Throttle Body screw

jovian · Jul 14, 2016

1990 Renix, 4.0L stroker, with AW4 auto.

I have been having high idle problems at start. I cleaned my throttle body, manually and i noticed an adjustment screw on the drivers side that allows or restricts air, to an air passage, that goes from the top of the body to the throat, below the butterfly valve. It is in parallel to the IAC.

I have searched the internet and these forums and have not found any reference to this adjustment...

What is it for and how to adjust?

Thanks in advance, Vic

old_man · Jul 14, 2016

You should never have to adjust it. The IAC should handle the adjustment just fine. If it doesn't, you most likely have other problems.

High idle is commonly caused by a vacuum leak. On vehicles that have the vacuum canister mounted behind the right front bumper, the hard plastic line that runs under the battery is notorious for breaking.

Ecomike · Jul 14, 2016

LEAVE IT ALONE!!! It is not the drone you are looking for. Since the computer and IAC control the idle air flow rate assuming uncle Bob has forked with that screw or the butterfly plate throttle screw adjustment, and assuming there are no vacuum leaks ANYWHERE ( There dozens of usual vacuum leak suspects on these jeeps), then the Computer and a good clean throttle body and working IAC will control the idle speed, unless one of the sensors like the TPS or IAT are giving the computer bad data, or have a bad ground.

jovian · Jul 14, 2016

About the IAC, does it open up all the way whenever you turn off the engine?

old_man · Jul 14, 2016

No, see your PMs

xcm · Jul 15, 2016

Ecomike said:
assuming uncle Bob has forked with that screw or the butterfly plate throttle screw adjustment

SO true..

Ecomike · Jul 15, 2016

Edited / correction

Ecomike said:
LEAVE IT ALONE!!! It is not the drone you are looking for. Since the computer and IAC control the idle air flow rate assuming uncle Bob has NOT forked with that screw or the butterfly plate throttle screw adjustment, and assuming there are no vacuum leaks ANYWHERE ( There dozens of usual vacuum leak suspects on these jeeps), then the Computer and a good clean throttle body and working IAC will control the idle speed, unless one of the sensors like the TPS or IAT are giving the computer bad data, or have a bad ground.

cruiser54 · Jul 16, 2016

Start here, in case Uncle Bob left his mark:

http://cruiser54.com/?p=94

Throttle Body screw

jovian

NAXJA Forum User

old_man

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Ecomike

NAXJA# 2091

jovian

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old_man

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xcm

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Ecomike

NAXJA# 2091

cruiser54

NAXJA Forum User

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