1G Idle only fixes with base timing set

[91tsi617]

Ok, I did search, and couldn't find anything close.

I have a 90 TSI I picked up with some gremlins. It has an idle around 1800 rpm. No surge. The biss screws all the way in. BLT wouldn't hold pressure, but I suspect a weak bov is the cause as it puffs air at idle (speed density system).(prior owner put a vortech bov on...why?...and there is no spring pressure adjustment like on a greddy).

I was playing with DSM link on it and when I select base idle the car drops to about 1000 and holds steady....any reason anyone can think why?

 

[pauleyman]

If you ground idle/timing plug all that does it set your isc to the middle and take timing adjustments away from ecu. Idle dropped because isc moved. If biss is all the way in you either have a leak, bad isc or bad ecu.

 

[91tsi617]

Awesome, thanks!

 

[tsi617]

Could the bov puffing air out at idle cause the leak. I assume so but just want to be sure before I tear into it to deep.