More TPS & IACV Quirky Conditions

More TPS & IACV Quirky Conditions

Postby husseinholland » Mon Mar 23, 2020 9:41 pm

I'm using an '05 RSX (PND) ECU, JDM TSX harness, with the DBW TB (App Sensor) rewired for TPS & IACV, with the appropriate wires moved in the "A" connector for TPS power, signal and signal ground (A20 A29, A23), and IACV signal (A12). I have confirmed the wiring from the ECU to the connectors multiple times, the signals are all correct, just backwards (1 power & 3 ground) at the IACV connector.

What I meant by the title was that with the IACV re-wired according the diagrams - 1= (-) 2= (vBat) 3= (A12)

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....the system is not recognizing the throttle change and goes full lean off idle. I can see in the logging window that the TP % is not changing. I reversed the IACV 1 & 3 wires back to the way I had them previously, and got normal throttle response back, TP % sweeps when throttle depressed, engine responds.

It's just weird. I also realized today that based on the factory wiring diagrams, my TPS was also reversed 3 (A23) 2 (A29) 1 (A20) (L-R), but when I rewired it 1 (A20) 2 (A29) 3 (A23) as indicated in all the schematics,

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the throttle angle reads in reverse in K-Tuner, and I got P0122 error codes, so I put it back as it was. I see that in the diagnostic testing the K20Z1 uses the opposite wires (step 9, pg 11-125 RSX manual), so the TPS can clearly be wired either way, depending on application.

What I don't understand is how or why having the IACV wired correctly would cause the throttle angle to not be recognized.

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With it wired 3 2 1 it registers 0 closed throttle - 65% WOT (gas pedal pushed to the floor, I'm assuming that is another issue I will need to address). I could find any evidence of a setting where you can alter which way the TP signal goes. I don't understand why it would register backwards in K-Tuner when wired as per factory diagrams

Is there something I'm missing?

Bottom line is -

1) with IACV wired per diagrams, TP angle is not registered in K-Tuner & engine goes full lean off idle, cannot be driven.

2) With TPS wired as per diagrams, TP angle registers in reverse in K-Tuner layout window.

Thoughts or suggestions?
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Re: More TPS & IACV Quirky Conditions

Postby husseinholland » Fri Mar 27, 2020 1:17 am

To wrap this up, I ordered & received a new Honda-packaged IACV today.

Plugged it in, and rechecked all the diagnostic values. This time, I got vBat between A12 & ground ("A" connector unplugged, key on).

Installed it, and ran the engine. Now it acts as one would expect, idle is elevated when cold, drops as energy heats up. Throttle response is as it should be.

So, bizarre as it is, the problems with back feeding, TPS response were all caused by defective IACV.

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Just have to tidy up the wiring

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husseinholland
 
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Re: More TPS & IACV Quirky Conditions

Postby KTuner » Fri Mar 27, 2020 1:19 am

That is definitely an odd one. Glad you got it worked out!
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