anyone know how accurate the plx m300 units are i have bought a used one with a claimed 3 hours of use, installed it and i cant lean out my idle mixture, the moment it gets to about 13.1 the car dies but idles good at about 12.5 and im not sure if its a sensor fault etc. any ideas welcome? engine is a extend port 13b and sensor is mounted about 10" from the back of the turbo

 

I'd replace the sensor. If he used leaded fuel that thing could be garbage. You can get the sensor from VW for $35 or you can get them elsewhere for $80. The bosch LSU4 sensor is only $35 let me dig up the VW part number for you.

I use the plx m300 and it works very well. Make sure your settings are correct if you have a datalogit and power fc. Also, check the calibration on the wideband.

Easiest way to do this is.

Make sure car has not been running for at least 8 hours. Turn the key to on (the wideband will turn on) DO NOT START THE CAR, just wait 30 seconds.. the wideband should go through a warmup and then read "AIR" If it doesn't, it's not reading correctly.

 

Hope this helps.

 

thanks i will try this now

 

ok i have done that, display starts off 14.7 then slowly reads leaner and leaner untill it displays LEAN then a few seconds after that it displays AIR. any ideas?

 

i'd find a tuning wideband and have someone verify it on a known good setup. No way ot know yours is good unless you test it with a higher quality wideband o2.

 

thanks for the help i will try and get it verified. cheers

 

If the engine is not on then that's perfectly normal behavior. It shows 14.7:1 by default when the controller is first turned powered up...then the display leans out as the sensor heats up. Once its totally warm it knows its reading ambient air levels of O2 (hence "AIR").

If the engine is idling while its doing that your wideband controller is smoked.

 

thats the problem im having. alot of people are telling me that often streetports wont idle any leaner than 13.1 and others say they will? im not really sure who to believe or if it is faulty.

 

I have a medium street port and it likes to idle around 13.3.

Where are you trying to get it to idle at? What RPM? Mine seems to like to idle around 1100RPM and 13.3. I can do 13.9 and have it idle at 1200RPM.

But getting my car to idle at 14.3-14.7... no way. It runs like crap and hates it.

 

So it's showing "AIR" while the car is running?

If that's the case and you changed the sensor then the controller is smoked. Don't even try to tune on it. Send it in for repair or throw it in the trash because its useless as it sits.

 

No, it's not showing air while it's running Trevor. I had him test it by turning the key to the on position and allowing it to warm up. It seems to be operating fine.

 

Im running 14.5:1 on my full bridge, and the engine can also ideal at 15:1 but goes a bit flat and sounds stock so i let it run a lilte richer,