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Discussion Starter #1
Hey Corral!

I have been stuck on this wiring issue for quite some time now and I am reaching out to anyone in the LA area (I live in North Hollywood) who can come by and help me out with a wiring problem.

Here is the basic rundown:
My car is a 1990 4 cylinder conversion. I swapped my engine and injector harness over and it plugged in and ran for a while. I had a wiring issue that required me to remove those harnesses (engine and injector) and replace them. I bought a harness from a member on here and got everything installed, with a few connectors that had no mate. I didn't see this as an issue because I had deleted items from my engine anyway so I just thought they went to those (airbag and such). It plugs up just fine except afterwards I found out that the harness I had was from a 91 I believe and I guess the wiring was all jacked around with from the dealer.
I now have an issue where the fuel pump wont prime and the OBD port won't read codes. Everything else works as far as I can tell. I jumped the fuel pump to make sure it still worked and it does and I even cranked up the car and it ran for about 3 seconds before shutting off (no fuel from the pump).

Basically I need someone who is good with wiring and can help me figure this out. Send me a PM if you can help and I can work around your schedule as I work from home. Thanks in advance and beers are on me.

Chris
 

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there is really too little info on this, and sounds like unknown harness is being used.

you may consider, finding a entire harness out of a wreck that has not been messed with.

otherwise it will take quite a long time, to ensure the proper circuits are complete.
 

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Discussion Starter #3
Indy,

Thanks for the reply. You are always on it with the electrical stuff. The harness is from a 91 and I'll I got is time with thing anyway, so it's no big deal to me, but it's your time I am concerned with. FWIW I don't think the harness is too far off as everything else pretty much works as far as I know. Maybe just a little tweaking her and there. I just need someone with the knowledge is all. Can you help?


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I am in the process of rebuildling the harness in my 1989 for a wire tuck that involves making most of the harness run under the dash instead of through the engine compartment. I have become VERY familiar with the harness and routing by doing this, and I have one of the COMPLETE old school Chilton's Total AutoCare books to boot (these have the full 22 page wiring diagram for each individual model year). I have also removed my emissions wiring (because I don't need that crap!) not by cutting it out of the harness, but by unpinning it from the connectors one by one. I could put it all back if I had to.

It gets even better...even though I live in SC, I may be traveling to Los Angeles to work at the Chevron El Segundo refinery in the next week (waiting on my background check to go through.)

Let me know if you think I can help.
 

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Indy,

Thanks for the reply. You are always on it with the electrical stuff. The harness is from a 91 and I'll I got is time with thing anyway, so it's no big deal to me, but it's your time I am concerned with. FWIW I don't think the harness is too far off as everything else pretty much works as far as I know. Maybe just a little tweaking her and there. I just need someone with the knowledge is all. Can you help?


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going to be at a conference, next couple of days, so will not have much time to answer

but, list exactly what you know you have, and i'll have a look at compatibilty
 

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Discussion Starter #6
@stu11926 - Wow! That's great and yes I would totally take you up on the offer. Good luck with the background check and let me know when you are in town and we can knock this out hopefully.
@indy2000 - Here is what I have:
1990 4 cylinder dash and body harness
1990/91 V8 Engine harness (it has the white plugs for the air bags)
1990/91 V8 Injector harness

Everything plugs up with the exception of the Air Bags as I deleted them and a few other random plugs, but otherwise it all plugs up. I can crank the car and when I jump the FP I can get it to start. I called the Ford Racing Tech line and spoke with the wiring guru there and he said to check the following:
- Check Pin 37 and 57 at the computer and make sure I had power with the key on, which I did.
- Check the pink/black wire at the FP relay for power, which I did not. Not even when the key is on.
- Check for power (2-3 seconds) at the FP relay (dark green/yellow wire) when the key is turned to the on position for the FP prime, which I had constant power.

I know it seems like the pink/black and green/yellow wires are crossed somewhere, but I don't see how that's possible because I didn't cut the harness or re-pin anything that goes to the FP. The only thing I can think of is a mismatched harness that I will have to re-pin.

Let me know if you need anything else and thanks for your help.
 

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even if the plug connects, the pin arrangement has changed.

there are many changes over the years...

I don't believe the dash and engine harness, match up, from the 2.3 to 5.0 engines

like I said the plugs might be there but the PINS have to be in the correct places.

this is where you need diagrams of both harnesses.
 

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306Guy;16876658 [USER=22216 said:
@indy2000[/USER] - Here is what I have:
1990 4 cylinder dash and body harness
1990/91 V8 Engine harness (it has the white plugs for the air bags)
1990/91 V8 Injector harness


- Check the pink/black wire at the FP relay for power, which I did not. Not even when the key is on.
- Check for power (2-3 seconds) at the FP relay (dark green/yellow wire) when the key is turned to the on position for the FP prime, which I had constant power.

I know it seems like the pink/black and green/yellow wires are crossed somewhere, but I don't see how that's possible because I didn't cut the harness or re-pin anything that goes to the FP. The only thing I can think of is a mismatched harness that I will have to re-pin.

Let me know if you need anything else and thanks for your help.
Looking at my wiring diagrams, I think you're on the right track here, but are you ABSOLUTELY CERTAIN that you have a 1990 4 cyl body harness?

The diagram for 1990 only shows one set of wiring (for both 2.3L and 5.0L at the fuel pump relay. The wire colors are listed as T/LG, R/BK, PK/BK, PK/BK, and O/LB.

The diagram for 1991 shows different wiring at the fuel pump relay for the 2.3L and 5.0L, and they are definitely pinned differently.

The 2.3L has LB/O, R, DG/Y, and PK/BK.

