get some

Hi there- I hope this fits with this thread:

My new to me 964 "hunts" at idle. But it has also starting pinging and missing under more than 1/3 throttle. So far I have:
-pulled the primary distributor vent to confirm the distributor belt is rotating per other posts here
-hunted for wire arcs with the motor running in the dark
-pulled the primary distributor coil wire- interesting- car will not start
-added a can of octane boost this afternoon
-check engine light is not on but it does function
-earlier today the motor stalled 3x with a/c running
-Previous owner installed an SW chip a few months ago rated for 91 RON (no affiliation). I pulled the SW chip, re-installed the factory original...issues persist, reinstalled the SW chip this afternoon
-tried the "misting the plug wires" in the dark- no visible arcs

Note- car has extremely clean smog three weeks ago and does not have LWF to my knowledge.

Inputs please and thank you.

evoderby

Stalling issues are really annoying. Since you're in the Netherlands I can suggest two options for you:

1) Visit Van Beek Autoracing in Leidschendam and have them remap the idle strategy in your Motronic.

2) Simply remove the resin seal on your ISV and turn the adjusting screw further inwards to raise your base idle mechanically. This works perfectly -however do make sure enough thread engagement is left on the adjusment screw to prevent the engine swallowing the screw!-



Rgds,

Harald

Gus

try cleaning the ISC /- it is easy to do and you can find a lot of info on the site as to how to do this -
While you have it off you can check the position of the slide valve that controls idl through the two hose fittings. Also you can see what happens when you screw the allen screw in or out. YOU will see the valve move closed or open. Note: that when activated the ISC is controlled by a coil spring/electrical impulse that lets the valve oscillate thus controlling the air flow.
But before you remove the ISC have the engine idle, then disconnect the electrical connection and see what happens to / with the engine. This will tell you if the ISC is working / or not.
NOTE: Before you start screwing the allen adjustment screw in and out - MAKE SURE YOU MARK A start position and then count turns - This will insure getting back to your start point
Like I said before - GREAT avatar

gchristofi

+1 for the idle adaptation, my 90 c2 is similar after battery disconnect.