I'm planning the junkyard MAF conversion. I've taken apart the wiring harness of a 97 302 F-150 and found that all peripherals requiring power have a common (red) lead. That includes all injectors. According to my Haynes manual, this lead goes into ECM pin #11.
1) Does anyone know if it goes to pin 11 in a Mustang A9L ECM? I think it should! BTW, am I right in assuming the read lead means 12V? I know where the other leads from each injector go.
2) I'm having a hard time figuring out how to splice the new injector harness into my old (1988 302) harness, as the old one is of course all wrapped up and partly behind the upper intake. Does anyone know how hard it is to just isolate all injector leads and replace them with the new harness? It would help me a lot if I would know what to cut where before I actually attempt to do it

Thanks to Chris, this is the last hurdle for my junkyard MAF conversion. Once that is solved, I'll make a website for everyone's perusal.

 

I spent some time a last weekend unwrapping half of my harness on the lower plenum.. I do not think you can pull back the wires all the way to the computer, they are way too intertwined. It would literally take you 3+ hours IF it were possible. If you know the colors you need, unravel the injector part enough to get to it and cut and solder what you need to do. Make sure to use plenty of heat shrink and wrap it back up well. That make sense?

 

I say run new wires. When i have a car that has a bad harness, and it is a P.I.T.A. to change the whole harness i'll just run new wires and splice them into the bad wires at each end.

-Jon

 

I think thats basically what Jerry is saying.
Bjoern, I recommend practicing your soldering. It is way better to soldier than just mash wires together. The soldier(sp?) is stronger than the wire itself and provides a very positive connection.

 

Thanks for the replies guys. That's what I feared. I'll probably have to get a 87-91 harness off the wreckingyard, splice and solder the injector, O2 and MAF wires into it and just swap the entire harness instead of spending the whole day trying to solder in the engine bay. That's too sad
Anyway, once I got the harness, I'll shoot some pictures and start a MAF conversion webpage...

Bjoern

 

I just made a seperate "jumper" harness. And then wrapped them in the original harness.

 

SVOMike: So you cut and soldered injector leads #1+2 from your old harness and ran the rest dirctly to the ECM? There's this blue cap on the ECM connector that has just as many holes in it as there are occupied pins. I assume you drilled holes in this blue cap for the new wires? besides the six other injectors, you only needed the four MAF wires and the three wires for the second O2 sensor, right?

 

See if this helps:



Take care,
-Chris

P.S. The colors are just for the drawing. They are not representitive of the actual harness.

Although, 37 & 57 should be Red

58 should be Tan

59 should be White

 

Perfect! That's exactly how I figured I would do it! I'll use that diagram for my webpage, if you don't mind? I still wonder why the wiring diagram in my Haynes manual says pin #11 instead of 57 and 37, but I'll have to double check that anyway.
Now where can I get the pins for the ECM connector?
Did you get the O2 and MAF connectors new or from a junkyard?
Almost there!
Thanks so much guys!

 

There are several wires that tie into the same circuit as pins 37 & 57, including pin 11, but all of them, except 37 and 57, serve another purpose, or supply voltage to another sensor/valve/solenoid. 37 and 57 are spliced together, and go straight to the injectors.

BUT, it doesn't matter. You aren't going to change those wires.

Get your other connectors from a junk yard, as well as the ECM 60 pin connector, with as many wires, as long as possible, in it. You will use these for your new wires that go into the ECM.

Get to work!

Take care,
-Chris

 

I did . I found another little problem: the air charge temperature sensor. In the extra lower intake manifold that I intend to use, there's no place for the ACT sensor (it's off a 1996). Can I place the ACT sensor somewhere in the intake tube as well (isn't that where it is in the newer trucks?) or do I have to drill and tap a hole in the manifold (wouldn't be a big problem, I think)?

 

bjoern,

On my '95 the sensor is in the airbox upper section, between the filter and the MAF. Mine uses the smaller type sensor than the manifold mounted units.

 

Chris,

I double checked and your diagram shows the Mustang (or 351) firing order (just to let people know that check out this thread).


Since you're doing a lot of Mustang modding, too: could you scan me the wiring diagram of a 89-93 5spd Mustang? I'm getting the A9L computer and would like to double check all the wiring without having to buy a whole manual! That would be too cool!

Thanks a lot in advance!

 

I've been very busy lately, and in fact today is the first time I've turned on my Mac in a week. I'll see what I can do, but it may take a while.

Take care,
-Chris

 

I'm busy too, don't worry! I can only work on the harness at a snail's pace. I'll try to make it to a library, but that might also take a while! So no stress, if you happen to think about it in a quiet moment, I'll be very happy, if not, I'll eventually find some time to go to the library. Thanks a lot!