So back in February of 2024 I was on the way to a Super Bowl party and when parked I smelled antifreeze. Come to find out it blew head gaskets. Did the repair and I’m now in the last stages of the repair. I’ve been stumped for about a week now trying to remember where all the boost/vacuum lines go. I’ve tried the diagram by the passenger headlight which did help for some but not all. I’ve tried the Haynes book but that’s so vague and actually doesn’t have anything for me other than some poor black and white pictures. I see I’m not the only with this issue so when I finally get it right I will make a YouTube video for others now or future who may run into the same issue.
Vacuum/boost line help!!
- Thread starter Noblel117
- Start date
In this photo I have a small coolant line laying by the valve cover. I’m confident that goes to what i believe is a heater core hose.then vacuum wise I have two small lines (which seem to be broken) one of them come from the passenger side fender and the other comes from the fire wall with some A/C lines. I also have one of the ends (I assume it’s one of the ends) on the fender wall. I don’t know where they actually come from or where they go. Definitely need help with them two
On this photo right by my hand has two lines and an electrical connection and based off the diagram on the car this is abbreviated to “EVR” the diagram shows one of them goes to the EGR which I deleted so the one with the 90 won’t hook up to anything. As for the other hose it shows that it hooks up to the “man vac” (clim cntrl) but doesn’t say where exactly to hook it up so I took my guessThe “man vac” with climate control is grey and has one of my vacuum line hooked to it (not 100% sure if it goes to that specific location on it) from the “EVR”
In this lovely photo my hand is on a line that from the passenger fender and I think it’s the fuel carbon canister line. I have that line going to the valve cover line. The valve cover line goes up into the (what I call) throttle body manifold inlet, just left of the grey square (about center of the photo) after that I have the bigger rubber hose to the left goes into the “man vac” This photo also shows the “FPR” going to the small inlet but I’m pretty sure that’s where it should be
So here I’m hold what my diagram calls the other “man vac” but instead of saying “clim cntrl” this one says “spd cntrl”First hose I wanna address is the one with no home on what i believe is called the wastegate actuator, comes out right where the missing inner cooler pipe is.
Also next to the missing inner cooler is another hose ( more by the oil dip stick right next to the electrical plug in) my cars diagram leads me to believe this is the “to dash vacuum” which would make sense because that hose enters the firewall by the driver side fender.
Now onto the “man vac” (it’s a mess) the 90 next to my index finger I think is labeled “water” on the diagram but don’t know what its purpose is. Just a breather vent maybe?
There are two open ends which I can’t find a match for and three others with hoses. One hose is a hard line and it goes from one “man vac” to the other. Then there’s a large rubber hose with zip ties on it and it goes up to the windshield wiper with no connection. Finally the third one is a rubber hose that turns into a small hard line that goes to the other “man vac” which I will get a better picture of and post it right below
The little line at the bottom of what I’m holding is where the third line goes. There’s also an open spot right by it needing a hose.Also in this photo the larger black with red strip hose doesn’t have a home and I’m unsure of where it belongs also.
I have quite the mess and have learned that taking pictures or better labeling things ends up being crucial to these bigger jobs that test the memory.
Here’s a final picture with everything in it. Thank you guys for your help, if there’s anything you need from me please ask. Also while I’m here I’m not sure where the OBD plug in is at so if someone would kindly throw that information in here that would be great! Thanks for the help and maybe soon I can start driving my car again!!
Under one of the white caps? That say something like “ARC/E?? Test”? I can’t remember the two letters after “E” hence my question marks.
Ahhh yes found it. Ok thank you for that. Now I just gotta figure out these vacuum lines
Thank you again!!
You never mentioned what year your working on, but based on the pics you must have a 89-92 (Teves brake system). The EVTM's have clear pic's in them & a good description of how each system/component works.
I know each year has slight variations though, I think 89 is the only year that use's boost bypass valve is 1 example. Do you know someone near you that has 1 that you could drive to or can come to you to compare?
Oh of course silly me. It’s a 1990 with a 5 speed. EVTM? Not sure what this abbreviation means. I don’t have any other thunderbirds near me, I’ve tried asking people on Facebook market place if they would be kind enough to send pictures but I haven’t found anyone willing to take the time.
coupe crazy
SCCoA Member
Electrical and Vaccum Troubkeshooting Manual. I assume you are the one who did the work. Why didn't you label or take pics before unhooking everything? Not a criticism, just would have made your life 1000 times easier and a good practice.
coupe crazy
SCCoA Member
You can find them on ebay for about $25. This is a Ford issued manual. 
The coolant line in the first picture goes to the throttle body. There is a port along the bottom of the throttle body that the coolant runs through, and it connects to a line that runs along the intake manifold. The vacuum lines in your second pic are for the EGR, so if you have deleted that, you can just block off the line that would have gone to the EGR valve. Also in that pic you can see the vacuum line that goes down into the passenger fender. That line attaches to the piece of line coming out of the firewall, which is used for the mode door selection for the HVAC behind the dash. The line in the 3rd pic is the EVAP line. The purge valve is on the charcoal cansister, so that just has to go to any vacuum source before the supercharger.
Your “main vac” line is the main vacuum manifold. You’ll see it connects by the hard plastic line to the similar grey piece that is toward the center of the firewall. Those lines go up along the firewall under the wiper cowl. Those get vacuum source from the large hose to the right of your hand in pic#3 that connects to the grey piece and then disperse vacuum out to various other things. One note on the black piece, some of the ports are for vacuum and some are for the windshield washer, so don’t mess that up or you’ll be sucking washer fluid into the engine. I believe the 2 open ends are for the washer fluid, and the hose for that runs along the driver’s side frame rail and comes up by the brake booster.
Once you have all that setup, it is really just a matter of hooking things up in a way that everything fits and reaches. The line for the boost gauge is the one on the driver’s side of the return plenum which you already have connected, and the line for the fuel pressure regulator is on the back of the return plenum. Both of those must go to those locations because they need to see vacuum and boost, but all the other ports are only getting vacuum, so as long as it connects, it will work.
Your “main vac” line is the main vacuum manifold. You’ll see it connects by the hard plastic line to the similar grey piece that is toward the center of the firewall. Those lines go up along the firewall under the wiper cowl. Those get vacuum source from the large hose to the right of your hand in pic#3 that connects to the grey piece and then disperse vacuum out to various other things. One note on the black piece, some of the ports are for vacuum and some are for the windshield washer, so don’t mess that up or you’ll be sucking washer fluid into the engine. I believe the 2 open ends are for the washer fluid, and the hose for that runs along the driver’s side frame rail and comes up by the brake booster.
Once you have all that setup, it is really just a matter of hooking things up in a way that everything fits and reaches. The line for the boost gauge is the one on the driver’s side of the return plenum which you already have connected, and the line for the fuel pressure regulator is on the back of the return plenum. Both of those must go to those locations because they need to see vacuum and boost, but all the other ports are only getting vacuum, so as long as it connects, it will work.
Awesome!!! I will let you know how it goes soon. Gonna be hard to fall asleep now!! Super eager to hook it all up!! Thank you for the help I’ll update before next week