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Old 09-18-2018, 12:29 PM   #1
EivlEvo
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Default Adjusting the idle thumb-screw on 2.2 TB?

Squad.

About a month back, I swapped in my LH 2.2 TB because my 2.4 TB had a leaking shaft seal that I couldn't get right with parts on hand.

This one has the adjustable thumb screw/knob. Does it use a set screw or something? Mine won't budge. I saw an allen hole in it, but it wouldn't do anything without slipping in the hole.

What am I missing? Turn harder? Where should I lube?
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Old 09-18-2018, 12:40 PM   #2
dl242gt
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Is the passage blocked by the screw being closed all the way? Maybe it's jammed closed? I would try some penetrating lube or silicone spray on it and try unscrewing it. There is an oring on it. Make sure that is in good shape when you remove it.
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Old 09-18-2018, 01:00 PM   #3
EivlEvo
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Blast. I can't imagine it's all the way screwed in... the idle is probably only 500 without the IACV. But I haven't had the time to nerf the 2.4 ECU idle controls to check it tbh. It's also just a band aid right now. I have my MS2... just need the time to study and tune.

To that end, the screw functions as a bypass passage, or does it physically move the throttle plate? (Just need to know where to look for the other end to lube up)
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Old 09-18-2018, 01:13 PM   #4
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The thumb screw adjusts the amount of air bypassing the throttle plate. The assembly comes off with 2 screws.

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Old 09-18-2018, 03:10 PM   #5
dl242gt
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Nice picture. That o ring is the one that causes sneaky vacuum leaks. Back when I had my kjet 79 242 it did it to me.
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Old 09-18-2018, 03:19 PM   #6
EivlEvo
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Superb. Thanks!
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Old 09-18-2018, 04:46 PM   #7
EivlEvo
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So wait... does tightening it allow less air to bypass? Thus... "decreasing" idle?
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Old 09-18-2018, 04:48 PM   #8
Lord_Athlon
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The idle is controlled by the IAC on 2.4, and its controlled well. How about you just leave it alone.
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Old 09-18-2018, 04:57 PM   #9
EivlEvo
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Quote:
Originally Posted by Lord_Athlon View Post
The idle is controlled by the IAC on 2.4, and its controlled well. How about you just leave it alone.
I intend to leave it alone. I'm only using this TB because my 2.4 one leaked and I had this one on hand. I'm addressing boost leaks right now and since I have a dumb size of injector (577s) the car stalls on clutch in. I have already had two long threads about it. It's 100% a vac/boost leak. But I haven't isolated it yet. I need to eliminate variables. This is how that works.
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Old 09-18-2018, 05:18 PM   #10
dl242gt
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Quote:
Originally Posted by EivlEvo View Post
So wait... does tightening it allow less air to bypass? Thus... "decreasing" idle?
From what I recall with LH2.2. it is used to set the base idle and then the iac motor handles regulating that. That is why I asked because yes tightening allows less air.
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Old 09-18-2018, 05:44 PM   #11
Lord_Athlon
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Quote:
Originally Posted by EivlEvo View Post
I intend to leave it alone. I'm only using this TB because my 2.4 one leaked and I had this one on hand. I'm addressing boost leaks right now and since I have a dumb size of injector (577s) the car stalls on clutch in. I have already had two long threads about it. It's 100% a vac/boost leak. But I haven't isolated it yet. I need to eliminate variables. This is how that works.
In that case you should just screw the idle adjustment all of the way in.
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Old 09-18-2018, 11:38 PM   #12
EivlEvo
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Yeah ok this is good info. I'd bet I'm gonna need to replace that o ring. We'll see where this leaves me leak wise this weekend...
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