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Headers glowing Red after fast 90 install

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Old May 11, 2008 | 01:13 AM
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Default Headers glowing Red after fast 90 install

I installed my fast 90/nw tb today. When i started it the idle was around 2000-2500 rpm. Within 1 minute of idling i noticed the headers staring to glow red so i shut it off.

I re-checked the hoses and whatnot then i started it up again with the same effect - high idle, red headers. It threw 2 codes:

p0122 TPS/pedal position sensor A circuit low input
p0507 idle control system RPM high

I realize its running lean but i dont know why. One other thing, on the NW tb i got, the hole in the plate is between 1/4 - 3/8" wide. Is it supposed to be that big? Any help on this would be great.
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Old May 11, 2008 | 09:18 AM
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You've got a vacuum leak somewhere causing unmetered air to enter the combustion chamber. That's what's causing the glowing red headers and high rpm idle.

DO NOT RUN THE CAR ANYMORE TILL YOU FIND THE LEAK!! If you are running that lean you are going to cause engine damage. Recheck all of the intake bolts as well as the MAP sensor and throttle body bolts to find your air leak.
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Old May 11, 2008 | 02:34 PM
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The hole in the TB shouldn't be that big.
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Old May 11, 2008 | 05:09 PM
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Originally Posted by tacklebox
On the NW tb i got, the hole in the plate is between 1/4 - 3/8" wide. Is it supposed to be that big? Any help on this would be great.
That is the reason for your high idle but most likely not the cause of the lean condition.

Re'
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Old May 11, 2008 | 08:18 PM
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Well i covered up the hole on the tb blade and it made little to no difference in the idle rpm. the only thing it did was stop the headers from glowing red. ????? It doesnt make any sense but thats what happened. Could my fast intake be leaking internally?
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Old May 11, 2008 | 08:19 PM
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The lean condition is from unmetered air coming into the motor which makes sense since he just installed the new intake. The FAST intakes have been known to be a little warped and need to be fully tightened in the proper sequence to make certain there are no leaks.
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Old May 11, 2008 | 08:23 PM
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Well i did buy the intake used and it came shipped in 3 pieces which i assembled myself using rtv and a new inner gasket. I guess i'll have to pull the thing back apart to make sure.
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Old May 13, 2008 | 07:09 AM
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Did you use the button head valley bolts underneath the intake? If you didn't and left the stock bolts you've probably cracked the bottom of the FAST and that is where the air is coming from. Sorry.
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Old May 13, 2008 | 10:25 PM
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Yea I used the button head bolts
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Old May 14, 2008 | 03:00 AM
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What did you torque it down to, what sequence you follow?
-Joel
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Old May 14, 2008 | 09:27 AM
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If you are standing above the valve cover looking down at the manifold, it should be tight up against the head with no gaps. Look from both sides. Did you use RTV on the map sensor or just leave it as is; they are known to be loose.
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Old May 14, 2008 | 12:43 PM
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It sounds like a crack to be honest.
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Old May 15, 2008 | 10:27 AM
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Originally Posted by 2000Hawk
What did you torque it down to, what sequence you follow?
-Joel
I followed the sequence in the instructions on their website. As for what i torqued it to, I dont have an in-lb torque wrench so i'm really not sure. I made the bolts snug and tightened them down a little further. I didnt want to crack the thing so i didnt go crazy on it. Maybe it needs a little more? I'll check again when i get home from work.
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Old May 15, 2008 | 10:28 AM
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Originally Posted by Viper
Did you use RTV on the map sensor or just leave it as is; they are known to be loose.
I wrapped electrical tape around the nipple on it but i may try the rtv thanks!
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Old May 15, 2008 | 10:47 AM
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If you have cruise control that connects to the throttle body blade, you might want to take it off and see if that stops it. That was my problem.
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Old May 28, 2008 | 08:01 PM
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I was searching for p0122 code and found this thread....but did you get your idle fixed yet?

Originally Posted by tacklebox
I followed the sequence in the instructions on their website. As for what i torqued it to, I dont have an in-lb torque wrench so i'm really not sure. I made the bolts snug and tightened them down a little further. I didnt want to crack the thing so i didnt go crazy on it. Maybe it needs a little more? I'll check again when i get home from work.
I had the same problem after installing my FAST. The intake was leaking towards the back of the engine even after torquing it down in sequence to the correct specs. I went back over it periodically, like over a period of a couple of weeks lol and snugged the bolts up in sequence and the leak went away, idle went to normal.
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