Found a random taped off vacuum line, help please?

**JayHerlth** · 06-09-2014

The diagrams I view (that actually have the middle line) show that this line goes to an accessory. My boost guage does not display anything, although my MAP sensor is missing the T-Connector. Which I am waiting for to show up in the mail. I'm unsure what it's for, and where it's supposed to go. I see in the photo I grabbed from the internet it follows the top of the firewall but it's too late for me to go out and check it. Though could anyone take a look and if you recognize the purpose, fill me in? I'm not too comfortable with a randomly taped off vacuum line in my engine bay...

Part #3 is what I'm referring to..

Then here is a photo of the actual line..

**Fivefingerdeathpunch** · 06-10-2014

It goes to the hvac controls inside the car.

Should just follow behind the coolant res tank and into the cabin of the car.

**JayHerlth** · 06-10-2014

Originally Posted by Fivefingerdeathpunch

It goes to the hvac controls inside the car.

Should just follow behind the coolant res tank and into the cabin of the car.

My issue is that from what I remember seeing, there is no line leading into the cabin. It's just a line taped off, cut about half way...
Is it really needed? What purpose does it serve?

**Slick2500** · 06-10-2014

It goes into the main harness wiring that goes into the car, that is why you do not see it. It does something with the hvac system, iirc it will cut off the system/lower power to it under WOT. Also the diagram you listed is for a 97 L67 hence the reason you don't have a vacuum tree.

**BillBoost37** · 06-10-2014

We are totally in the dark w/o knowing what year you drive.

Reason being is some years didn't use engine vacuum to actuate climate control soleniods. I believe all 97-03 did and the line runs from that port to the firewall, past the pass strut tower, down pass the relay center and then it goes behind the battery, across the front bumper and over to a vacuum ball located under the drivers front fender.

**JayHerlth** · 06-10-2014

Sorry BillBoost, had a brain fart there. It's a 99 GTP.

**BillBoost37** · 06-10-2014

Then look at your passenger strut tower, right by the hood hinge. Do you see a plastic vacuum line that probably nose dives behind the motor? That'll be your line.

**JayHerlth** · 06-10-2014

It once upon was tucked back there, until I noticed it wasn't on the bracket and tugged on the loose line. Only to find tape on the end.

That would also explain my wot issue. Was getting a p0101 and p0102 error. Thought my maf was bad and causing it. Cleaned it, and still nothing. At around 4k rpm it just doesn't want to go past it.

**JayHerlth** · 06-10-2014

I found the line, placed it where it belongs but no difference in performance. I am missing my connector underneath the nose of the supercharger though. I'll make conclusions after I put that part in. Would anyone know if a MAP sensor without the line connected to it code a P0101/P0102 error?

**idrivejunk** · 06-10-2014

The tee that goes under the blower snout is very important and yes it will set a code or codes if it leaks there.

**JayHerlth** · 06-10-2014

Originally Posted by idrivejunk

The tee that goes under the blower snout is very important and yes it will set a code or codes if it leaks there.

Well, for some reason the entire tee is missing. Getting P0101/P0102 errors. Had to order it from a GM dealer. Unfortunately I have to wait a week or so to see if it changes much.

**idrivejunk** · 06-10-2014

Go up to the local parts store and get a tee assortment and some hose so you can make one. I asked at a dealer and that tee only came with a $50 line. You can handle it tonight for under ten bucks.

**idrivejunk** · 06-10-2014

Heres what I did-

**JayHerlth** · 06-10-2014

Ordered the tee online and will be coming in a week or so. I guess I don't really want to wait that long. Will run up to the store on Thursday to see what I can do. Very creative, just wasn't sure if the middle line would fit to the manifold nipple. I guess it's just that elastic?

**idrivejunk** · 06-10-2014

The sizes are odd, the end of that manifold nipple is larger than the two pipe ends. I had to dig around the garage a little to find stuff that worked. The stock tees always split at the manifold end. Mine threw misfire and MAF codes, don't remember the numbers but I left it unhooked once and it was awhile before I noticed. One day I floored it and she missed and lit up the dash. Soon as I opened the hood I cussed when I saw that off.

**Scottydoggs** · 06-10-2014

Originally Posted by JayHerlth

It once upon was tucked back there, until I noticed it wasn't on the bracket and tugged on the loose line. Only to find tape on the end.

That would also explain my wot issue. Was getting a p0101 and p0102 error. Thought my maf was bad and causing it. Cleaned it, and still nothing. At around 4k rpm it just doesn't want to go past it.

the line with blue tape should run down the pass side fender and under the fuse box then into the wire harness and into the cars cab. it controls the air flow direction of the a/c and heat. i bet that stuff dont work, stuck on floor and defrost right?

you can buy them T's at advance auto.

**Scottydoggs** · 06-10-2014

Originally Posted by idrivejunk

The sizes are odd, the end of that manifold nipple is larger than the two pipe ends. I had to dig around the garage a little to find stuff that worked. The stock tees always split at the manifold end. Mine threw misfire and MAF codes, don't remember the numbers but I left it unhooked once and it was awhile before I noticed. One day I floored it and she missed and lit up the dash. Soon as I opened the hood I cussed when I saw that off.

i spit in the line and jammed it on the nipple under the snout. dude lube wins again lol

**idrivejunk** · 06-10-2014

Loog loob lol

**JayHerlth** · 06-11-2014

Originally Posted by Scottydoggs

the line with blue tape should run down the pass side fender and under the fuse box then into the wire harness and into the cars cab. it controls the air flow direction of the a/c and heat. i bet that stuff dont work, stuck on floor and defrost right?

you can buy them T's at advance auto.

Well, the fan blasts and only minimal amount of air will come out of the vents. AC 'works' it's cooler than the hot air, but not ice cold air. Boost gauge doesn't work still, I'm assuming it's from that T connector missing. I'll go to the auto parts store on Thursday or Friday when I have time to get some parts to make shift a T connector. If I fail, oh well. I'm still waiting on the connector to show up in the mail