Which sensor for Lambda reading in PFC via commander?
 

I think my Lambda is knackered. Spoke to Andy F and he has said check the sensor reading but I dont know which one it is. There is the top left one in the sensor menu that shows 2.00 (I think its AR) and then (O2) further down that shows 0.00

Any ideas?

Cheers,

Wayne.

O2..

Simon

Cheers Simon!!

So no reading at all either means faulty sensor or faulty wiring?

O2 - it can read zero sometimes but it should move around between 0 and 1 volts roughly. If it's stuck on zero, it's either knackered or disconnected.

as said it should move around but engine needs to be warm as the sensor takes a little while to warm up.. do check it is plugged in..

Going to take the IC off tomorrow and have a look to see if the wiring is ok. I can see the plug and it looks to be connected although I can get my hand in to check it.

The last time I had it disconnected was when I fitted the new clutch in October last year. I had the down pipe off and it was laid on the floor. I'm thinking possible damage may have occured.

Ive also been into the Functions part to see if the FB control for O2 is on and it is. Am I right in thinking this switches between open and closed loop, or in ejit speak Lambda or not?

Yes it does..

if the running problem you are seeing is lambda related then switching it off should sort the running problem.

Simon

Replaced the Lambda today with a universal 3 wire and it looks to have cured the problem. It idles better and is generally alot smoother.

At idle it reads 0.86-0.88v and cycles from around 0.2-0.6v when criusing.

At WOT its a different story. I only get 0.78v which seems very low to me. I was expecting 0.8 - 0.9v.

Does the PFC read this correctly or do I need a separate guage to monitor things?

Also, whats the cheapest digital AFR meter?

Its been reading 0.82 today at WOT. Does the sensor need time or use to become stable? Also, should all lambda's read upto 1v?

At WOT it will be stable as the ECU is running a stable AFR.
At cruise is will oscillate as the ECU adjusts the fuel to try and achieve stoich (14.7 AFR)

0.82 could be quite lean, what rpm and boost were you pulling ?
But I wouldn't rely on the narrow band output of the Lambda to give you a reliable AFR reading.

Scott,

I'm not too worried as it was mapped by Andy F to 1.25bar with all the same mods as it has now.

So I'm getting 0.82v at 1.25 in 4th gear at WOT.

Also, after fitting the new lambda sensor there is no knocklink activity again. I was getting the first 2 greens but now nothing.

What I'm worried about is whether or not the sensor is reading right. Am I getting the right AFR but the lambda is reading wrong?

All sounds OK to me...although I would expect it to osciallate slowley at idle.
Maybe AndyF set the idle cell to be out side of closed loop.
This can be done by setting the cell above the ECU o2 feedback set point.

checked mine for you this morning, and at idle mine osciallates between 0.32V and 0.66V with o2 feedback switched on.

im getting 895mv on mine (andrewc monitor) @ wot, which should be 8.9 on the apexi???

but did you know that the sensor heats up over time and starts to read lean IIRC

i think bob rawle told me to cruise for a while at low rpms to bring the temps down, and then go for 1 4th gear run to get a better reading?

this could also be an indication of your fuel pump starting to die

mine was dropping down over time, and i stuck a sti8 jobbie in from ebay for £20 which sorted it all out :)

On the autometer AFR gauge anything above 0.75V is classed as rich. but if you look at a narrow band AFR/Stoich graph the voltages are a bit vague.

i have no experience of any autometer gauges, the one i use is andrew c`s scoobymonitor, which i believe, is basically a secs monitor in a funky blue case :)

Cheers for the info guys. I will monitor a little more.

On my old ECU and Scoobymonitor I got around 0.85-0.875v with this setup.

The fuel pump is a Walbro 255lt that I fitted before the mapping last year so I would imagine it still ok.

should be ok if the pump is new :)