HVAC vacuum line routing under hood.
05-29-2012, 11:52 PM
#1
HVAC vacuum line routing under hood.
I need to know where the thin plastic HVAC line behind the distibutor goes. If anybody has a pic or diagram I'd be forever in your debt. I know it feeds the vacuum controlled HVAC C68 system, I also know I didn't put it in the right place after I did my injectors. So now my HVAC system can't controll the various settings, air just flows from every orifice at any setting.
05-30-2012, 12:05 AM
#2
There is a pic somewhere in the FSM that I cannot find but its easy... I'm sure someone will post it. I've seen it here many times.
The source is 1 of the 2 small vac fittings on the rear of the plenum. This line runs around between the dist and plenum where a vac check valve is located by the bottom of the dist...right under #1 pole.
There there are 2 'exit' lines...one goes to the hardline thru the firewall that enters behind the dist on the firewall...(do NOT break it off...PITA to replace/fix) and the 2nd line runs across the firewall to the cruise and beyond. Sometimes there is a T over there where it meets some evap lines IIRC...
Most important is the source line that splits at the check valve into 2 where that goes to a/c and cruise.
The source is 1 of the 2 small vac fittings on the rear of the plenum. This line runs around between the dist and plenum where a vac check valve is located by the bottom of the dist...right under #1 pole.
There there are 2 'exit' lines...one goes to the hardline thru the firewall that enters behind the dist on the firewall...(do NOT break it off...PITA to replace/fix) and the 2nd line runs across the firewall to the cruise and beyond. Sometimes there is a T over there where it meets some evap lines IIRC...
Most important is the source line that splits at the check valve into 2 where that goes to a/c and cruise.
05-30-2012, 12:19 AM
#3
There is a pic somewhere in the FSM that I cannot find but its easy... I'm sure someone will post it. I've seen it here many times.
The source is 1 of the 2 small vac fittings on the rear of the plenum. This line runs around between the dist and plenum where a vac check valve is located by the bottom of the dist...right under #1 pole.
There there are 2 'exit' lines...one goes to the hardline thru the firewall that enters behind the dist on the firewall...(do NOT break it off...PITA to replace/fix) and the 2nd line runs across the firewall to the cruise and beyond. Sometimes there is a T over there where it meets some evap lines IIRC...
Most important is the source line that splits at the check valve into 2 where that goes to a/c and cruise.
The source is 1 of the 2 small vac fittings on the rear of the plenum. This line runs around between the dist and plenum where a vac check valve is located by the bottom of the dist...right under #1 pole.
There there are 2 'exit' lines...one goes to the hardline thru the firewall that enters behind the dist on the firewall...(do NOT break it off...PITA to replace/fix) and the 2nd line runs across the firewall to the cruise and beyond. Sometimes there is a T over there where it meets some evap lines IIRC...
Most important is the source line that splits at the check valve into 2 where that goes to a/c and cruise.
I'm missing that check-valve also and I'm almost positive this is the reason I can't control my HVAC and you're right about those lines, they snap like twigs if you man-handle them 
I'm hoping that I can get my HVAC control back when I get the lines where they should be because I'm not messin with that crazy valve. These lines weren't right when I got the car but I didn't think anything of it untill the other day when I used the A/C.
05-30-2012, 12:52 AM
#4
Race Director
The source of the vacuum for the cruise control and HVAC system is the rear vacuum fitting (to the left of the fuel pressure gauge in this pic) on the passenger side of the plenum. It goes around the front of the distributor, like so:
On the driver's side of the distributor is the vacuum check valve (vacuum source on the left), which splits off to the bottom in this picture and goes to the cruise control. The HVAC system vacuum line goes off to the right and then under the distributor in this pic:
Agent86 posted the following picture when I was repairing my vacuum lines after I had a fire. It shows the vacuum line from the vacuum check valve (behind the pink distributor power wire with the white connector), which goes across the back of the engine and into the engine wiring harness and from there it goes through the bulkhead feedthrough and into the cockpit (on the left side of the pic):
On the driver's side of the distributor is the vacuum check valve (vacuum source on the left), which splits off to the bottom in this picture and goes to the cruise control. The HVAC system vacuum line goes off to the right and then under the distributor in this pic:
Agent86 posted the following picture when I was repairing my vacuum lines after I had a fire. It shows the vacuum line from the vacuum check valve (behind the pink distributor power wire with the white connector), which goes across the back of the engine and into the engine wiring harness and from there it goes through the bulkhead feedthrough and into the cockpit (on the left side of the pic):
Last edited by Cliff Harris; 05-30-2012 at 12:55 AM.
05-30-2012, 01:01 AM
#5
OH JESUS!! YA GOT ME SCARED!! (Thank you VERY VERY MUCH for this help and these pictures by the way) Things are very different on my car, where is the regulator line going??? On my car, the regulator is going right to the plenum, in that pic the regulator is going to the front and looks like it "tee's" off something. Does that "check-valve" have a tee on it? can I get that from the dealer?
05-30-2012, 12:28 PM
#8
I just sorted things out and properly ran the lines (one of them was backwards) and now the C68 is working perfectly, ice cold air and is blowing hard on the proper settings THANKS EVERYONE, it was in the 90's yesterday and it would've gotten UGLY!!
Last edited by caddyboy84; 05-30-2012 at 12:30 PM.