911sc runs bad timing problem

[tirwin]

Porsche fan,

FV is the frequency valve. It is controlled by the ECU under the passenger seat. A simple test is to turn the ignition to ON (but don't start). Take off the air box cover and remove the air filter. Inside the air box is the pressure plate. It's a valve on an arm. If you just barely lift up on the plate you will hear the FV buzz. Don't do it for more than a second or two. That will tell you it is at least working.

[Porsche fan]

Hi Paul,

The FV is working.

[boyt911sc]

Originally Posted by tirwin

Porsche fan,

FV is the frequency valve. It is controlled by the ECU under the passenger seat. A simple test is to turn the ignition to ON (but don't start). Take off the air box cover and remove the air filter. Inside the air box is the pressure plate. It's a valve on an arm. If you just barely lift up on the plate you will hear the FV buzz. Don't do it for more than a second or two. That will tell you it is at least working.

Tim,

Another method to test the FV if you don't have a dwell meter. There is no valve any where the metering unit except inside the FD. What makes the FP run with ignition switch @ ON position is 'breaking of the ground contact'. There is a contact point at the AFS (airflow sensor) arm for terminal #85 (FP relay) that activates or deactivates the coil for the FP relay.

Tony