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How do I tell if a lambda probe is working?

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Old 17 September 2002, 07:25 PM
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RRH
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1994 WRX Type R/A.
Running nicely, but a couple of things lead me to the conclusion that all may not be as it should;

* 20 mpg even when i drive it like my **** is on fire, and
* Unable to get a signal to the AFR despite trying from the ECU and directly from the sensor.
*occassionally when driving hard it loses power when on full boost, like it's misfiring- possibly running too lean? doesn't sound like det though.

so far i have cleaned the MAF, changed the plugs (and full service), removed the induction kit in case its getting too much air, and cleaned then changed the idle control solenoid.

I'm now clean out of ideas..

Any thoughts?
Old 17 September 2002, 08:12 PM
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Bob Rawle
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The misfire will possibly be coil packs on that age car, the fuel consumption/lack of reading is down to a knackered lambda which is in the exhaust headers on a jap spec car of that age.
Old 17 September 2002, 08:14 PM
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RRH
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thanks for that bob.
any idea where i can get the bits at a reasonable price?
cheers,
simon
Old 18 September 2002, 03:01 PM
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Big_Snapper
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If the lambda sensor fails will the car run lean or rich?
Keith.
Old 18 September 2002, 03:04 PM
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jonny gav
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a universal one works ok but make sure you get the wiring right

on your car the white wire is the signal (black earth and red is live)

on later cars(97 on) the black is the signal with the 2 white wires being live and earth

i fitted a later lambda to my 95 wrx and it works ok.

the lambda sensor is NOT used at WOT so no chance of engine damage

[Edited by jonny gav - 9/18/2002 3:07:13 PM]
Old 18 September 2002, 03:48 PM
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Dark Blue Mark
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You don't have to be at WOT to run lean though!

Does it fail lean or rich? would be interested....

MB
Old 18 September 2002, 04:14 PM
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RRH
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it appears to be running lean
Old 18 September 2002, 05:15 PM
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jonny gav
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if the lambda fails to give a signal the ECU uses a map it has stored, you find it runs very rich not lean?!?!?

my car ran lean at fast idle on the CO monitor in the garage but on the road was running very rich.
Old 18 September 2002, 07:44 PM
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Elmer Fudpucker
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shouldn't the CEL illuminate?.....it did when mine went
Old 18 September 2002, 08:26 PM
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jonny gav
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it didn't on mine!
Old 18 September 2002, 08:49 PM
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RRH
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mine didn't either
Old 18 September 2002, 09:26 PM
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Elmer Fudpucker
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you've both got me worried now
i'd only just bought the car,at the time(2 years ago now)when the cel came on...took it back to supplying main dealer who said the lamba probe was the cause and replaced it(must confess i didn't notice any performance woes)
....anyway,for the last week or so.my car has felt a bit 'wooley'....at first i put it down to the normal unleaded that i put in on the way home from 'trax'....but the performance deteriorated further to the point where it wouldn't rev past 6000.
and its throttle response was totally crap.....soooo.......
....i changed the plugs,which improved it a lot(but not to how it was)and i've just replaced two cracked coil packs
and left the battery off,while i sat down and watched the footy.....thinking 'job done'.....but,maybe not!!!

i'll let you know what happens








[Edited by Elmer Fudpucker - 9/18/2002 9:29:49 PM]
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