The 5.0L has T/LG, R/BK, PK/BK, and O/Y. (I think...the print is VERY small on the 1991 diagram, and harder to read than the 89-90 versions.)
 

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Discussion Starter #9
The dash harness IS from a 1990 4 cylinder because that's what the car is and I didn't change that part of it.

The body harness worked with the 89 GT harness I had in the car before so I am not sure why it wouldn't work with the harness I have in there now.

I understand the pins may be off on a few things, but for them to be completely off would be pretty ####ty.

Here is a pic of my FP relay located under the drivers seat. The cut wire is actually reconnected, so no worries with that one.

Let me know what you think. Thanks.

ImageUploadedByAG Free1456522168.116290.jpg


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Discussion Starter #10
Also, when I chase the fuse link D (org/lt blue) which apparently powers the FP relay according to my diagram (even though that is not the color that I have on my relay) it leads to this box (under the steering column area), but that wire had no power and in fact only the red and gray/yellow wires have power. Any ideas. I also attached the wiring diagram I am using (Chilton - 89/90 5.0 engine).
ImageUploadedByAG Free1456556484.263838.jpg ImageUploadedByAG Free1456556524.837725.jpg


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89 and 90 harnesses are NOT the same pinned.

also the 89 and 90 fuel pump circuits are different

89 inertia switch breaks control wire,

90 breaks the load wire.

What is your plan to ID and correct these differences?
 

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Is it possible you are using a pre-'89 (or pre-88 for us CA guys, although even then they are diff from '89) wiring harness w/o a MAF and the MAF wires are spliced in wrong? I don't mean that to sound antagonistic, just trying to think of stuff but indy, while a douchebag, is usually right - have you ID'd the harness at all?

Also prob a long shot, but take the "salt and pepper shakers" behind the intake manifold and give them a good clean with electronics cleaner and use a small pin to spread the pins on the male side so they fit more securely in the female side, as well as making sure you have excellent grounding points everywhere from the engine to body and body to batt, and even engine to batt directly.
 

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Discussion Starter #13
I did the salt and pepper thing already and as far as ID'ing the harness I really wouldn't know where to start. Is there a tell-tell set of wires that would inform which harness I have? I can look for that. I did mention that this new engine harness had the white plug connectors for air bag I believe. Does that help?

The MAF wires were all there and stock, so I don't think that's the issue.

I do know that the dash is from the 90 2.3 engine because I kept it in the car with the swap. The guy that sold me the other wires (engine/injector) said they were from the same car, but I can't find his PM, so I'll go back through my stuff and see what I can find to help ID the harness.


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Discussion Starter #15
Thank for the Veryuseful link. I have been using it, but still need help.


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A 1991 computer harness will not plug into a 1990 dash harness as they are different connectors (87-90 use a gray AND black connector for dash connection, while 1991-93 uses a single redish brown connector)
Injector harnesses are the same from 86-93
Don't rule out a bad computer as well.
 

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Discussion Starter #17
To clarify a few things:

1) Dash harness is a 90 4 cyl
2) Engine harness is 90 v8 (has the white plugs next to the MAF wiring)
3) Injector harness is 90 v8
4) Circuit (red wire from ECU relay to Inertia switch) is good and tested with a tone generator
5) Circuit (red/black wire from inertia switch to FP relay) is good and tested with a tone generator
6) FP Relay 12v source (green/yellow) is good with key on and off
7) FP relay red/black wire has 0v with key on and off
8) FP relay pink/black wire has 0v with key on and off
9) FP Relay tan/green wire has 0v with key on and off
10) When I jump the 12v (green/yellow) FP relay wire to the pink/black the FP primes
11) The ECU test plug (where you read the codes) does not work, probably because the tan/green wire has 0v
12) When I ground pin 22 at the ECU with the key on the FP primes
13) I replaced the FP relay and have the same issue
14) When I jump the wires at the FP relay I can start the car and it will run until I remove the jumper, then it will die out when the fuel is gone
15) Booster area connectors are gray and black, but in the gray plug there are 5 wires that go in and 8 that come out (or the other way around) and the black one also has something like that going on, I need to check.

OK. I think that's everything for now, dig in please and let me know what you got. Thanks guys!!
 

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that does not clarify

best I see in my diagrams...........

can you tell me if your inertia switch is in series with the FP relay coil or the pump line/load

there was a change from '89 to '91

also your green/yellow hot all the time is a left over from the 2.3L,,,,,,,which makes no sense......

once you answer the inertia switch.......we can try to id the rest of the relay wires.


this will be a crap shoot.
 

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Discussion Starter #19
A crap shoot is the best I got right now.

The inertia switch as far as I can tell is unlike with the FP relay. The red wire goes from the ECU relay to the inertia switch and the red/black goes from the inertia switch to the FP relay. Is that what you mean?

The 12v green/yellow that comes off the FP relay goes into the harness where the drivers side kick panel is and connects with the orange/light blue wire, which is the one that comes from the fuse link I guess.

Another thing is that there is this TRW box that is for the 4 cylinder AC fan controller and when I ground pin 22 (tan/green) it clicks. In fact whenever I turn the key to the run position it clicks. There is also the orange/light blue wire going to it as well as others.

Here are the colors and a pic.
Red/orange
Orange/black
Orange/lt blue
Black
Brown/white
Pink/lt blue
Gray/yellow
Black
ImageUploadedByAG Free1458665788.664514.jpg


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cannot open that pic.

If that is the integrated control module, I suggest you stop

get the proper wiring diagram...I only have 89 and 91

only a few wires are making sense....

You do have the inertia switch on the control side, which is similar to the 89 not the 91, but you are missing the ecm ground side switch to energize the FP relay coil.?????
 
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