O2 sensor

[bembo449]

Can a dodgy O2 sensor upset the 5.0 petrol engine ?

 

[LostKiwi]

Yes. It will mess with mixtures.

 

[bembo449]

I guess theres 4 on the V8 ?

 

[bembo449]

Right ive plugged in LK and theres a permanent EGR valve fault
These are the values im seeing , anything a miss you think ?

 

[LostKiwi]

Car not up to temperature (68°) so rest of the readings are pretty meaningless. Last one where temp is 79° is better.
That said lambda values look very high suggesting very lean (16:1 AFR).


Looking at that you have a massive air leak or injectors aren't delivering enough fuel. How's the MAF? If it's showing low airflow it will run lean.
O2 sensors look like they're doing their thing and yes there are 4. Two before each cat and two after.

 

[bembo449]

Ok LK , I thought O2 Looked ok too , id been out in it but it was sat fir 2 hours before i plugged in , what values will a good MAF show? Does the EGR fault code 0400 not mean anything??

 

[LostKiwi]

No idea on 0400 code - would need to look it up.
Check the MAF values change when throttle opened.

On some cars you can disconnect the MAF and force the car into map and not use fuel trims.

 

[bembo449]

Icarsoft said EGR valve along with that code , i wasnt sure this engine had an EGR ?
Will do

 

[LostKiwi]

Most cars these days have EGRs to reduce NOx. Check all the connections to it - especially vacuum connections. If nothing found remove and check it's not gunked up. EGR problems on petrol engines are pretty rare.

 

[bembo449]

Ok , i cant find MAF on icarsoft

 

[LostKiwi]

May not have one. Could have MAP sensor instead like my Smart does. Should have some way of measuring air flow.

 

[bembo449]

Agreed , not seein EGR either

 

[bembo449]

Its got an aftermarket MAFon it thow ,shud be bosch should it not ?

 

[bembo449]

Found the egr in the end , got half way through removing it for inspection before a fonecall frm work halted play

 

[bembo449]

Found this on the bottom of the EGR valve this morning

 

[LostKiwi]

That doesn't look factory standard......

 

[bembo449]

Pretty it wasnt fitted with a sodding great hole in it , 13 mile road test at 60mph resulted in a 7.9 mpg gain and was still climbing