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Fjz-105 high idle!

Nikppp

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Joined
Nov 4, 2019
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australia
Hey guys been having this high idle problem!!

This happened when i gave the top of the engine a small degrease nothing major and cleaned the throttle body..

Rpm is at 1200-1300 hot or cold.

My scan tool shows error code P0505 - idle control system malfunction.

I went and replaced the idle control valve but that has not fixed the issue.

Checked every possible connection/hoses. Everything seems to be in place and no leaks.

I’m stumped.. any help appreciated guys.
 
Have you tried to disconnect the idle control valve to see whether the fault lies "before or after"?
 
Hi Joakim, yes i have started it without the iac valve connected via the connector but the valve itself was still in. Made no difference, and its a brand new genuine Toyota part. Unless theres a particular way the IAC must be installed?

I scanned it again just now as the rpms were getting up to 2000 in Park. Getting worse. Really concerned here.

a new code also showed up: P0120 throttle/pedal position/sensor switch A. Now this didn’t show up earlier in the week. So now could be TPS faulty?
 
When you cleaned the throttle body, did you take the TPS off? It is not meant to be removed, there is a setup procedure for a new one but I have not had any success with it.

Are you absolutely sure it isn't an intake airleak? It does sound like the symptoms for one.
 
Hi Richard, I didn’t take the TPS off the throttle body.

All I did was take the intake hose off and sprayed carby cleaner to clean the throttle body. Put it all back. That seriously couldn’t have destroyed these sensors right?

The intake hose is a bit hard and old though..
 
Do you have a service manual for the 1FZ? I only have one for an 80, but hopefully these pages may help. There is no special procedure for fitting a new IAC, the ecu just moves it by trial and error to find the right speed. If it cannot find the right speed it will put a fault in the ecu.

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Do you have a service manual for the 1FZ? I only have one for an 80, but hopefully these pages may help. There is no special procedure for fitting a new IAC, the ecu just moves it by trial and error to find the right speed. If it cannot find the right speed it will put a fault in the ecu.

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Thanks
Do you have a service manual for the 1FZ? I only have one for an 80, but hopefully these pages may help. There is no special procedure for fitting a new IAC, the ecu just moves it by trial and error to find the right speed. If it cannot find the right speed it will put a fault in the ecu.

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I will test the IAC connection with the an ohm meter. I really do think at this stage its electrical/sensor.

Would cleaning the TB with carb cleaner maybe perhaps sent something down into the TPS and clogged it? I don’t know how that TPS works but just a thought.

I already checked the butterfly, it did have gaps in the bore but I've sealed it before putting it all back together..

Everything else checks out. Ive reset the ECU, checked all fuses in the engine bay.
 
Hi Nik,

When you pulled the air intake did you by any chance disconnect or screw up the temperature sensor that is located on the rear underside of the air intake hose (on 105) ? I have had some fun in the past with it. You can check it with a multimeter or just change out the sensor with a resistor, 0.3 kOhms to 4 kOhms.

Rock
 
Hi Nick

i got the same problem as you after i cleaned the throttle area and after that its idlening fast around 1300 to 1500rpm i changed the throttle sensor its still the same did you fixed your problem if you can help the next thing I’m thinking us the idle control sensor?
Thanks Deniz
 
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