1988 SR5 4x4 with 22RE engine and 5 speed manual tranny.

What information is on the diagnostic port's Tem and Ect pins?

 

Well E1 is a ground And T is the tach

T being pin 8 green/yellow

E1 being pin 3 brown.

 

Wy9 - E1 is engine ground while E2 is sensor ground. Grounding T causes stored codes to flash on the CEL. The tach signal is on Ig-.

AFAIK other pins are:
Fp - fuel pump voltage control
Cco - catalytic converter temperature
+B - battery +
Vf - digital representation of response to O2 sensor
Ox - O2 sensor actual voltage

I don't know what Ect and Tem are for.

I think the diagnostic connector is under-utilized, but a good place to start testing because it's easy to hook up to.

 

Just speculating, but Ect might be Engine Coolant temperature. It would be a voltage between zero and 5 volts related to the coolant temp. The conversion formula is complex. The code below will turn volts into temperature. (sorry about the lack of indentation - not sure how to preserve the indents when pasting into the forum.)

No guesses as to what Tem might be.

Function TempECT(ByVal ECTvolts As Single) As Single
ECTvolts = 5 - ECTvolts
Select Case ECTvolts
Case 0.0 To 0.5
TempECT = 80 + (0.5 - ECTvolts) * 100
Case 0.5 To 0.9
TempECT = 60 + (0.9 - ECTvolts) * 50
Case 0.9 To 1.5
TempECT = 40 + (1.5 - ECTvolts) * 33.33
Case 1.5 To 2.4
TempECT = 20 + (2.4 - ECTvolts) * 22.22
Case 2.4 To 3.4
TempECT = 0 + (3.4 - ECTvolts) * 20
Case 3.4 To 5
TempECT = -20 + (4.3 - ECTvolts) * 22.22
Case Else
TempECT = ECTvolts
End Select
If Units = "english" Then
TempECT = TempECT * 1.8 + 32 ' Convert to deg F
End If
End Function