/90 HO, 1.7RRs, performer RPM,700DP, equal length shorties, stainless EXH ,T-5,Hurst pro-billet, KC clutch, 8.8/ 4.10s, line-lok, bla ,bla, bla.
71 COMET/289,351w heads, 12.5 TRWs, 750DP, Liberty TL, 9"/6.00s, 11.9x @112 , bla,bla,bla.

Never shoot your mouth off, unless your brain is loaded! ....I may get older, but I'll never grow up!....If you're not laughing, you're not living!  :laughing: