2010 r36 cannot read engine module with VCDS

[shaunbags]

i just did a quick googletube of the PCV on this powerplant.

i suppose i could unplug the hose where it goes into the oil separator chamber and plug it to see what happens

[shaunbags]

ok, its cold in the shed haha.

pulled the PCV hose and plugged it, i though we where onto something as it went into a pretty steady idle but the idle hunting eventually came back same as before, very even and consistent with its duration.

i did note that the measured AFR was leaning out at the top of the revving, like up to 30:1 then back....

ill figure out how to do graphing, try compare o2 sensor voltage to AFR and a couple other fields.

ill update in a week when i get another chance to have a play, out of action from tomorrow.

[shaunbags]

Bit of an update on this one, swapped some O2 sensors around with some second hand units and no change.
Started looking for air leaks thoroughly and didn't find anything, used my LPG torch around all upper manifold connection areas and inlets and couldn't get it to stumble.

Did some learning on long/short term fuel trims then went and observed the car, long terms where anywhere from 25 to 40 percent and the short terms where not fluctuating much which told me it wasn't an air leak.

At the moment I'm pretty sure this is pointing to a crappy MAF, the values seemed to be hanging while it was revving up and down while I was expecting them to fall off with the revs (and airflow)... It just didn't look right to me and what I was seeing physically.

Ive got a used unit on its way now to see if that does anything positive.

[kamold]

I've managed to introduce a vacuum leak in mine
Did timing chains and guides and now there is a definite sucking sound coming from the front corner of the cam cover somewhere above the vacuum pump.
Symptoms (hunting revs at idle) make it look like the PCV valve however I've taken the covers back off and inspected the PCV valve (which I had proactively replaced about 9 months ago) and it's fine.
Cleaned and checked the cam cover gasket no issues there.
Sprayed brake cleaner around the area without any result. Can't see a split hose or plastic anywhere.
Got me a bit stumped at the moment. Can really hear the sound but can't locate it yet.

[shaunbags]

I've managed to introduce a vacuum leak in mine
Did timing chains and guides and now there is a definite sucking sound coming from the front corner of the cam cover somewhere above the vacuum pump.
Symptoms (hunting revs at idle) make it look like the PCV valve however I've taken the covers back off and inspected the PCV valve (which I had proactively replaced about 9 months ago) and it's fine.
Cleaned and checked the cam cover gasket no issues there.
Sprayed brake cleaner around the area without any result. Can't see a split hose or plastic anywhere.
Got me a bit stumped at the moment. Can really hear the sound but can't locate it yet.

Oh no! that is not ideal.
i dont suppose you can smoke test it? i wish they where a bit cheaper to purchase (for what they actually do...)

[kamold]

Yeah I don't have one but I'll have to try and get access to one. Would make it a bit easier to isolate.

[shaunbags]

ill put this on my list of things to re-invent and sell to the masses....$100 smoke machine.

[kamold]

Then you could blow smoke up....into engine bays to find leaks...

[kamold]

After making myself a bit sick and with head spins after trying the cigar smoke blowing method to find the leak, I took the intake back off and had a good look at everything. Pulled off and inspected the vacuum pump, cleaned all mating surfaces and put everything back together.
Found that the single M10 bolt at the back of the intake was cross threaded so it was causing the whole alignment to slightly skewed. Cleaned up the thread and hole and now no more leak! Thankfully was something simple/stupid.

[shaunbags]

great success! i did consider getting a vaping friend over to try blow some clouds
ill pull the intake for a detailed look if this other MAF doesnt do anything.

i am wondering if by me just deciding to clean the MAF i actually created a problem......looking at the cross sectional design of the gen 6 MAF there is potential to wash crud deep into it and there isnt a clear shot to get it out, the actual sensor unit is pretty well bonded to the housing too, i have it a bit of a tweak and it didnt budge.

there is good info in the vr6 self study guide: http://sandbox.enjoybeing.net/veedub...self_study.pdf