Hey all - newbie to Aerostar portion of this site, may take on a project on '93 with 3.0L. I will post details like codes, etc, shortly but as I expect to look at the MAF I happened upon the below link for a simple test using just a multimeter:

Part 2 -Ford MAF Sensor Test (P0102, P0103, P1100, P1101)

Has anybody done this? As I was verifying the pinout info I noticed that the wiring connector at the MAF on this '93 had different color wires than the Chilton wiring diagram that I got at the library. Then I noticed that higher up in the harness those wires were different colors; and THOSE colors matched the diagram. So I stripped away the rest of the tape and saw splices that look like they may be factory, but then again may not be. The retaining tabs on the connector were also broken off, and the P/N on this MAF doesn't seem to match any of the options showing on sites like Autozone, although it's somewhat close. It's as follows:

F37F-12B579-FA

I realize that there could be many explanations for that P/N not showing up but when I look at all the above info I wonder. Ideas? Thanks,

92

 

I would avoid anything that breaks the insulation on the wires, as moisture WILL get in and corrode the copper.

I have had pretty good luck sticking solid wires into the back side of the connectors where each wire goes in. They each go through a small rubber hole (grommet) that closes tightly around them, and if you get a short length of stiff solid copper wire (maybe 20 gauge) you can slide it into the little hole alongside the wire. You may have to fiddle with it a little to get it to contact the pins inside. Then use alligator clips to connect the wires to your multimeter.

The trick is to find the wire size that's stiff enough to push past the insulated wires in the grommet but small enough fit into the hole along side the insulated wire.

 

no splices in the MAF wiring of my '96, same MAF since factory, 185,000 miles. just clean it.

from the wiring splice info stated, I suspect that the MAF sensor or the complete MAF unit has been replaced with a non OEM unit.
verboten on even the older OBDIV systems, pre OBDV
the MAF unit and sensor are designed and calibrated for one engine powertrain body weight and performace design. same air tube, same throttle body, same plenum, same intake and intake valve, same cyl. flow rate.
changing unit to non OEM leaves the PCM trying to calculate from wrong intake air information data.

the PCM air/fuel data tables are very different across the 3.0L engine platforms. Taurus is not the same as an Aerostar of same year.

There is a complete MAF troubleshooting section in the Ford Aerostar service manual. complex and detailed. I've used it a number of times. suggest the service CD/DVD

The programmed values within the EEC are different for each vehicle/ year / engine / transmission model. Flow-Charts are not changeable, they are forever burned into the processor. These numbers within the scalars, functions, and tables can not be replaced. But they can be substituted with numbers by a chip, more on that later. The EEC only has one or two Flow Charts that are a lot larger than my simple example. The engine Flow-Chart is all combined and creates the system �Strategies,� a second flow chart can be added for vehicles with automatic transmissions. It runs these flow charts at incredible speeds, a sequential fuel injected V-8 engine needs the injectors, and spark plugs activated 4000 times a second at 6000RPM. EEC-IV operates at 15MHz, that�s the ability to do 15,000,000 tasks in one second. But there is more to do than send out a spark signal, reading a sensor takes one task away, EEC-IV has to check sensors in-between firing cylinders. So if you�re doing the math, we still have the capability to do 1000 functions in-between injector and spark plug firing. We don�t really need to go any further into this boring math, just understand that it works.

The Intel 8061 processor chip holds the factory fuel injection program and commands the entire system. Within the program are Scalars, Functions, Tables, and Flow Charts. A Scalar is “a single numerical value assigned a label.” It sounds more complex than it really is. A common easy to understand example is the engine limiter: “REVLIM = 6000.” Functions are graphs, but Ford like to call them functions. It’s usually an input vs an output. So more input causes more output and vise versa. Tables are more complex than functions and are 3 dimensional graphs, when 2 inputs influence an output. The flow charts combine the basic scalars, functions and tables to dictate within the program to calculate an output. Flow charts are more for human understanding than computer function; it helps us to look at a complete thought.

 

That's awesome info, thanks folks. I may run the simple multimeter test on this MAF just to see what it reveals, but the bigger concern is that it's not the right MAF for the application. Anybody have a way to cross-reference that P/N and see what it's actually supposed to fit? I'm gonna go hunt eBay for that manual, thanks,

92