15 replies to this topic

[dw1]

Not sure if it's a problem with my gauge but it is showing full LEAN 100% of the time. Not sure if it's a coincidence but took the car out, on starting and the first 5 minutes the Afr gauge was giving good readings showing lean when off the throttle and then when applying power and driving with a level throttle it was going to 14ish, which is right. Then it went to staying on lean. I had been mucking around with the traction control and one collection of settings caused the car to have too many misfire cuts to be undrivable so put the settings back to regular. Probably just a coincidence that the two happened around the same time and not related? Is my AFR gauge knackered or is my car really running lean - which worries me big time!

[Kieran McC]

Not sure if it's a problem with my gauge but it is showing full LEAN 100% of the time. Not sure if it's a coincidence but took the car out, on starting and the first 5 minutes the Afr gauge was giving good readings showing lean when off the throttle and then when applying power and driving with a level throttle it was going to 14ish, which is right. Then it went to staying on lean. I had been mucking around with the traction control and one collection of settings caused the car to have too many misfire cuts to be undrivable so put the settings back to regular. Probably just a coincidence that the two happened around the same time and not related? Is my AFR gauge knackered or is my car really running lean - which worries me big time!

Is the censor ok apprently the pre cat ones can fail

Edited by Kieran McC, 25 October 2015 - 08:09 PM.

[dw1]

How do I tell if the sensor is working properly? The gauge looks like works through its startup sequence and then goes straight to full lean staying at a max of 20 doesn't move down from that, would that suggest it's the gauge rather than the engine as would expect to see some variation in reading' even just a small bit depending on the amount of throttle?

Edited by dw1, 25 October 2015 - 08:21 PM.

[CHILL Gone DUTCH]

Is it possible you have a hole in your exhaust ??

[DaveyC]

What sensor/gauge are you using?

[Nev]

1. Check exhaust joints (particularily the 3.25 inch V-band one).

2. Swap out the 2 lambda sensors with genuine Bosche (OEM) ones (don't be fooled by eBay copies).

 

Good luck.

[dw1]

Is it possible you have a hole in your exhaust ??

   Maybe a tiny one, but it the exhaust note sounds normal.

What sensor/gauge are you using?

  It's a PLX DM6 gauge. Has worked well in the past and I have logs of it on my vbox as a channel.  

1. Check exhaust joints (particularily the 3.25 inch V-band one). 2. Swap out the 2 lambda sensors with genuine Bosche (OEM) ones (don't be fooled by eBay copies). Good luck.

It should have Bosche OEM sensors. Does it sound more like a gauge/sensor issue than the car really is running lean? It's the latter that really worries me as it could shag my engine. Are there any other symptoms to tell if it is running lean?

Edited by dw1, 26 October 2015 - 11:17 AM.

[Exmantaa]

It will drive like sh*t, or not run at all if it was running that lean. And you probably get an EML from the OEM O2 sensor that something is not right.

 

Did you check the WB sensor's reading in free air, or do a free air calibration if possible?

[dw1]

I have a bit more diagnosis... The gauge starts showing reading when the power is turned on and NOT the engine, it's shows a highest reading and then creeps up to 20 over the next 10 seconds or so, still without the car running. Does this suggest it's the gauge and not my engine as how can it get a reading without the engine running? I have had a lot of wiring done recently and the cables run close to each other near the front sill including the traction control wiring. Perhaps this has upset it?

[Kieran McC]

Is your gauge on a switched live not a continues live,

[CHILL Gone DUTCH]

If it was perminant feed Kieren the battery would be flat very quickly

[dw1]

Switched live. If it's giving a moving reading without the engine running surely that must suggest the gauge is faulty and not my car running lean?

[CHILL Gone DUTCH]

Or you have wired it wrong What make is it ?? Artic monkey managed to wire his wrong and got the wrong data going to his ecu for Dutch software without changing the parameters

Edited by CHILL Gone DUTCH, 28 October 2015 - 06:32 PM.

[dw1]

It had been working for two years well. Car has been sitting around recently and it's plug had worked loose plugged it in, worked fine for a couple of drives not is giving worrying readings. It does coincide with my traction control being activated and doing trying out some settings that caused big misfires. I have since reverted to a normal setting. Might be coincidence or not. The bit I don't understand is the reading when the engine is not running, is that possible??

[CHILL Gone DUTCH]

the reading might be a default reading while the lambda is heating up 

 

if your 100% on your wiring and

100% the exhaust is not blowing 

 

can you turn the TC off completely and see what effect that has 

[techieboy]

 

Troubleshooting:

Upon power up, the WB analog output should read 2.30V-2.40V with the O2 sensor disconnected. With the O2 sensor connected and exposed to free air, the WB analog output should read starting from 2.3V climbing up to 5.0V within 30 seconds. If both conditions are met, your SM-AFR is properly working. If the sensor does not reach Lean/Air within 45-60 seconds, please replace your O2 sensor. Replacement sensors are available from the PLX Online Store under accessories.

 

1. The output is not showing the correct AFR readings:

 

A. With the O2 sensor harness disconnected, at initial power-up it should display between 14.6 and 14.7 (wideband analog voltage: 2.30V - 2.40V).

 

i. If it is reading below 14.5, please verify that the unit is receiving at least 12V and you have at least a 5 amp fuse. If it is still reading below 14.5 even with the correct voltage, contact rma@plxdevices.com and request a RMA number. Your unit is faulty and needs to be repaired. 

 

ii. If it is reading above 14.8, contact rma@plxdevices.com and request a RMA number. Your unit is faulty and needs to be repaired. 

 

B. Reconnect the O2 sensor with the sensor harness, with the O2 sensor exposed to free air. During the 30 second warm up phase, the voltage should increase from 2.35V to 5.0V.

 

i. Voltage does not read 5.0V even after 60 seconds:

 

a. Try another power source for your SM-AFR.

 

b. Verify that a fuse is installed rated no less than 5A.

 

c. Check connectivity of harness and O2 sensor.

 

d. Your O2 sensor needs to be replaced.

 

C. When the unit says AIR*, blow on the O2 sensor. The display should show LEAN*.

 

i. Display does not go to LEAN*:

 

a. Your O2 sensor needs to be replaced.

 

* will only show “LEAN” or “AIR” on DM-6 Gauge