Z3 3.0 codes 0171, 0174,1083 and 1085

id101

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Hi all,

I've just bought z3 3.0 and on the way back to the Midlands from London I get an engine light.

It seems to run very lumpy, then smooth, then bad, then fine, I also noticed on occasion when I switch off a second or so after it stops there is a like a relase of pressured air, I accidentally just caught it at the end of the video I took (excuse the radio) that I'll try and link to in another post

I've checked the codes and got 4 p0171 p0174 p1083 and p1085. I've cleared them then gone for a drive about and after about 10 minutes or so the same codes return.

I took some pic of the live data that my reader gives that are attached.

My knowledge and understanding of these things is very poor but maybe someone might understand what is going on better.
 

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id101

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In addition the car isnt particularly responsive on acceleration and feels down on power, especially compared to the 2.8 I've just sold.
 

Stevo7682

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All codes point towards lean mixture.

Check all air intake hoses and vacuum hoses for cracks and splitting.

Also codes do point to other stuff like crank ventilation valve, coil packs, plugs etc.

But zed 3 notorious for splitting intake and vacuum pipes start there.
Stephen.
 
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id101

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Any particular ones to single out first? As I'm not great at this sort of thing I'm best looking at the low hanging fruit and then off the my indy for anything else
 

t-tony

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What description did your reader give with these codes?

Tony.
 

t-tony

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Yep, looks like unmetered air getting into the combustion. Either through air leaks in inlet boots (very common) or possibly faulty MAF.

Tony.
 

Zephyr

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Smoke test it.
it will reveal all issues.
then if sorted and still having codes unplug the MAF and see what it does.
If it works fine, replace maf.
 

Zephyr

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...Could you explain how you do a smoke test please?
You will need a smoke machine that produces smoke and connect it after the MAF input hose. Start the machine, have something on your throttle pedal to push it all the way in (if it is wire operated, if it is electric, switch key to position one and then press pedal) and wait to see smoke coming out from the problematic area.

here is a video on how this works.

 

id101

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Further info there pause and suction noise on each blip of throttle, just incase it points anywhere else.

Could a disa valve cause the codes?
 

Zephyr

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Further info there pause and suction noise on each blip of throttle, just incase it points anywhere else.

Could a disa valve cause the codes?
the disa rattles when broken as far as i remember.
what you describe is a vacuum leak.
 

colb

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STFT at 27 certainly point to a lean running condition as the others have already pointed out. Their advice to smoke test it is the best way forward, that will reveal the problem areas, split or holed vaccum hoses are the usual cause, allows unmetered air in and this is picked up by the exhaust sensors and fools the car into thinking its running lean. When it sees this it will add more fuel at the injectors to richen the mixture, it will continue adding fuel until it realises it can't correct the situation, it lights the EML up at this stage to draw attention to it and sets the codes you are seeing. It will add up to 20% more fuel until it realises its not working. Your mpg will drop dramatically when its got this problem, Do check the back lower edge of the inlet manifold for any missing rubber blanking plugs, they split and fall off, being where they are they are often missed on visual checks, smoke will find them if they are missing.
In the past I have found the plastic cam cover on a 2.2 had started degrading and had started splitting and crumbling around the No4 spark plug well, smoke test found this, fitting a good used cam cover and new gaskets solved that one. Once fixed the fuel trims returned to normal. These engines rely on a completly sealed vaccum system across the engine from Maf to exhaust, any leaks in the system will present you with running problems.
 
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