SOB (save our brat)

[larry3.14]

     So I inherited a 85 brat with a ej 22 conversion.  After many hours and several small repairs including a idle air control cleaning I am having a problem with the tps.  I started tracing wires back to the ecu and found a problem with the tps power and signal wires.  The information I have found on the internet claims pin 58-2 to be the signal wire.  white wire at the tps sensor however it is black at the ecu and was clearly grounded in a harness which appeared to be factoryish.  The opposite was true for the ground wire, black at the tps and the b58-1 pin has a white wire.  My next step was to make a bypass harness for the tps/idle four wire set up.  I grounded pin 58.1 and ran a wire back to the tps black wire (position 4).  The red wire voltage seems good at 4.7 volts (position 3) I left it alone.  I connected a wire to pin 58-2 and ran it back to the white wire (position 2) on the tps.  Which leads me to the problem I am having now.  Set up like this it seems to run well with the exception of a high idle.  Good throttle response anyhow.  So I turned my attention to the idle switch wire, brown and on pin 56-6 (position 1) on the tps.  I reads a constant 4.7 volts.  The voltage originates from the ecu and not the tps.  Removing the plug from the computer and testing pin 56-6 I get 4.7 volts.  So my question is.  should there be voltage at the idle switch and the tps works by grounding it out when the throttle is closed?  Or am I getting some kind of feedback through the ecm because of the shotty  harness install?   Is there something else hooked to the idle circuit that might be causing this?  Is the info I have on the ecu pinout incorrect?  Just chasing my tail at this point.  Please help.   

[TOONGA]

What year car is the Motor and ECU out of?

 

There may be a difference in pin out diagrams.

 

 

TOONGA

[larry3.14]

I wish I had that information.  From what I have seen at the wrecking yard it is out of a 90-94 wagon obd 1 four wire tps

[Gloyale]

Sounds like a 90-91 harness......and yes.....wire color for the 2 TPS wires from pins 1 and 2 flip flops at the engine connector.....not sure why.......black becomes white, white becomes black......normal.  I'd put it back how it was when you found it......Probably correct unless something was shorted or obviously hacked/spiced.

 

TPS idle switch should read voltage when throttle open.......should drop low (grounded) when switch closes at idle.  Since you've got constant voltage I would say the Idle switch isn't closing.

[larry3.14]

I want to start off by saying thank you for the responses.  So if I switch the signal and ground wires back to the way they were the black wire (number two position) is grounded.  About eight inches up in the harness it branches out with what looks like a factory connection and grounds.  Then the white wire is signal and it is in the number one position.  This has me perplexed since it is transposed form every ecu pinout I have found.  Also wired this way idle circuit seems to work fine but the signal wire is messed.  Causing a good idle but no throttle response.  So I want to ask another question about the tps idle circuit.  When using my jumper harness and connecting the wires following my ecu pinout information (transposing the ground and signal from how I received it)  I get the constant voltage from the idle pin.  So my question is.  Is the tps supposed to supply voltage to this pin when the throttle opened?  Or is the voltage supplied from the ecu and the tps is supposed to ground it when the throttle is closed?  If the tps works by grounding the supplied voltage from the ecu Then maybe all four of my used tps sensors are bad....Possible but seems unlikely.  Oh I want to add the way I received the car the white and black wires don't just change colores with eachother when passing through a plug.  The black wire in the number two position was in fact grounded.

Edited July 21, 2014 by larry3.14

[Gloyale]

 

Here is the scan from the 90 FSM.......>And a good chance to explain a typo I found only recently..

 

So, As you can see.......Coming out of the ECU(pins 1-2) and through the SMJ (B27/F45 connector..pins N6 and M6) the 2 wires in question are White, and Black respectively. 

 

IGNORE the markings at connector F26/E2 (engine connector) pins 7 and 5.........they are not LightGreen/Red and Black/Blue as indicated at that connector......this is a typo......again the Harness side of the connector.....pins 7 and 5 are White and Black respectively..........

 

BUt on the enigne side of the connector........the wires swap colors.....shown in diagrahm........and actually correct not typo.