Dongle valves and cold start.
 

First off hello everyone. I am brand new on here and need some advice please. I recently swapped my Rover diesel for a 52 plate WRX. This has been owned by the same lady for 6 years and is ok except her son and husband told me they removed the dongle valves between the intake and the throttle bodies some years ago. The son builds racing engines for bikes so I assume he's pretty knowledgeable. Apparently there is a butterfly for each cylinder with a motor and a sensor for each. I am told it is an aid to cold starting but was never Subaru's best idea and most owners remove them. I am in the dark here and assume the 4 codes on the reader corresond to one removed per cylinder. Car seems very rapid but may have a minor flat spot and I wonder if when the codes are removed this will vanish. All advice most gratefully received and please bear in mind I am an old relic, with far too many miles up me for one of these silly quick machines. The old :luxhello:girl has done 59k with reasonable history. HELP PLEASE.
Thanks,
Pete.

Hi Pete,

The parts you are referring to are the tgv's or tumbler valves, it is true pots of people remove them and appear to see no ill have you got a check engine light on permanently as they should throw a fault all the time if removed totally.

If you do not have a CEL it could have been cured one of two ways, either by leaving the motors and sensors in place and simply removing the flaps, or by altering the engine management software (mapping). It'll be worth getting the car looked at by a reputable mapper - you may even gain some extra horses or economy!

There are actually only a two motors/sensors one of each for each side!