The 94' 3.8L Thunderbirds are all OBD I EEC-IV right? Just the 4.6L V8's that were OBD II, so the OBD II port in the 3.8L is just an unconnected inactive port correct?

USA? there is no OBD2 connector(until 1996)
back then it was a ONLY FORD OBD1 system (non standard outside of ford) EEC-IV System
uses ford only scan toll $$$$$$$$$
and has blinks codes using a jumper , per the service manual
on all fords made with EFI
the connector is call ASDL , assembly line data link, jack
for FORD only.
i will read the SM to you now.

now you answer is here, how to get BLINK codes (vast there are)

https://www.fordtruckzone.com/threads/how-to-retrieve-trouble-codes-on-your-eec-iv-system-without-using-a-code-scanner.659319/


there may be crude code reader still sold for
EEC-IV System

Ford Check Engine light Codes - FreeAutoMechanic

www.freeautomechanic.com/diagnostictroblecodes7.html

Full list of OBD I Diagnostic Trouble Codes for your Ford Vehicle. If your Check engine light is on you may have a serious problem. Scan your codes and follow ...

EEC-IV 2 and 3 digit trouble codes. - Ford Explorer and Ranger ...

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EEC-IV Diagnostic Trouble Codes - Diagnose problems in

Yes, I'm pretty sure an '87 model would be EEC-IV. It was an emissions control system, not a module, and Ford went through the previous generations (EEC-I to EEC-III) during the early '80's with all types of barely-working contraptions.

Just look on the VECI label (Vehicle Emissions Control Information) under the hood. It will tell if it is EEC-IV. If your wiring diagram is for a 1987 model, then you are on the right track. It may be difficult to find an illustration of the ground points. Those are usually only in the Factory Service Manual. And neither Chilton nor Haynes will reproduce that portion of the wiring diagrams. Alldata probably would have it, but that is a subscription service.

The manual is right. Your transmission is run by vacuum and pressure from the pump. What's it doing?

ecm located behind the right cowl panel.

1) The crankshaft position sensor picks up crankshaft position and relays it to the ICM.
2) The ICM uses this to determine base timing and sends this information on to the EEC-IV computer.
3) The EEC-IV computer uses this and other engine load parameters to determine timing advance and sends this information back to the ICM
4) The ICM sends spark to the plugs.
As I understand it, this code indicates that the input signal to the EEC-IV computer (steps 1 and 2) was erratic. When this input is missing, then the computer either fires the spark plugs at the wrong time or not at all. This would contribute to poor performance.
If this were me, the first thing I would do is go to the library and get a hold of a good manual and figure out how to diagnose this thing. I expect it would involve inspecting the CKP, the ICM (which you've replaced, but the TFI module is known to have problems, especially when it gets too hot), and all associated wiring.

The CM 96 indicates an intermittent fault in the fuel pump circuit. Note that the EEC-IV computer does not measure the fuel pressure at the rail; it only monitors the fuel pump circuit and can really only determine if the circuit appears intact or not. While measuring the fuel pressure is a good diagnostic step, as you noted, it can be difficult to set something up that allows you to measure the fuel pressure while driving. I would suggest that, rather than measuring the pressure, measure the current flow through the fuel pump circuit. On a normally operating system, pump current is an indicator of pressure. At higher pressures, the fuel pump draws more current to overcome the higher pressure. As the pressure drops off, the pump current goes down because the pump isn't working as hard. If the current drops to 0, that means the pump shut off. Of course, if the fuel pump is cutting out intermittently, that could contribute to a lack of power.
(On The Other 2 Questions (More Info Please)

EEC-IV: Ford's fourth-generation EEC system; its first to incorporate on-board diagnostics (OBD) & memory to store diagnostic trouble codes (DTCs). Their chips are soldered to their boards (meaning they can't be removed to change performance characteristics like some other manufacturers), but later versions include flash-programmable memory (EEPROM).

According with the Repair Manual, for 1991 Ford Truck F150 4.9L FI 6cyl, the Electronic Engine Control (EEC) or Engine Control Computer is located in seating area, driver side, behind dash, upper corner, mounted on dash support brackets.

How the Malfunction Indicator Lamp (MIL) Operates:
A. System OK
The Malfunction Indicator Lamp (MIL) is turned on as a bulb check when the ignition key is first turned on. The EEC-IV processor turns the bulb off as soon as it receives the PIP (cranking) signal.

B. System Not OK
If the Malfunction Indicator Lamp (MIL) should remain on after the vehicle has started, run Quick Test and has had service any DTC's. If Self-Test has pass DTC's, the (MIL) is always on, and the vehicle has no drive symptoms, go to "Section 2A"

If the MIL never comes on, go to "Section 2A".

If the vehicle is a no start, go to Pinpoint Test Step

NOTE:
When in Self-Test the MIL is not limited to Continuous Memory Codes and will also flash other DTC's. Also, Continuous Memory Codes are erased from Continuous Memory if the original fault has not occurred in the last 80 warm-up cycles (40 cycles on some applications).


Hope this helps.

Directly under the steering column just to the left.

Your van does not have OBD, but it does have a EEC-IV and MCU connector sit under the hood near the battery, will have a cover over the connector small black cover will read on it (diag. connector).Hope this was very helpful.

Could be a number of things, but a quick scan will pinpoint right direction & save money in the long run. I'm told autozone & PepBoys do it for free, just not sure if they have the EEC IV system reader, but they should have. Then get back with codes that come up, unless they can tell you right there for sure, then you can get part at same time.