Engine Idle Issue when clutch not depressed in neutral

[Lear70]

So I'm still tweaking the tune on my car with Daz, going well, have noticed a few new issues as we've ramped up the tune.

Primarily, the idle sits at 800 RPM, regardless of clutch position. This seems kind of high to me, does it no matter what ECU is installed.

When I start the car then place it in neutral, clutch out, it seems to run OK. As it warms up, however, the idle worsens with the clutch out, varies +/- 200 RPM, even tries to die on me sometimes. It sounds like it's missing, but no CEL and VAG says it's fine as far as I can tell (NooB with the VAGCom).

If I push the clutch in, the idle smooths out. Same RPM, just no roughness.

After sitting running in a parking lot for 10 minutes, it tried to die again yesterday but caught, but when I went to leave, I got a low oil quantity warning for a split second, then it went away and never came back. Oil quantity was fine, changed it today anyway just to be safe.

Anyone have any thoughts on what could cause that?

As an aside, I'm getting a low whistle that pitches up and down at LOW engine loads as I give it throttle. I can't find any additional air leaks in the intake system, been looking for a while. It doesn't whistle at high RPM or turbos boosting, just light partial throttle, increases as I give it gas, decreases as I let out, typical city traffic, does it worst 1,500-2,500 RPM in 3rd - 5th gear. May be unrelated. Maybe not.

[julex]

Ask Daz to increase torque reserve at idle wihout clutch in, this is the easiest and quickest fix. The reason why you idle nicely with clutch in is because car increases torque reserve (opens throttle but retards timing) durinh clutch in so that it is harder to stall the car during clutch engaging.

You have hardware/tune problem, being it odd injectors that are hard to tune or maf being non-linear.

[Lear70]

Hi Julex, thanks for the input.

The injectors are Dekka 60# and the MAF is a SRM 85mm. With both of those being known items, I wouldn't think it would be that hard to tune around...?

It also follows over if I put a different ECU in it that has a hard tune setup from AutoSpeed. It's tuned for the wrong injectors which is why I can't use it but otherwise at idle it has the same problem, which leads me back to maybe a PCV problem? Some type of vacuum issue that's not showing up when I leak check it at the intake?

I can't imagine the car stumbling and sometimes trying to die when the car is sitting parked with the shifter in neutral and clutch out like going through a drive-thru or bank teller being a normal Stage 3 issue that has to be specifically tuned around...?

Also, I don't want a higher idle, I want the idle to get back down to ~600 RPM instead of 800-900 varying up and down. Would increasing torque reserve at idle also increase RPM?

[MikeyB3]

Can you take a video of the issue? I'm just curious to see if we're having similar problems.

[zillarob]

How many inches of vac at idle?

[julex]

When I asked about injectors I knew you're going to say Deka 60#... These injectors are simply impossible to tune for stock level of load at idle that is seen on 2.7t (small pots and little air coming in, thus very little fuel needed). They are extremely inaccurate below about 1.5ms pulse width which is what 2.7t idles below. Once you press the clutch pedal, that pulse width goes closer to 1.5ms and the idle smooths out. Check out the below spec sheet, especially last graph:

http://siemensdeka.com/specsheets/FI114961.pdf

There is nothing you can do yourself that will fix it.

Ask Daz to either adjust tune in a way I mentioned above or replace injectors with Bosch Ev14 model that is far superior in low pulse width fuel delivery precision and have Daz give you a tune that's proven for bosch ev14 squirters.

[Lear70]

Great. Something else to undo from the Mensa scholar I got this setup from.

Thanks for the input. I'll have to see what I can scare up in the Marketplace or ask Daz to tune around it.

I wonder if that's why my clutch engagement is so harsh also. Project B5 sprung clutch disc, pressure plate, and stock dual mass flywheel. Clutch engagement has a really harsh bite at the very end of pedal let off unless I really baby it, compared to stock.

In the meantime, have to find where all this damn extra air is coming from under boost and why my engine has a slight low pitch whistle at very low pedal input. Once the turbos spool the whine goes away, it's only present when I go from idle to a half inch of pedal input and doesn't do it unless the car is in motion (won't do it sitting still where I can try to trace it).

Thanks again for the help!

[julex]

Great. Something else to undo from the Mensa scholar I got this setup from.

Thanks for the input. I'll have to see what I can scare up in the Marketplace or ask Daz to tune around it.

I wonder if that's why my clutch engagement is so harsh also. Project B5 sprung clutch disc, pressure plate, and stock dual mass flywheel. Clutch engagement has a really harsh bite at the very end of pedal let off unless I really baby it, compared to stock.

In the meantime, have to find where all this damn extra air is coming from under boost and why my engine has a slight low pitch whistle at very low pedal input. Once the turbos spool the whine goes away, it's only present when I go from idle to a half inch of pedal input and doesn't do it unless the car is in motion (won't do it sitting still where I can try to trace it).

Thanks again for the help!

If you have CAI and thus stock air box is removed, what you hear is turbos simply making noise or more likely throttle itself. I can induce such noise easily on my set up and I have "CAI" type. Stock box makes a good job of removing any noises from air intake, CAI doesn't do any job at it.

PB5 clutch... that's as hard of a clutch as you can possibly buy and still DD it. It is what it is. Any feramic/ceramic clutch will behave like that. At least you have stock DMFW, I drove PB5 clutch on 12lb single mass aluminum flywheel .

[MikeyB3]

Any resolve to this?

[audacity]

my wifes car get the low whistle sound i think you are talking about. her car is literally air tight and 100% maybe we have experiencing different sounds but i chock hers up to the fuel pump. doesn't sound like its coming from the front of the car, put the back seats down and see if the sound gets louder.

[MikeyB3]

my wifes car get the low whistle sound i think you are talking about. her car is literally air tight and 100% maybe we have experiencing different sounds but i chock hers up to the fuel pump. doesn't sound like its coming from the front of the car, put the back seats down and see if the sound gets louder.

Well, I have 2 pumps. But the external one always made a whining noise.
My question for resolve was more about the idling pulse/bounce/surge. I have a thread on my issue, I'll cross-thread the information just in case there's correlation:
http://www.audizine.com/forum/showth...1#post10997446

[Lear70]

Any resolve to this?

I had Daz do the idle adjustment like Julex mentioned above. It got rid of about 95% of the rough idle issue. A little pulsing remains, but it's very livable.

I'm actually going to switch over to 60# EV14's while I have my engine out next week and re-tune again, make sure it's 100% leak-free before I put it back in, every vacuum hose clamped, re-run the PCV system, etc. We'll see if it's still there (or the whistle) when all that is said and done.