PLX wideband incorrect readings
 

I think my plx m300 is not operating correctly.

When I first bought the unit from a HT sponsor, if I would shut my car off, the gauge would go from 14.7 ish up to 20 ish then read "lean" then read "air"

Lately, the gauge when the car is shut off or under decel, it won't read higher then 18.59. Even with the car completeley shut off for 3 minutes after running it won't read leaner then 18.59

is there a way to calibrate this thing? I thought it was self calibrating but unfortuneately I can't find my instructions at the moment so I thought I would ask.

Oh yea wanted to add that the gauge and sensor are about 1.5 years old or so if that and maybe 8k miles or so. Its being used on a turbo car with nitrous from time to time and 100 octane unleaded from time to time.

thanks

Re: PLX wideband incorrect readings (suckerpunch)
 

Do you run race gas a lot? If so I'm sure the sensor took a shit.

Just go get a sensor for a VW 1.8T, should be like $80

Re: PLX wideband incorrect readings (GetawayInMoscow)
 

Maybe and I mean maybe once a month but that was at the beginning. if I do know its not even a full tank like maybe 3-5 gallons on average. Even so its unleaded. I can't see 100 unleaded messing up the sensor.

So you agree it sounds like a bad sensor?

Re: PLX wideband incorrect readings (suckerpunch)
 

Yes I have seen that happen with PLX units when a sensor goes bad.

Re: PLX wideband incorrect readings (GetawayInMoscow)
 

ok cool. REason I am asking is because the gauge will read low 12's under boost and then it rises up to high 12's and 13's yet the car still runs perfect, no breaking up or detonation and plugs look fine.

Now I might still be having fuel delivery problems but I want to make sure my gauge is reading correctly before I start replacing a fuel pump or injectors or what not.

Re: PLX wideband incorrect readings (suckerpunch)
 

http://www.amazon.com/gp/product/B000BZI4ZW

thats where I got mine.

My PLX started doing the same thing. Under boost it would not go lower than 12.6 and no leaner than 18. after a week it was mid 13's under boost and it would not go any higher than 16.

Re: PLX wideband incorrect readings (champLSinteg)
 

awesome thanks for posting that link. Much cheaper then any other place I have seen it.

From what I am reading it appears mine has the same problems as some others here. I am hoping it was the sensor the whole time and not a fuel system problem.

Re: PLX wideband incorrect readings (suckerpunch)
 

It's says 3 used and new starting at $50 - don't buy a used sensor - and my sensor after one year wouldn't go richer than 12's either, new sensor and it works perfect

Re: PLX wideband incorrect readings (base-op.1320)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by base-op.1320 &raquo;</TD></TR><TR><TD CLASS="quote">It's says 3 used and new starting at $50 - don't buy a used sensor - and my sensor after one year wouldn't go richer than 12's either, new sensor and it works perfect</TD></TR></TABLE>

Amazon.com does not sell used sensors! $50.98 is the lowest and Amazon is selling them.

Re: PLX wideband incorrect readings (champLSinteg)
 

i changed three times already in the past 2 years https://honda-tech.com/forums/images...es/emsmile.gif and we had the same readings bro. its a bad sensor. https://honda-tech.com/forums/images...es/emsmile.gif i got mine from plx, it was 79 i think.

How close are you guys running the sensor to the turbo? In the instructions, it says you should mount it at least 24" away from the head/turbo as temps of 1500F can kill it.

have you checked your wiring such as your grounds & 12 volt power - ive had some similiar problems and cleaned up the wiring and it worked fine, assuming your sensor is good

Re: (agturbo)
 

How to check a wideband sensors accuracy....
-Pull Wideband sensor out
-Blow into the sensor...it should register maximum (Lean)
-Get a lighter...light lighter up and blow flame out
-Point the lighter at the sensor and let the sensor smell the butane...it should register full minimum (rich).

If you do this procedure and it reads anywhere in between minimum and maximum, the sensor is bad or going bad.

Re: (PHDZINE)
 

Nice.

Yeah mine started doing the same switched the O2 and its fine now

Re: (JDMCRX)
 

I am unsure of the eact distance as there are a few turns in my downpipe, but the wideband is mounted a fair distance away from the turbo. I do remember reading not to mount it too close as it could burn it up so I was as carefull as I could. Its probably close to 2 feet though.


I will also check my grounds for the unit too. New unit is ordered should be here by wed or thur so we shall see what happens.

thanks for the help guys. Glad to see I am not the only one this has happened to.

Re: (suckerpunch)
 

Sensors go bad periodically, nothing you can really do about it. If your car seems to be killing sensors quickly I'd look into something else though.

Re: (glagola1)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by glagola1 &raquo;</TD></TR><TR><TD CLASS="quote">How close are you guys running the sensor to the turbo? In the instructions, it says you should mount it at least 24" away from the head/turbo as temps of 1500F can kill it.</TD></TR></TABLE>

If my exhaust was 24" long I would https://honda-tech.com/forums/images...s/emsmilep.gif

Re: (base-op.1320)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by base-op.1320 &raquo;</TD></TR><TR><TD CLASS="quote">If my exhaust was 24" long I would https://honda-tech.com/forums/images...s/emsmilep.gif </TD></TR></TABLE>

LOL, ownt!! Actually not really. I think you may be a bit mixed up......

24" = 24 inches

24' = 24 feet

https://honda-tech.com/forums/images/smilies/emwink.gif


Well, unless you mean your exhaust is &lt; 2ft........ https://honda-tech.com/forums/images...s/emsmilep.gif

Re: (KeyserSoze)
 

Seriously though, I really wonder how accurate that 24" rule is as there are a LOT of turbo people who have the wideband bung much closer than that and have not had problems.

I'll have to try the lighter trick mentioned earlier just to see..........