99 rx high idle, iac & tps codes...

[wildss8]

have a problem with our liberty rx after 2 only days of ownership.

ill describe what happened so far as best as i can..


it drove fine on the test drive despite its 190k on board, clutch and box were better than i expected, didnt overheat drop oil etc etc..
on the drive home after we got it it hesitated and jerked on acceleration but fixed itself when i gave it a bit, engine light was not on.
took it for a 250ish k round trip and it didnt miss a beat, used just under half a tank sitting on about 115km/h.

today it started ideling a bit rough so i popped the bonnet and noticed the lead arcing on the coil pack, after further inspection i noticed that it had come loose at the plug so clicked it back on and it was good to go again.

so i thought ok might as well do the plugs and leads as they looked a bit old and spray some throttle body cleaner down its throat too.
.

took off the resonator? and sprayed tb cleaner till it was clean.
stupid me didnt hook it back up before i started the car co clear out everything i just sprayed in there, so after it stalled a few times i put it all back together and held about 3k till it sounded good again.
changed the plugs (pretty old) only to find out that the leads i was given were the long boot ones which wouldnt fit but ill change them in a few days when they arrive.


since all that the thing is ideling at 1500 and is jerky again like it was briefly on the drive home and engine light comes and goes but ironically when the light is off it jerks around and when its on it dosent.

codes 31 & 24, iac and tps..


why would it throw a tps fault?
whats up with the high idle?
i made sure that all hoses were back where they should be (tripple checked)

oh and i added a bottle of injector cleaner before i topped up with bp 98 just before i did the plugs..


currently have the battery disconnected till tomorrow morning when i start it and let it warm up andshut it down again and see what its like.

[sooobi]

Maybe take it to a mechanic?

[black_2.5]

try cleaning the airflow sensor...

they can get gummed up from all sorts of crap. If that fails, try replacing the coil pack. if that fails, it could be a knock sensor or something only a mechanic can check.

[Robbks]

try cleaning the airflow sensor...
they can get gummed up from all sorts of crap. If that fails, try replacing the coil pack. if that fails, it could be a knock sensor or something only a mechanic can check.

really....
pity the 2.5 RX doesn't even have an AFM....

search for posts by ME on how to clean the IACV and throttle body
pretty sure i've posted it three times in teh last few weeks

do that first,
reset ECU
and see how it goes

[black_2.5]

pity the 2.5 RX doesn't even have an AFM....

well its not a carby.

so it has to moniter the air flow somehow.

either map or maf. i'm pretty sure the my99 had maf sensors

[Robbks]

http://www.carsales.com.au/all-cars/pri ... &silo=1011

no MAF on that MY99 RX 2.5
they use MAP and IAT.

again, it's IACV or throttle body related.

if the IACV can't open/ close properly to get teh desired idle, it'll chuck a code.
same as if the TPS cannot close properly (dirty TB, or over-tight throttle cable)

[black_2.5]

??? robbks

The MAP determines air flow through the engine by monitoring pressure in the manifold. so its effectively an air flow sensor,

And if there's an problem with the MAP, it will throw an error code and the car will have uneven idle and will drive rough. Sensor could need a clean, or it might be broken.

Or,

it could be a problem with the IACV or throttle. and even a few other things!

Either way, its free to clean both right

[Robbks]

if teh MAP sensor was not reading, the ECU would throw a MAP sensor code.
and the car would not run properly at all, it would jerk, buck, stutter, cough.

the car has given him the codes for what is wrong,
and i've given him the reason's why the codes are there.

there is the possibility that there are vacuum hoses off/ broken or an air leak AFTER the throttle body, the excess air drawn in will cause a high idle,
but in these models, the most common cause IS the IACV being dirty and unable to close/ open properly to lower/raise the idle sufficiently

from having 2x RX 2.5's (gen2 and gen3) in the family over the last three years
owning a 2.0 NA forester (exact same intake setup)
owning and modifying extensively a 99GT forester which has the EXACT SAME IACV as this model, and it was a constant cause of the TPS and IACV codes when it became dirty (frequently on these models)
owning and modifying my JDM GT TT Legacy including an entire ECU and engine loom re-wire to use a different JDM ECU to suit the new engine and all sensors.

I do know what i'm talking about with regards to EGI diagnosis on a Subaru, especially pre MY01 models

[black_2.5]

no worries!

wildss8 should definately do that then, if he ever checks the thread

[wildss8]

sorry guys just need to clarify that its a gen 2 rx not a gen 3.

its playing games atm because ive changed the iac and tps and the light is still on.

heres the weird part.

with the old iac and tps in it would idle high and hesitate/jerk on acceleration unless i unplugged the tps.

i changed the tps and it would still do it.

bit the bullet and bought a second hand iac for $110 and whacked that in.
also changed a hose under the iac that basically perished in my hand when i took the bugger off .

now with the new iac in and the old tps it drives fine (i adjusted the idle but turning the iac).

its still throwing the tps code but it drives fine with the old tps still plugged in which wasnt the case before.

i cant under stand the connection between the two codes, i mean if i changed the iac and its fixed the problem annd im still using the original tps why is it still giving me the tps code?
ill try the tps i bought and see what the deal is.

oh btw therespower getting to the tps wire and both tps' have been tested and getting signal out of the green wire out of the plug.

new iac was very clean too.

checked all vac hoses, everything where it should be .....

[sheppo9]

sorry guys just need to clarify that its a gen 2 rx not a gen 3.

Well it's not a 99 RX then, it's a 98.

Now, it might be your AFM...

[Robbks]

gen2 RX STILL DOES NOT HAVE AN AFM



back to the OP
your IAC was that clogged up with shit that the car could not get teh right amunt of air through it
the ECU could see that the IAC was probably in the closed position
but it was measuring a different airflow through the engine (MEASURED BY THE MAP SENSOR) to what it would expect from a closed throttle. so it throws you the TPS code aswell.

reset the ECU and the codes should clear. or they will clear after 5 re-starts (maybe 7 re-starts)

did you read any of that above?
about cleaning the throttle body, etc?
the throttle butterfly could still be sticking slightly and pissing off the TPS and ECU

Do you work at Subaru by any chance?
just changing parts because the ECU codes say that's the issue in the hope it will fix the problem.

[sheppo9]

gen2 RX STILL DOES NOT HAVE AN AFM

Really?

http://www.carsales.com.au/Tig/UI/PageP ... allcarhome
Or
http://www.carsales.com.au/Tig/UI/PageP ... allcarhome
Or
http://www.carsales.com.au/Tig/UI/PageP ... allcarhome
Or
http://www.carsales.com.au/Tig/UI/PageP ... allcarhome
Or
http://opposedforces.com/parts/legacy/e ... d_element/

[youngy69]

What he said,If its a gen 2 it has a air flow meter.
Cheers