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O2 sensor or fuel??
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Old 09 Feb 2011, 02:35 AM   #1 (permalink)
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O2 sensor or fuel??

Chaps, need some advice again. The car is a 2002 WRX 215 with no mods at all. I have mentioned these before, but am still having the problems.
1 - very slight erratic idle. It idles at 750rpm on the needle and doesnt move, but there is a slight erratic rumble felt through the seat accompanied by a very slight change in engine noise. Not a contant rumble, but an ever changing rumble of varying proportions. Does not stall, hunt or move anywhere else. I have noticed that sometimes when the car is coming to a stop and the revs are lowering, I can feel the same erratic rumbling in the engine.
2 - There is a slight hesitation on harder acceleration at 2000-3000rpm. I reset the ecu and it clears the hesitation, but after a few days, the hesitation comes back. Because it goes with a reset, i know it is not turbo or hose related and must be something sensor/fuel related. I have run it through Learning View and it is ALWAYS in the same rev range and at low loads where the fuel is being pulled. See attached.

I have checked/changed - Sparks, BCU, coil packs, MAF, TPS, IACV.

No stalling, cutting out, loss of power and no CEL.

I put a tank of V-Power in and reset the ecu and will be putting a 2nd tank in later this week, but it hasnt made any difference so far. The only thing left is the O2 sensor.

Any suggestions or do I bite the bullet and try a new O2 sensor??
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Old 09 Feb 2011, 10:40 AM   #2 (permalink)
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Re: O2 sensor or fuel??

get it to a specialist mate, you could carry on chasing it all over tryign to find it and not ever cure it.
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Old 09 Feb 2011, 06:26 PM   #3 (permalink)
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Re: O2 sensor or fuel??

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Originally Posted by Tidgy View Post
get it to a specialist mate, you could carry on chasing it all over tryign to find it and not ever cure it.
Bummer!!! I was hoping to stay away from them to save cash, but think my flexible friend has a little room left!!
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Old 09 Feb 2011, 06:38 PM   #4 (permalink)
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Re: O2 sensor or fuel??

using romraider log ur 02 and maff voltages at idle and on the road and post them up, you should be able to see a faulty maff or 02 easy enough.
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Old 09 Feb 2011, 08:47 PM   #5 (permalink)
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Re: O2 sensor or fuel??

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Originally Posted by bugeye_bob View Post
using romraider log ur 02 and maff voltages at idle and on the road and post them up, you should be able to see a faulty maff or 02 easy enough.
I have a OBD2 (my old VAG-COM) lead that works with LR, but wont recognise the ECU and connect to it when I try to use Romraider. I would have thought that it should work, but need to have a play with it. I also have an ELM327 lead, but cant find any software that allows the AF or O2 to be read. Any ideas? or is it only a Tactrix cable that works with RR?? Cheers.
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Old 09 Feb 2011, 09:16 PM   #6 (permalink)
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Re: O2 sensor or fuel??

nah a vag works
ive installed loads have you followed the instructions that come with it?
ie the ecu definitions and the logging definitions? you get a option of metric etc ?
RomRaider • View topic - Latest RomRaider ECU Definitions (v 0.8.3.1b 10-07-09)
RomRaider • View topic - Latest RomRaider LOGGER Definitions (v0.3.5b 10-02-09)

most install RR and think thats it
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Old 10 Feb 2011, 02:08 AM   #7 (permalink)
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Re: O2 sensor or fuel??

Quote:
Originally Posted by bugeye_bob View Post
nah a vag works
ive installed loads have you followed the instructions that come with it?
ie the ecu definitions and the logging definitions? you get a option of metric etc ?
RomRaider • View topic - Latest RomRaider ECU Definitions (v 0.8.3.1b 10-07-09)
RomRaider • View topic - Latest RomRaider LOGGER Definitions (v0.3.5b 10-02-09)

most install RR and think thats it
I did install the defs but couldnt get it to work. I have reloaded RR, but now getting another error saying the car definitions have not loaded. Whilst searching for the answer to that, I found an article that says the 2 green connectors need to be plugged in to do the logging. Gonna do a fresh install later and then given that a whirl. Hopefully get it up and running and get the AF and O2 voltages posted.
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Old 10 Feb 2011, 09:11 AM   #8 (permalink)
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Re: O2 sensor or fuel??

never need the green plugs for logging kid
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Old 10 Feb 2011, 03:15 PM   #9 (permalink)
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Re: O2 sensor or fuel??

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Originally Posted by bugeye_bob View Post
never need the green plugs for logging kid
Cool, I am trying to sort out RR and will post back the results - hopefully!! Cheers for your advice.
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Old 12 Feb 2011, 06:34 PM   #10 (permalink)
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Re: O2 sensor or fuel??

Quote:
Originally Posted by bugeye_bob View Post
using romraider log ur 02 and maff voltages at idle and on the road and post them up, you should be able to see a faulty maff or 02 easy enough.
I have logged the data, but cant upload the results as they are on a spreadsheet.
-
However, at idle the O2 sensor voltage ranges between 0.2 to 0.74v and the AF voltages ranges from 1.22 to 2.32v.
-
At around 27mph, the O2 sensor voltage ranges from 0.1 to 0.92 and the AF 1.28 to 1.94.
-
The idle readings seem to jump around a bit, where as the others seem more stable.

Is there any way to post up the full spreadsheet? Do these readings tell you anything??

Cheers once again.
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Old 12 Feb 2011, 09:53 PM   #11 (permalink)
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Re: O2 sensor or fuel??

This may work



Doh..!!, think I might have done the wrong O2 sensor. I assume it should have been the front sensor!!
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Last edited by Goulders; 14 Feb 2011 at 07:25 AM. Reason: Cos I am a dumb ass!!
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Old 14 Feb 2011, 08:59 AM   #12 (permalink)
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Re: O2 sensor or fuel??

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Originally Posted by Goulders View Post
This may work



Doh..!!, think I might have done the wrong O2 sensor. I assume it should have been the front sensor!!
Now I am really confused (or just a numpty!!) - I have just tried to log the FRONT O2 sensor using RR logger and when I set up the logger, but before I connect to the ecu, the front (and rear) O2 sensor is listed. However, when I connect to the ecu, the front sensor option disappears!!! Does that mean the car doesnt have a front O2 sensor??
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