Ecmlink Idle issues - help please. - UPDATE - SORT OF SOLVED

[kumfasa]

UPDATE - Based on my assumption that the valve cover was the issue i had -10 an fittings welded to my known good valve cover.
I fitted it and the results are better but not good.

BETTER in that the car does not surge as badly and it does not stall.
NOT GOOD in that the idle is still surging and log values are out of spec.

Here is the current situation illustrated by photos.

When I attach the valve cover breather to the turbo inlet pipe (brass Fitting in the photos) the car idles rough and the STFT, ISC and Airflow/rev values all go out of spec. (See Below)





If I disconnect the valve cover to intake pipe hose and leave it disconnected the car idles great and all the log values come back into line??????????
This is essentially opening 2 unmetered sources for air. One directly after the MAF in the intake pipe and one at the valve cover breather?!?!
This seems to me to be the opposite of what you would expect. (See Below)




Just to re-iterate
With the system closed and the Valve Cover breather line connected to the inlet = rough surgy idle and bad log values
Valve cover breather open to atmosphere and inlet pipe connection open to atmosphere = good idle and log values.
I don't get it?

Any ideas?

 

[kumfasa]

Well, after too many hours trying to get it to idle accurately (With catch cans, without catch cans, 5/8 ID hoses, 1/4 ID hoses, partial crimping of various hoses in the circuit) I gave up.

I have left the breather line which was connected to the turbo inlet pipe after the MAF disconnected and plugged the nipple into the inlet pipe.

The car idles and runs like a champ, and all tune variable have stabilized and are within "Spec"

This does leave an vacuum leak or open line to the valve cover breather port (Via catch can). But this has caused no drive-ability issues and I will add an air filter to stop the engine sucking in unwanted debris when in vacuum.

The only downside to this arrangement is that I am unable to utilize the vacuum created between the air-filter and turbo inlet to suck crankcase pressure out of the valve cover when under boost.

However the reason for doing this was blue smoke under boost which I suspected was oil not draining from the turbo due to crankcase pressure. With the current setup the smoke is gone. Job Done.

While the catch cans are cheap and nasty they were not the issue.

I am still baffled as to the reason for the poor idle, but am happy with the current outcome as I can drive the car again.

 

[strokin4dr]

Such a strange issue. Have you tried posting this on the ECMlink forums? Might get a more technical response from someone with a similar experience over there.
-Ryan

 

[kumfasa]

Yes I did. Dave Mertz was very helpful but in the end unable to resolve it?
He suggested it may be some sort of resonance related to the volume of the catch-cans and lines, but it did not change with or without the catch-cans in the circuit.
I even tried different hose sizes and partial clamping of the hoses to upset the flow, but no result.