|
|
|
|
| Author |
|
|
Wer bremst verliert
Join Date: Jan 2005
Location: Toronto, Ontario
Posts: 4,767
|
83 911 SC Throttle Body Vacuum ports
I'm having some trouble diagnosing a no-start issue on my SC. I have a Carrera intake but have retained the SC throttle body (linkage issues.) The throttle is installed and I don't want to remove it if I don't have to.
I have Megasquirt 'running' the car. I assumed the throttle port on the front (towards front of the car) about 2/3rds of the way down the body was a good, after-butterfly vacuum source. However am getting very little vacuum from this source. Could someone please confirm if that port indeed pulls vacuum below (engine side, after) the throttle butterfly valve? thanks
__________________
2007 911 Turbo - Not a toy 1985 911 Cab - Wife's toy 1982 911 3.2 Indiash Rot Track Supercharged track toy 1978 911 3.0 Lichtbau toy "Gretchen" 1971 911 Targa S backroad toy |
||
09-30-2006, 10:54 PM
|
|
|
Wer bremst verliert
Join Date: Jan 2005
Location: Toronto, Ontario
Posts: 4,767
|
bump and a please
Saw this already but the diagram isn't clear about which port is below the throttle plate/gets intake plenum vacuum. Vacuum line mysteries w/pictures.
__________________
2007 911 Turbo - Not a toy 1985 911 Cab - Wife's toy 1982 911 3.2 Indiash Rot Track Supercharged track toy 1978 911 3.0 Lichtbau toy "Gretchen" 1971 911 Targa S backroad toy Last edited by JohnJL; 10-01-2006 at 02:18 PM.. |
||
|
10-01-2006, 01:17 PM
|
|
|
Registered
Join Date: Dec 1999
Location: Richmond, VA USA
Posts: 1,058
|
The SC and 3.2 throttle bodies have their throttle plates at the very bottom of the casting. All of the ports from various external connections are close to the throttle plate and can be seen inside the bore. In this configuration, NONE of the ports can measure air pressure more than about a quarter-inch below the throttle plate.
I would wager that you need to take your MAP source from further downstream of the throttle plate. Perhaps from the vacuum source for the power brakes? That vacuum source will be more nearly what the engine "sees" as manifold vacuum than what you can get near the throttle plate. That same "better" source also provides a vacuum signal to the EFI fuel pressure regulator which is used in the calculation of Req_Fuel. |
||
|
10-01-2006, 04:13 PM
|
|
