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SuperNewbie
1995 Thunderbird LX 4.6 red
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Hello,
Congrats on the Bird! if it's the one that was for sale in Houston, I almost bought that one, but I found a stock one down here and for a bit less so I went with that one. I liked the color the PO painted your car!!
Again congratulations!!

I am back after a very long time. I no longer have the 1995 or 1996 Thunderbirds. Me and my wife were missing them so we decided to look around for another MN12. My wife saw this green 1994 T-Bird and had to have it. It has 57,000 miles and the previous owner did "the PI Swap" to it.

Now I am doing a lot of research to make sure it involved with this swap. It runs fine except when it is cold the idle drops so low it stalls. This symptom only lasts for about 30 seconds.
I did find unused ports on two vacuum trees. I connected the climate control line and plugged the rest. I a 1994 Ford Electrical and Vacuum Troubleshooting Manual in the trunk, that is nice but photos of how vacuum lines run along the firewall would help too.

Good to be back.
Rich
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Discussion Starter · #23 ·
Congrats on the Bird! if it's the one that was for sale in Houston
Thanks. Yes it is the one in Houston. I showed the ad to my wife and she said we should buy it. I was shocked, she never said that before when showed her cars for sale.
 

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1996 Thunderbird LX
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Yeah, it's hard to see what's going on. Yank the air intake tube and poke around a little, it's much easier to see the routing with that out of the way. The EVAP is a plastic hard line that runs along the top of the passenger side valve cover from the back of the plenum, then jogs across to the passenger shock tower and goes into the inner fender along the frame rail.

Here's a pair of images - one that I annotated to help show what and where, then another without the annotations so it's easier to see everything.

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Looks like my hardline is broken in multiple places. My idea of getting brass tubing is starting to look good. I just need to bend it without kinks.
 

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It is 1/4" OD. I suppose you could just use 1/4" fuel hose to replace a broken section of plastic line, since that is what you would use to connect the plastic lines together anyway. Would have to zip tie it in a couple places to hold it in place.

Al
 

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Discussion Starter · #27 ·
Need help decoding this tag.
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Super Moderator
1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Sequence number 23,420, rolled off the line on November 18 of 1993.
 

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Discussion Starter · #29 ·
It had the premium audio. Found the amp in the trunk. I want to pull the back seat. Hoping to find some Wacky Packs gum.
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Discussion Starter · #30 ·
Ah Ha! I found the lines from the PCV valve. One goes inside the fender, the other has two red lines and is not connected to anything. Basically a road draft tube lol.
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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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The one that goes down the side in the 2nd pic is for the EVAP system (goes to the charcoal canister and purge flow valve/sensor in the fender under the headlight). But the red lines should be for the FPR and EGR hardware.

It looks like they connected the PCV valve to the EVAP line coming from the gas tank. Oh boy!
 

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1994 Cougar XR7 DOHC/5-Speed
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The one going inside the fender is the EVAP line, it shares the tree on top of the PCV valve on 94-95s, so it’s fine to keep it there but the second plugged line off the tree needs connected to manifold vacuum.

The red lines are what remains of the original 94-95 EGR/FPR lines, I don’t know what they were thinking there lol
 

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Discussion Starter · #33 ·
Yep. I was looking the photo diagram Brandon posted (thank you!). That red set of lines doesn't belong on the PVC, it goes to the first port on the TB. Oh boy indeed.
 

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1994 Cougar XR7 DOHC/5-Speed
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Yep. I was looking the photo diagram Brandon posted (thank you!). That red set of lines doesn't belong on the PVC, it goes to the first port on the TB. Oh boy indeed.
It looks like the EGR/FPR lines were rebuilt using universal hoses and a T fitting in your diagram, that layout is fine, as is using the port they’re attached to. There’s no rule to which port is being used on the plenum, they all pull the same amount of vacuum, so in the case of the PCV/EVAP just run a line from the plugged port on the valve to the plugged port on the plenum
 

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Discussion Starter · #35 ·
I ran a hose from the PCV to vacuum and connected the EGR / FPR to the first port using the red vacuum lines that were connected to the PVC.
It started right up and the idle RPM did go up (900+), so I adjusted the idle down. Overall it is better but not perfect. I noticed that on start up the RPMs are hunting. Thinking the IAC valve is all coked up? It looks pretty old. My 89 mustang acted just like this.

Also took the headlight tint off. The car is a little happier now.
Gave it a little gas and it made two stripes.
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Discussion Starter · #36 ·
Just did a cold start and it is behaving perfect. No more stalling after tapping the gas pedal.
A big thank You to all that helped me.

I pulled the back seat and found a 1995 penny, a french fry fossil, a blue thingie and a ticket for free pancakes. Just in time for Easter. Joy!
42641
 

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Discussion Starter · #37 · (Edited)
I notice something odd with the Kiwanis card. What the heck is a "Orenge"? lol.

Anyway. I still have the cold stall when i tap the gas. i disconnected the the wire plug and it made zero difference to the idle. I checked the ohms on the IAC and it is 11 ohms. I checked the TPS and set it to .98 V and no change.
The IAC plug is getting power too. My 2002 Crown Vic starts cold with higher revs then settles down. The T-Bird starts with very low revs. I still feel the IAC is a dud.
I even took the IAC off and it is not coked up. I checked the manifold vacuum and it read 20 inches.
Scratching head.
 

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SuperNewbie
1995 Thunderbird LX 4.6 red
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3,146 Posts
Just did a cold start and it is behaving perfect. No more stalling after tapping the gas pedal.
A big thank You to all that helped me.

I pulled the back seat and found a 1995 penny, a french fry fossil, a blue thingie and a ticket for free pancakes. Just in time for Easter. Joy!
View attachment 42641
$5.00 pancake breakfast?? I'm in..I bet they would honor the price if you have the card...
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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If the IAC is toast, usually it manifests as the car starting then immediately stalling with no associated sputtering. The way to be sure is to crack the throttle slightly when starting; if it runs (better) slightly off idle, the IAC is a suspect.

For the first few moments after a cold start, the PCM is operating in open loop - relying only on feedback from the MAF sensor to set the fueling while the O2s warm up. Is the original MAF on the car? Has it been cleaned recently? If it's still running lean, that could explain the rough idle and stall as soon as you tap the throttle.

With all vacuum leaks addressed you can pull the PCM fuse or yank the battery for a couple minutes to reset the KAM, to force the PCM to relearn the ISC_INTEGRATOR values for the IAC.
 

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Discussion Starter · #40 · (Edited)
If the IAC is toast, usually it manifests as the car starting then immediately stalling with no associated sputtering. The way to be sure is to crack the throttle slightly when starting; if it runs (better) slightly off idle, the IAC is a suspect.

For the first few moments after a cold start, the PCM is operating in open loop - relying only on feedback from the MAF sensor to set the fueling while the O2s warm up. Is the original MAF on the car? Has it been cleaned recently? If it's still running lean, that could explain the rough idle and stall as soon as you tap the throttle.

With all vacuum leaks addressed you can pull the PCM fuse or yank the battery for a couple minutes to reset the KAM, to force the PCM to relearn the ISC_INTEGRATOR values for the IAC.
The idle is fine smooth as silk and tapping the gas it responds normal and with no hesitation. The the throttle is cracked slightly via the idle adjustment screw. That would explain why I and to adjust it down to achieve 0.98 V at the TPS. At this setting the idle was too low to stay running. So I set the idle screw back to were it was and this also caused the TPS to read 1.03 V.

The IAC is a 96-97 and looks to be Motorcraft.
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The Mass Air has a 1994 part number "F4..."
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