Grrrrrrr. Lambda Sensors

[JamesV70R]

Yeh I seem to remember reading something like that somewhere, can't for the life of me remember where though, but I think it was to do with the ETM?

Will try that at lunch tomorrow then - is this starting from a "clean" ECU yeh? EG -codes cleared and battery pulled for a while first?

[RWD]

Been having issues with my MAF since the battery went flat the other week, Lambda light has been on a couple of times since, been the same code each time. It also came on after I changed the plugs, rotor, leads and dizzy cap last saturday. Its on at the moment, so I will be getting my mate at works code reader tomorrow and resetting it. Mine looks like the original one, so it will be getting a clean fot the time being, as funds will have to wait - Just got all the PCV bits ordered for this weekends tinkering!

[JamesV70R]

Misfiring, stuttering, dieing while idling or on the overrun.

Trued unplugging the MAF, no difference. Plugging it in - no difference. Stalled 3 times in a mile all while moving. Luckily 3rd was in works carpark.

Thick black smoke under any kind of load, lumpy low (300rpm) idle, hesitant when giving power but then smooth from about 1400rpm -> 5000 rpm. Lots of smoke though.

Thoughts?

[JamesV70R]

Hmm, ok .. had a play over the last hour ...

Few short runs, one running fine, next not so fine with a little stutter, 3rd rougher still and EML on. Was watching the OBD data while it was down around the 600/700 rpm mark and stuttering, and ignition timing for Cylinder 1 was going from -20 to +18 .. sometimes in 1 fell swoop! Holding the idle steady at about 1000 with the pedal steadied it out.

Sat chugging away at idle in the drive we tried a few things -

Squeezing vacuum pipes
Spraying injector seals + vacuum pipe joins with wynnes to see if idle settles down.

No difference, just smoking away.

As a last thought we opened the airbox, removed filter, and blocked part of the MAF grille by putting a couple of fingers over it - ooh .. no smoke, smoother idle ... Obviously blocking too much caused it to die, but by covering about an inch wide strip the idle smoothed right out and the smoking stopped.

Anyone have any ideas?

I'm leaning towards not enough fuel now - obviously its been reading how much air has gone through, and thinks its putting enough air in, and its infact running leaner than it thinks. (Filthy injectors or blocked fuel filter? Maybe a weak fuel pump?)

Are we onto something here?

[deathrider311271]

you did fit a genuine bosch MAF didnt you? and a genuine bosch lambda sensor?

i fitted a NGK lambda and the car didnt like it, put bosch one in all was fine.

i will ask again as u didnt bother to answer me last time

[JamesV70R]

Oh - sorry - Yes, Lambda was Genuine Bosch (I mentioned in an earlier post) and the MAF was an ebay special - (Didn't have £160 to throw on the car if it made no difference .. and it made no difference ... light was back on within the day)

The problem is neither the Lambda or the MAF IMHO. The Lambda has been changed 3 times now, the last 2 times they lasted <6 months before throwing codes, this time it lasted a few days. Unless Bosch have been making faulty sensors for the last 18 months ...

[deathrider311271]

ok this has been said before the non genuine MAFS are crap, they dont have the correct peramiters. Bosch or dont bother, u said nothing happens when u disconect the MAF, mine runs rough when disconected.

If its not reading correctly your fuel will be incorrect as well, could be over fueling which will cause excessive engine wear and possible bore wash, or under fueling will also cause engine wear.

im guessing its over fueling due to the smoke issue, it wouldnt do this if it was running lean.

if u cant afford a new Bosch MAF buy a known good second hand one.

simon

PS i would tend to agree with you on the Lambda issue, but definatly do not agree with you on the MAF issue

[JamesV70R]

The strange thing is that its only at idle ... Duff MAF would affect the whole rev range, wouldnt it?

Whats strange is that covering part of the MAF mesh actually makes the revs settle out .. Obviously I havn't tried that while actually driving, but at idle it stops the smoking, stops any misfiring ... At this rate a 2 inch piece of Gaffa Tape will fix the car ...

Will wack the old Bosch MAF back in tomorow as i've had the ebay one in for a few days to see if the same symptoms happened or not - and they did, meaning my old MAF is fine.

[deathrider311271]

Yep exactly, wrong peramiters on tick over, so by you restricting the air flow this is correcting it to some degree, the ECU can only do so much and if the information it is getting is out of the ECUs peramiters it throws up a light, reading back the code u had was fuel trim.

Do u have anyone near u who has a known good Bosch MAF? they would lend u it to try it and see if that makes a difference.

just an idea.

I priced up a new MAF couple of days ago £144 delivered from these guys: http://www.emissioncontrols.co.uk/pa...&viewpage=home

Genuin Bosch

cheers

simon

[JamesV70R]

Nabbing a MAF off another car would be nice, but, although I have seen a few V70s driving around I don't know any of them .. and certainly not well enough for them to let me steal a part off their car for a few days!

Yeh, restricting airflow and the idle smoothing out (with a surge I must add) made me think its running too lean ... but as you say the smoke rules that out. Will try and get a bit of video if it does it again tomorrow.