Im curious about your post...Is the intentions of it about the " T " connector for the new Maf sensor or about the ACT sensor location. My car is an '87, ive determined that the wiring harness is an '89. I know I previously thought it was an '88 but I was wrong on that. The harness I have now already has a Maf wiring harness built into it. Every pin that I would of had to move around or add with an original '87 harness, are already in their respective places. The EEC Im going to use is going to be from an '89 as well.
The ACT link you posted was about the guy using a 1995 Mustang GT with a 1990 A9L EEC. His problem was that on the '95 he had, the ACT sensor was in the intake tubing before the throttle body and after the Maf sensor. It wouldnt work right with the A9L in that location. I double checked to be on the safe side and went to look at my car. The reason I did that is because I have an Aftermarket
BBK Upper and Lower intake. Wanted to make sure that when I did the intake swap that there was actually a place for the ACT and I just didnt leave it off. The ACT sensor was right were it is suppose to be on the lower intake on the driver side.
I'm the original owner of my '88, so I know it didn't come with any mods. I bought all the manuals within the first few months, the EVTM being the one I use the most. The first mod I did was change the speedometer from 85mph to 140mph, with less than 1000 miles on the car. A couple years later came the conversion kit, because the damn car would never idle right. There were no other options back then, it was Ford or nothing. The kit was in the car until last year when it was removed & sold.
The EEC from this kit was used on no other. I think some functions were disabled so it wouldn't throw any bad codes at the dealership or the test light. '87's & '88's don't have a check engine light. Home code readers didn't arrive until 20 years later. The T-connector as you called it, added the 4 wires for the MAF, & had traces inside that remapped some pins to others. Other than Cali cars, '87's are identical to '88. The '89's added the MAF for all 50 states.
SN95's ('94-'95) are transition 5.0's, many things are the same, some are different. They also started changing things on the Explorer, the MAFs have a flange, but are still 4-wires. As for the ACT, the extra wires in the MAF connector are only for that. If your ACT is in the lower intake, your original MAF connector would only have 4-wires. I've spent a lot of time in junkyards over the past couple years, looking for parts. We made a Fox MAF by machining off the flange on the CNC. The hot wire sensors are all the same. I've got a couple spare MAFs & ECU, am selling some soon since I don't need all these spares. AZ for $110 with no core is good, I was going to sell my unused one for $120 shipped because Advance gave me the box for the core exhange by mistake. I think cores are going for $40, JY ones cost about $15. $25 profit for buyer. They can turn any EEC-IV to an A9L by changing the PROM. It's soldered in, so not easy to do for the average guy. I still have the original SD EEC, DA1, same as yours. Do you know any model number can be used for the exchange, doesn't have to be A9L for A9L?
It's still a point of contention as to where the ACT should really be located. It really depends on the EEC you use. The A9L is setup for ACT in the intake manifold. I only posted the link to show that the wires from the ACT don't go to the MAF connector.
Because of these subtle differences, the aftermarket suppliers sometimes get very confused & label their inventory wrong. A 6-pin Ford plug won't insert into a 4-pin MAF & vice versa. The actual pins are a different size, 6-pin are a bit narrower than the 4-pin. The connector shell size might be the same. I never actually tried it, when there are so many of the 4-pins to be had.
That sounds right about your having an '89 harness or more likely, a previous owner modified the '87, like I did my '88 last year. A couple years after I installed the Ford kit, they figured out what was inside the EEC & how to do it with only a conversion harness. I'm sure Ford wouldn't even allow their supplier to sell the connectors to anyone else. When vehicles started showing up in junkyards, they could no longer stop it. Aftermarket MAF's & chips started showing up about the same time, around 1992.
Found an online version:
http://www.coolcats.net/modifying/massair.html
The entire 1988 EVTM is online on my website. Your '87 should be identical right down to the wire colors.
1988 EVTM