Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   Porsche 911 Technical Forum (http://forums.pelicanparts.com/porsche-911-technical-forum/)
-   -   3.2 Surging Idle (http://forums.pelicanparts.com/porsche-911-technical-forum/1106415-3-2-surging-idle.html)

sidebp 12-06-2021 02:11 AM

Quote:

Originally Posted by proporsche (Post 11537849)
besides all the control checkings ..can you see if you still have this plug in your AFM?It goes on from the bottom of the AFM .If it is still there the fuel mix was not adjusted for a long time if ever..
http://forums.pelicanparts.com/uploa...1638717703.jpg
http://forums.pelicanparts.com/uploa...1638717827.jpg

It's not there - thanks.

sidebp 12-06-2021 02:16 AM

Quote:

Originally Posted by ischmitz (Post 11537844)
Is there a chance that someone messed with the throttle stop position and/or idle switch position? The mechanical stop defines where the throttle valve rests when the accelerator isn’t pressed. In a normal setup the throttle return spring pulls the valve against this mechanic stop and then shortly thereafter the mechanism actuates the idle micro switch.

If someone changed the micro switch position to where it holds the throttle valve open too much this could cause your issue where there is simply too much air coming through the throttle body.

Check the following: With the engine off gently start applying throttle by pushing the throttle lever where the cable connects to the throttle body. You should first hear the micro switch disengaging and very shortly thereafter the throttle valve starts opening. When releasing you should feel the throttle valve settling against the mechanical stop and then very shortly thereafter the micro switch gets actuated.

The micro-switch activates after about 1mm movement, the revs then rise. When releasing the throttle slowly it hits the stop and then the micro-switch clicks.

mysocal911 12-06-2021 03:49 AM

Quote:

Originally Posted by sidebp (Post 11538540)
I wound the screw right in and the idle dropped from around 1,200rpm to 950rpm - it was stable for about 5mins and then minor surging started (not as severe).

So surging only occurs when the ICV is connected now, right? Can you now achieve a steady 800 RPM idle by adjusting the ICV without the connector?
If so, it's time to have the DME ECU tested!

sidebp 12-06-2021 09:29 AM

Quote:

Originally Posted by mysocal911 (Post 11538575)
So surging only occurs when the ICV is connected now, right? Can you now achieve a steady 800 RPM idle by adjusting the ICV without the connector?
If so, it's time to have the DME ECU tested!

Connected it also holds a steady low idle with screw fully wound in, after about 5mins it starts to fluctuate but less aggressively. I'm assuming the delay is temperature related.

mysocal911 12-06-2021 09:38 AM

Quote:

Originally Posted by sidebp (Post 11538910)
Connected it also holds a steady low idle with screw fully wound in, after about 5mins it starts to fluctuate but less aggressively. I'm assuming the delay is temperature related.

So at last your problem is fixed, i.e. all parts normally connected, right? Glad you fixed it!

sidebp 12-06-2021 10:08 AM

Quote:

Originally Posted by mysocal911 (Post 11538926)
So at last your problem is fixed, i.e. all parts normally connected, right? Glad you fixed it!

Definetely better but feels like a workaround - presuming screw shouldn't be wound in all the way and idle still surges as it warms.

Still going to see about getting co2 checked.

Thanks for all the inputs, I've learned a ton.

sidebp 01-10-2022 04:59 AM

Hi,

Happy New Year.

Bit of a thread resurrection but I have a quick question as finally the week has come where I can take my car to a local specialist.

Is it safe to drive the car with the ICV disconnected when I take it to the garage? Reason for asking is that I have unplugged the valve, manually set the vane position to part closed and I can get a buttery smooth idle with no pulling - this feels a lot safer than having to ride the brakes and deal with the on/off jolting I experience when the valve is plugged in.

I plan to leave early morning to avoid traffic but being a touch paranoid I don't want to do any other engine damage from running it too rich/lean or risk it cutting out mid drive (I've deliberately set the idle slightly faster at around 1k RPM).

sidebp 01-13-2022 10:42 AM

I got the car to the garage with no issues.

Unfortunately, the garage (Impact Bumper specialist) believe the ECU is faulty. Big bills pending

ischmitz 01-13-2022 11:37 AM

Where are you located, U.K? Here in the U.S. it'd be pretty straight forward to get the ECU tested and if required repaired.

sidebp 01-13-2022 12:17 PM

Hi,

Yes in the UK - seem to be a few repair shops but not sure on who is reputable.

I've been doing some research about alternatives to the Motronic system as there are few available, it appears CANEMS have discontinued their direct replacement. Are there any other alternative ECU should I not be able to get it repaired?

ischmitz 01-13-2022 12:25 PM

sibebp,

Any Motronic box can be repaired. I've had boxes on the bench that were submerged in water for extended periods of time or had internal "fires" and even these were brought back to life. In terms of economics I don't see any alternative that would come even close to getting the DME repaired. Even a homebuilt Megasquirt would set you back more than buying a good used DME outright. And that is before labor...

sidebp 01-13-2022 12:31 PM

That's positive - I wasn't sure if Motronic repair was a dying art. Will do some research on some of the UK forums.

wazzz 01-14-2022 02:32 AM

Pretty sure you'll find a good pro in UK. Otherwise, we have decent people here in France too, but you'd have to ship your box across the Channel and with Brexit and all, that has become less than easy.


All times are GMT -8. The time now is 06:49 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.