Does the IAT mod work on 2.0L FS Engine?
It will not work unfortunately, and here is why:
-T "guru" W
OK, here is how the IAT mod works, as per the 1993 Ford ASE Service manual for the 2.5 L V-6 equipped 4EAT Type GF Transmission:
Do you ever notice how your car shifts really nice and hard and SOLID whenever it is cold and just started, but after it warms up it has that little hesitation in between shifts? Well, Mazda and Ford engineers put that there for all of us when they wrote the programming for our engine management systems. Well, over a year ago I found out a way to get around it in one of my ASE Service manuals.
You see, the ECU actually cuts fuel injection between the 1-2, 2-3, and 3-4 shifts for "Improved shift feel", that way the engine doesn't lurch the car into gear under WOT. Well, that is just no fun, now is it. In order to trick the ECU into NOT cutting the fuel injection, you put an intermittent cut switch in the Intake Air Temperature sensor's two wires. What this does is tell the ECU that the IAT isn't working, and it goes into a "Limp Mode", where everything is set for a worst case scenario on the engine. Line pressure on the transmission is maximized, up to 50 psi. Fuel injection is set to start conditions, and all injectors fire into each one of their corresponding cylinders simultaneously, therefore eliminating the .5 sec fuel cut.
So what does all this mean? What it means is that under WOT, when you have the intermittent switch set to cut the signal, the ECU does all the thing above, and you get one EXTREMELY SOLID SHIFT instead of that sissy hiccup in between shifts.
The imperative Home Depot Mod for all Automatic 4EAT Type GF Transmissions that came in Probes, MX-6s and 626s.
Now, remember these words are surmised from a 1993 Ford ASE Service manual for the 4EAT Type GF. And these words come from the Improved shift feel Chapter, which is under the 2.5 section. There is no mention of Injection cut and reduced torque signal for the 2.0 in 1993, it just was not in the TCM Programming. You see, the 2.0 has the ECU only for transmission and engine management, while the 2.5 has the ECU for engine management, and a separate TCM for transmission control, where the information for the torque reduction is stored. There just wasn't enough room on the ECU for the entire program code, so it was omitted on the 2.0 for 93.
NOW, there IS an IAT on the 2.0, but there is not torque cut information in the ECU, so you can cut the signal, but it'll just pull a code for a non-functioning IAT.
HOWEVER, what you (whoever says it works) may be experiencing is the more solid shift from the maximized line pressure that the IAT interruption creates. When the IAT is cut, the transmission pulls a limp mode feature out of its but and runs transmission line pressure up to around 60 psi in the line.....thinking it is breaking down. you are just tricking the transmission...
But the fact of the matter is there is no injection cut for improved shift feel by Torque reduction on the 2.0 4 cyl...the programming just isn't there
And in 94 the 2.0 switched over to a CD4E Chain Drive transmission, and the Type GF remained in the 2.5...so there wouldn't be any requiem for the injection cut on such an unreliable transmission there either.