HVAC VACUUM
06-15-2005, 01:43 AM
#1
Rennlist Member
Thread Starter
HVAC VACUUM
I tested my vacuum black line to the centre console and it holds 15 in hg vacuum at idle. If I pull a vacuum by hand it holds vacuum and the heater valve closes. At idle all the different colored lines have the same vacuum 2 in hg. Seems low at outlet when inlet to actuators is 15 in hg. If I slide the lever in the HVAC control the vacuum seems to work on all the settings but 2 in hg seem low?
What should I be getting? Do the actuators go bad?
Carl
What should I be getting? Do the actuators go bad?
Carl
06-15-2005, 01:50 AM
#2
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Carl,
Check out Wally's world on the 928 specialists web site.
Great write up from the mystro himself.
https://www.928gt.com/default1.htm
Check out Wally's world on the 928 specialists web site.
Great write up from the mystro himself.
https://www.928gt.com/default1.htm
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
06-15-2005, 08:50 AM
#3
Rennlist Member
Carl.........I took my car for a run with the vacuum guage connected to the black vacuum input line to the HVAC system and saw 20 in hg. The system then held vacuum for approx 20 mins after shutting off the engine. The accuators are on/off switches and when in the open position should allow full vacuum to the respective flaps/ valve. Have you tried removing the accuators and with a 12 volt source test if they're all working as they should? Perhaps there's a leak right at the actuator hose linkage?
06-15-2005, 10:49 AM
#4
Rennlist Member
Thread Starter
Malcolm,
The actuators hold the vacuum and there is electrical power to the actuators. My concern is the inlet to the actuators is 12-15 in hg but the output where the colored tube connect only see 2 in hg. I guess is the actuators are inexpensive I may just buy new ones?
Thanks
Carl
The actuators hold the vacuum and there is electrical power to the actuators. My concern is the inlet to the actuators is 12-15 in hg but the output where the colored tube connect only see 2 in hg. I guess is the actuators are inexpensive I may just buy new ones?
Thanks
Carl
06-16-2005, 06:30 PM
#5
Race Director
Carl
With the car off, do all of the colored hoses (different actuators) all hold only 2hg? Is there some actuators that hold much more vaccuum than others? If so, replace or rebuild the acutators that leak the most or hold the least vaccuum....I'm in the same boat....except for mine leaks like a sive straight from the black source at the 4 way "T"... SO I need to track down exactly which acutator is leaking really bad.... Since there is Zero vaccuum inside the dash...the heater valve has no vaccuum and was always open....a zip tie fixed that (temporary).... I'll know more after Sharks at the Lake
Brian
With the car off, do all of the colored hoses (different actuators) all hold only 2hg? Is there some actuators that hold much more vaccuum than others? If so, replace or rebuild the acutators that leak the most or hold the least vaccuum....I'm in the same boat....except for mine leaks like a sive straight from the black source at the 4 way "T"... SO I need to track down exactly which acutator is leaking really bad.... Since there is Zero vaccuum inside the dash...the heater valve has no vaccuum and was always open....a zip tie fixed that (temporary).... I'll know more after Sharks at the Lake
Brian