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pikey7

Mmmmmm.... I think I have the same sort of problem as you! Frightening!

When the car has warmed up, it tends to die/low stutter when the clutch goes in! At first I thought I might have messed up the throttle position, as I replaced the cable when I upgraded, but nomatter how much I play with the TPS, idle position, or cable, it doesn't help.

I did try adjusting my little lindsey box of tricks (I suppose equivalent to your ARC2) and richening up the idle. It has helped a bit, as the problem is now less frequent, but it still tries to die sometimes.

The other one I thought of may be a vacuum leak, but again, I can't seem to find one.!!

I suppose your theory on the BOV could be right. I know I have the uprated 993 version on mine, which I've been told can hold some big pressures..... I dunno though if it's performance is down to how well it can sustain pressure??

After reading all of the MAF stuff that's been flying around, I assumed it could have been some sort of cold/warm fuel settings, but then I read that the LR MAF has a temp sensor. Unless that's faulty, then I suppose that theory's out too.

One thing I haven't done yet is to get the car to a rolling road. I know that I should, but I haven't had the time.

I'll keep an eye on this post, and see if we get some bright-spark answers!

Good luck.

Konstantin

the bigger the Turbo the biger this Problem. My k26 was ok, the k27 has this the RPM falls to 400 rpm but then it go up again. I gues If I would have a bigger Turbo it would die. If you adjust the ARC2 MIDLLE at 2 clicks richer it should be ok. If Not then the MAF ensor is to close to teh Turbo. You have to move it futher away from Turbo
Look at the pics on my site.
<a href="http://www.968turbo.de/kosMAF.html" target="_blank">http://www.968turbo.de/kosMAF.html</a>
this is the best position to haVE TEH MAF not so close to teh Turbo as huntley did.##

Konstantin

Danno

see my answer in the other thread. I had this problem too with the stock K26/6 turbo.

Danno

Actually, I think the compressor bypass valve may be partially reponsible for this stumble. WHen the bypass valve vents boost around to the intake with the throttle lifted, this boost is what goes back into the turbo to keep it spinning. However, that means that no new air is flowing into the turbo and the air-column from the K&N filter to the turbo stops. Thus the MAF sensor registers zero flow! A bigger bypass valve may even vent back more boost and cause reverse flow?

Konstantin

why don't you put the K&N IN the fender.

Konstantin

Luke

[quote]Originally posted by Konstantin:
<strong>why don't you put the K&N IN the fender.

Konstantin</strong><hr></blockquote>

like cut and glue in into the outside of that hole? Well there is still dirty air flowing from other places?!? why dont you try cutting a circular section out of a k&n and siliconing the edges. Squeeze it into the inlet of the MAF pipe? I'm positive this would restrict alot of flow though! (unless you were able to build some sort of "collector".

i smell a project.

Konstantin

why don't you use a hose then put a 90 adapter IN teh fender and then put the K&N there. The whole think requires to remove the palstik fender cover but you make this only one time. How often do you clean the K&N? I guess once a year. It is ok to open it once a year. i am not sure if a hose or pipe or whatever will pass through the fender hole. If yes everything else is easy.

Konstantin

Luke

I clean my k&n every oil change.

Danno

hey danno are you saying that upgrading to a bigger stock location blow off valve or a monster blow off valve would make the problem worse??? god you confuse me, im would not think that that makes sense, would a bigger blow off valve help it here?



Sorry to introduce yet another variable into this quagmire. Ok, I may have overestimated the actual amount of air that's recycled by the bypass valve. I guess even the largest ones won't recycle as much air as the turbo puts out, thus there will always be some flow across the MAF sensor.

But I think you're focusing too much attention on the bypass valve; it most likely has nothing to do with your stumble.

As Ian mentioned in the other thread (and I posted his photo), moving the sensor away from the turbo may help. Before you go to the extreme of cutting up your fender, at least do two things that are easy:<ol type="1">[*]adjust your idle so that the stabilizer is contributing 0% to air flow at idle (perhaps even disconnect it altogether as a test and re-do your stumbling procedure).[*]rotate the MAF so that the sensor input is on the outside curve of the air flow[/list=a]

pikey7

Guys,

I'm getting a bit lost in the jargon...

Compressor bypass valve???
Idle stabilizer???

OK, I uderstand the function of the last one (I'm not a total moron <img src="graemlins/c.gif" border="0" alt="[ouch]" /> ), but what, where and how are they??

Ta!