Vacuum line help

Artyom

Member
Apr 11, 2024
32
0
8
USA
I was wondering if anyone could help with where my vacuum lines need to go. I’m not sure why the vacuum diagram on my hood and many other forums I’ve looked at all confuse me. Partly because the previous owners had a really complicated way they put together all the vac lines. However I had pulled them off to do some engine work and forgot how it all went together.

So attempting to follow the diagram I had finally gotten something put together. Now the car has a slightly low idle, and has a really bad hesitation when giving a slight amount of gas.

I’ve taken pictures on how I went back and tried routing things differently to hopefully solve it. Does this look right so far?
(PS: there is a trick flow upper intake on, and a different little piece that is after the throttle body which has 3 vacuum barbs.)

IMG_4872.webp

IMG_4873.webp

For context:
Green circle: is the hose coming from the canister purge valve. I can’t tell if the diagrams I’ve looked at say it goes on the throttle body vac. But some other diagrams say “man vac” which I’m guessing goes on one of the lower manifold vacuum barbs.

Yellow circle: is the hose coming from the top part of my PCV valve. It has a lower barb that had the big tube on it, then a top barb with a smaller tube (yellow circle).

blue circle: is the main vac tube on the vac tree labeled “S” and has a blue marking. Now I’ve see a photo with the blue marked tube on the large nub on the part after the throttle body, but other photos show it’s located under the upper intake manifold on the back part so I’m still sticking with that.

Red circle: is the fuel pressure regulator that is connected to the main vac line. the capped of part next to it originally had a red line for emissions stuff running to it. But I since tried swapping it to the part after the throttle body.

Now for the big PCV tube: that is running to the lower front side of the intake manifold. This is the only tube I remember that before I had taken everything apart, it was on the big nub on the part after the throttle body.

Now this is just a test, I haven’t been able to try this set up yet as it’s too late to try running the car. Is this how it’s supposed to go together? Sorry for all the confusion.
 

Post#4
(I realize there is some confusion probably due to what a previous owner has done, you just need to make sure all your components that need vacuum have it, and any connections arent left open.)
 
I’m in defeat. Tried a few different combinations and the car just really struggles still. I’m thinking its the intake manifold not being bolted down fully because the original bolts just wouldn’t grab their threads anymore. Not stripped but like they are too short now? I’m using longer bolts but didn’t cut them down a little so they would sit completely in the hole. The gasket also had a crack in it. So this could be just a massive leak from the intake manifold?
Quick note, when I mean not bolted down fully I mean this by 3 of the 4 corner bolts are slightly too long. So the head of the bolt isn’t snug against the intake manifold.
It all probably has to come off yet again as the valve covers that started this whole ordeal are still leaking.
 
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Where is your vacuum distribution block in all of this?

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Start here and work your way outward. Include any aftermarket gadgets in your brain (or on paper) in your checks so that you can figure out what's going on.



This to me, looks like a tap created for a vac/boost gauge. You got one of those? Included in that tap may be a small orifice restrictor, in the line.

It's a bit of a hack job but it looks like it should work. :shrug:
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that whole mess was to mimic the metal vac tree that came on the stock intakes. Looks like this.
IMG_4876.jpeg

Should I just get rid of that mess I have now and just route the main vac line to the manifold. I watched a video and got an understanding for how the whole vacuum thing works. But from what I’m seeing it should work?

Also, I cut the bolts down a little so they would fully tighten just to see if it would make a difference. It didn’t but thought I’d give it a try. However I’m noticing the tube on the top barb for the PCV is making a lot of noise. A vacuum noise, but doesn’t seem to be leaking. Pinching the tube makes it go away. Is it supposed to sound like that? Right now it’s plugged into the barb on the part after the throttle body. I just can’t seem to find where it’s really supposed to go as I can’t find it on any diagrams or pictures.

The vacuum tree/ block is on the driver side fender
IMG_4877.webp
 
I had enough time to try a few things, not sure if I found anything of use.
I pulled the EGR hose to make sure it wasn’t running at idle, no vacuum. Pulled the FPR hose and no fuel was leaking out of it. However I noticed that the pressure check valve on the fuel rail is very slightly hissing and leaking some fuel? Could this mean there is too much fuel pressure?
I also found that I can pull the connector to the IAC and the cars idle will not change, however unplugging the MAF sensor, the car does die. I was looking at some posts and apparently it should stay idling?
 
I haven’t been able to check the pressure. Should be around 40 from what I’ve been seeing?
I haven’t been able to go through all of it yet but some quick checks I was able to do. Like unplugging tps, maf, then SPOUT to see if the car still ran. And checking the egr and fpr vacuum lines. It just puzzles me how it ran fine after I replaced the gaskets, but I had to redo one because it was leaking pretty badly, then thats when issues started to happen.
 
The schrader valve in the fuel line can go bad just like the valve in a tire stem. They sell new ones and the same tool that removes the ones in a tire stem will work on the schrader valve.

Whole assembly:

Just the valve:
Victor valve core part number 22-5-00710-8

Tool:
Milton Industries Valve Repair Tool part number MILS445
 
I replaced the gasket in between the upper and lower intake. My next culprit possibly is I know I keep getting a code for the TPS sensor (121). I’ve replaced it and I don’t think you adjust the TPS on the 94 and 95 cars?? It never seemed to cause issues for me when it ran just fine. I do need to run codes again as when I took it for a little test drive the engine light came on twice.
Also thank you for that part! Much appreciated!