Okay. Let’s start from scratch.
First off, that’s not an idle adjustment screw. It’s a throttle butterfly stop screw. It’s purpose is to allow the butterfly to be as close to completely closed as it can be without binding or wearing into the throttle body. It was never intended to be adjusted in the field. But, Uncle Bob didn’t know that, did he?
Engine off. Back off the butterfly stop screw with a 3/32″ allen wrench until the butterfly is completely closed. Now. turn the screw in until the FAINTEST movement of the butterfly opening is detected. If you have a .003″ feeler gauge, or something that thick as measured with a caliper, use that to set the clearance. We’re talking sticky note paper here.
This can be done more easily with the throttle body removed. If you remove the throttle body, be sure to replace the gasket underneath it after thoroughly cleaning the old one off.
Readjust your Throttle Position Sensor.
7 thoughts on “Renix Throttle Body Butterfly Adjustment”
I got an 87 Cherokee chief from a guy from Craigslist and no clue what he has done to it yet. It idles really rough and I can see tool makes around the screw on the TB so I assume he tried to fix the issue by adjusting that. My question is should the screw be touching the plate or should there be a slight gap? Also it seems the plate is a bit loose and when you push the pedal it leaves a gap, but you can push it and it will close the gap…kind of like a worn out hinge that won’t close all the way unless you manually do it…sorry for the long comment.
First off, don’t apologize for a great question!! The screw should be touching the stop. At this point, who knows how worn things are from having it out of adjustment. Take it off and inspect it closer. While it’s off, clean the throttle body and IAC. Make the proper adjustment and see how it feels then.
thanks for the reply!! I will be taking the TB off this weekend and will take a look once it’s out. It seems the guy I bought it from had a spark plug wire that was missing the inside so that might account for the rough idle. I started by cleaning the TB itself and it definitely helped with the idle, I had forgotten to mention when I push the gas pedal it wants to stall, but now I can rev it up and it drops down to about 0 rpm wants to stall than recovers. I think the TB might be the main issue for that. Thanks for the help! For the life of me I could not find anything that explained how close the plate needed to be on the Internet
Hey cruiser. Uncle previous owner opened this up big time. That explains, probably, the high idle I always got even after cleaning TB and intake. I followed your instructions and set the butterfly to slightly open (detect tiny bit of opening and set it). The motor is running great with a nice idle but it has stalled twice now coming to a stop. Should I be patient and let Renix computer adjust over several days of driving, or open the butterfly a tiny bit more? I’ve done almost all your steps except for indexing the distributor.