Quote:
Originally Posted by Speedy Squirrel
JFairman, all cars do have a vacuum limiting device. It's called the IAC and it's open all the way on hard decels.
|
Idle Air Control valve is usually driven by stepper motor and as such way too slow to be opened fully by ECU on deccel. And why should it, the whole problem doesn't really exist anymore as EFI replaced CIS. Only thing you have to do is to zero out all fuel cells under certain vacuum (for example, everything below 30kPa and above 1500 RPM) and ECU will shut down fuel on engine-brake, thus completly removing any popping on deccel which has plagued mechanical fuel injection systems before.
On some luxury cars, factory fitted a dashpot on the throttle to cushion the last few mm of throttle travel and prevent sudden RPM drop.
Which cars open idle valve on deccel?