Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

Does vacuum control any transmission or cruise functions?

yz300

Member
Joined
Jul 23, 2016
Messages
160
Reaction score
12
Points
18
Location
vic
Members Ride
1998 vt wagon
Hi. 03 Berlina on gas. Gas smell gone now thanks to new plenum gasket but still getting check engine light at times when engine lugging too much on gas. As the revs come down (going up a hill etc) it feels at a point where it should already have changed down a gear but hasn't yet. Also, when on gas it gives the check engine light at times when using cruise control even when engine isn.t lugging. Might you guys know if any vacuum might be involved in the control of cruise control, when the gearbox changes down a gear without tramping the accelerator or have any other food for thought? I really want to hit this one on the head. A gearbox service was suggested to me not long ago which I definitely have in mind as it hasn.t been done since we.ve owned the car. Any advice would be great. Thanks, Gus.
 

Immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
22,472
Reaction score
19,902
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX Calais II L67
Vacuum is used for the climate control system. No idea if there is any vacuum sources used on the LPG system though?

Maybe the LPG system needs a service/tune?
 

Deuce

Super Stock
Joined
Feb 5, 2012
Messages
4,456
Reaction score
4,667
Points
113
Location
Snobs Rock (or so the locals say)
Members Ride
'94 VR SS V8
Vacuum is used for the climate control system. No idea if there is any vacuum sources used on the LPG system though?

Maybe the LPG system needs a service/tune?
Yeah, full electronic ecu. And only the fan control's (and brake booster) rely on the engine vacuum.
Although my old 202" on gas relied on engine vacuum for a load reference and feed gas accordingly. No vacuum (because the hose blew off) meant no go because no gas.
Although an '03 is probably using the factory map sensor for load control? Maybe?
 

yz300

Member
Joined
Jul 23, 2016
Messages
160
Reaction score
12
Points
18
Location
vic
Members Ride
1998 vt wagon
Yeah, full electronic ecu. And only the fan control's (and brake booster) rely on the engine vacuum.
Although my old 202" on gas relied on engine vacuum for a load reference and feed gas accordingly. No vacuum (because the hose blew off) meant no go because no gas.
Although an '03 is probably using the factory map sensor for load control? Maybe?
Ok. Thanks for your reply. Mental note made.
 
Top