cboltster

Just yesterday I got a Fabspeed exhaust and chip insalled on my 93 C4 standard coupe. It is running incredibly rough now. When gas is applied things are mostly fine, but as soon as I pop the clutch and release gas in or go to neutral the car idle falls to 300-400 rpm, bounces back up to 1500 or so. The car also blows a big puff of smoke at this low idle which it has never done before. I'm assuming this chip is causing some issues with maybe the air sensor or something? Has anyone experienced this or have any kind of a fix?

Sire

Mine advice would be, send the chip back, go to an tuner nearby and tune the car on a dyno.

Goughary

Who's chip is it? And what was the chip designed to do?....they are all a little different.

Aside from that. You likely need to clean your isv. And then do an idle adaptation. If that doesn't resolve the issue, discuss w the chip people. But before blaming the chip, look at the car and make sure it's running properly...otherwise they won't be able to help.

cboltster

I'm awaiting info on the chip specifics, it is from Fabspeed specifically for the exhaust and intake setup.

911Jetta

Looks like a Steve Wong chip:

https://www.fabspeed.com/porsche-964...-chip-upgrade/

SR20Fastback

Was anything else done at the same time? Sounds like a vacuum leak somewhere, or as someone else pointed out the ICV/ISV

Sire

Stil in the main all are engines are equal, but there is always an litle difference between each engine, so I would advice not to buy an custom chip but tune it on a dyno.

Dick964

If you didn't already, try this :
Try an ECU reset (or "DME reset as some will call it...).
Disconnect the battery for 30 minutes, connect again, start the engine and let it idle for 3-4 minutes without touching anything (!).
Sometimes the Motronic/ECU has to "learn in" all possible variations with the new chip.
Take it for a drive and after warming up the engine run it through all gears.

Hope this helps.

Dick964