Nissan Micra fault code - lean running...

[akku]

OK, not that retro but old-ish and need some advice, A lady of my acquaintance has an old Micra (late bubble shape thing) which is lighting the engine management light on the dash and the decode for this is that its "engine lean running condition".

Local garage has changed air filter and some other part I'm not sure of and now seem to want to replace the cat which seems odd to me.

Anyone any thoughts on this one

cheers

[scaryoldcortina]

Lambda sensor would me my first guess, certainly long before changing the cat. I'd be concerned that the garage don't know how to fix it. (I'd be scoping the front lambda sensor first, and changing it if it isn't switching. Cat health check can then be done by scoping the post cat lambda (which should read lean and not switch)

Worth also looking at fuel filter and rail pressure sensor in case it's a low fuel pressure problem... does it start and run ok?

[akku]

It drives. Not sure how well...

Thanks for the suggestions I'll be back...

[akku]

OK, its a 2001 not a "late 90s) one. Its an auto if that makes a difference.

It runs "OK but a little rough". Its had one O2 sensor replaced as it was unresponsive (she can't remember which one but has the paperwork at home), Petrol filter replaced. Fault code Engine running too lean reappears constantly.

After the last repair it was fine until some motorway driving and then the code has reappeared.

[scaryoldcortina]

It's normal for codes like this to only appear after a longish run out - the ECU needs to complete a drive cycle including full warmup before it decides something is up.

New lambda? how long ago, OEM or aftermarket and which one.... (Front one does all the work, back is only for checking up on the catalyst) They don't last forever, and I've seen cheapo replacements fail surprisingly quickly.

[akku]

She has been taking it to the Nissan main dealer so I assume they fit Nissan factory parts to it.

[scaryoldcortina]

I'd assume that too. Still, if it turns out that they fitted a lambda 5 years ago it might be worth looking at again

[Brigsy]

Have they checked the fuel pressure?? if the pump or fpr is on its way out it wont be happy.

[akku]

I believe all this is in the last few months. Will check.

[markbognor]

I've just had this reply from Frank - who is a bit of a micra guru.

"It's usually the bosch type maf on the coilpack ones eh mark, or else 2nd lamda, p0171 system lean bank1"

Thread here

[akku]

Cheers

so it would be a MAF replacement to sort this?

[akku]

Apparently, the MAF was checked by Nissan and they say all is OK with it.

The lambda sensor (still not sure which but both were tested) was changed 2 weeks ago

[rustempire]

Not sure about later models but earlier K11's are famous for getting dry joints in the throttle body causing rough running.

It can be fixed with a soldering iron, some silicone sealant and an hour of free time, I've done a couple myself.

I can't look now cos I'm at work but there's a brilliant guide on the internerd somewhere, Google something like "K11 throttle body fix"

Obviously if the later ones are different (or it's a K12) I'll just shut up and politely retire

Rob

[duncancallum]

again as said if we are talking a K11 model (chassis something similar to sjnfcak11******)

1-rear o2

2-dry joint on the maf. You can use an almera maf on them and swap the resistor over to correct the units calibration