Help with Frankenstien 5.0, harness related.

[Fett]

Ok, the quick background....as I know it.

It was originally an 88, 2.3L, not 100% sure what tranny. Now it is a 5.0 speed density, T5. I wanted to convert it over to mass-air, so I got a PCM, map sensor, MAF, tubing, and complete engine harness out of a 91/92 GT.

When I took off the airbox, I noticed that the harness that was in the car was mass-air, even though the engine was speed density. I plugged in the MAF, "new" PCM, and MAP, turned it on and she ran fine. A slight surge, but I think that has more to do with the vac lines...or lack thereof.

I was going to stop there...but the harness that was in the car had some questionable wires, some split insulators...it was pretty haggard. So I figured I had a good harness out of the same car as the MAFS, MAP, and PCM. Why not change it as well? At least I would know where that all came from....as I continue converting everything to as close to stock as possible.

With the new harness the fuel pump was getting no power. You couldn't hear it prime when you turned the ignition, and it wouldn't start. It has spark and has gas in the tank, but for some reason the pump wasn't working.

The only different connectors on the harness was for the airbags, which my 88 doesn't have. Near the MAFS connector was two connectors that would go to crash sensors, and near the PCM connector there is another grey connector, I assume for the airbag module. The only other difference we could see is the wires leading to the green connector that runs near the PCM. In the car the harness has a ground, PCM connector, grey connector (airbag), eec relay, and a green connector.

The lines going into the green connector on the harness side don't match the ones going to the green connector on the interior side. We assume there is a ground or something not right.

So basically, what could be in that harness, that is different from an 88 and a 92, that would have to do with the fuel pump?

Any thoughts.....OTHER than I should have started with a different car?

 

[crunchie12268]

eeeeewwww that is a mess..... good luck

 

[Fett]

Yea, it is quite the adventure. I chose to do this though, I figure I have no clue what is in the car...hell, I don't know what years it really is. So I figure better to be safe than sorry, and change as much as I can to "known good" parts. That way when I am done doing little projects like this, I will at least know what everything in the car really is, and what year everything is.

The only thing stumping me at this point is that connector. And what in that connector could possibly stop the fuel pump from working.

 

[jrichker]

Copied From bbunt302

Just for reference, here's a list of all the compatible years:

89 harness should work for 86-89 as long as you're using mass air.
90 harness will only work in a 90. (B/c of air bags and dual dash connectors)
91 through early 92 harnesses should be compatible (single dash connector, fuel pump relay under driver's seat)
Late 92 through 93 harnesses should be compatible (single dash connector, fuel pump relay under the hood)

Computers from 89-92 are all the same. Look for the A9L sticker on the back cover for a 5 speed that matches your requirements. Example: E9ZF 12A650 AA" with the A9L code.

Wiring links:
http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model cars

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model cars.

 

[Fett]

About the dash harness, how does that come into play? The engine harness only connects to driveability sensors and the PCM, no? Or is that what the green connector next to the PCM is for? Because that is the only connector that is giving me problems....at least I think it is the only one.

When you run the engine harness into the firewall, you have the PCM connector, a ground wire, the eec relay, and a green connector. In the case with my new harness, it also has a grey connector I assumed went to the airbag module, which I don't have. I didn't see a problem not connecting that to anything, because the two grey connectors in the engine compartment, off of that harness, that normally go to crash sensors I didn't plug in. So I figures I need not worry about those. Which left me with the green connector being different.. Or better yet, the wires don't all match up from one side of the green connector to the other.

 

[jrichker]

Time to visit the 2 links I posted and see what the differences really are.

 

[Fett]

I did, and I am going to print them out and see what I can figure out.

I would find it hard to believe that with all the swapping and crossing over of parts from different years, I am the only person to every experience this problem. So if anybody has gone through this before, any advice would help.

 

[frddriver]

I was helping a friend convert his 90 2.3 to a 5.0, and we had the same problem, we were using a engine harness from a 89 5.0, we were scratching our heads for days trying to figure out why everything seemed fine except for NO FUEL, finally we gave up and he decided just to with a carb setup, then one day i was going through some old issues of 5.0 magazine and discovered info on 2.3 to 5.0 swaps, to sum it up the info jrichker is giving you is right on, your best bet is to just change the whole harness, engine, dash everything from the same year car and then have no worries.

 

[Fett]

Yea, that is what I am thinking. I figure I can jump the harnesses and make it work, but like I said, I would rather swap as much of it as possible, that way I KNOW what is in my car.

I am going to use the charts in that link, as well as some I found on veryuseful.com. to hopefully get this all fixed. The only thing I couldn't find is the vac line set up for a 91+ Mustang. I found the vac line diagram for an 88, but that is different then the one I need. I will keep searching.