cruiser54

Make sure the rear grommet isn't swollen closed. Remove the hose from the intake manifold nipple and be sure the nipple isn't clogged.

Kris smith

Cruiser did the c101 pats night and chased grounds some of my Harness grounds had been fixed pins were tight cleane them and replaced the ground splice for the injectors and taped the harness in the good cloth tape we have at work. It runs better haven't had the high idle issue but we will see I still need to replace the o2 and the tps I have a very inconsistent throttle response. I'm gunna run a can of 44k next week see if that helps any

DESERTXJ206

Cruiser,

Today I replaced the TPS on the 88 and shes running good also. However it had a fluctuating idle and i noticed theres a hole on the throttke body letting air pass and when i plug it i get a amooth steady idle. Heres a pic of the hole.....





I noticed the set screw on the side in the 2nd pic was backed all the way out so i tightend it in (closing the hole off) and my idle is smooth and not fluctuating.



Is this bad to have the screw all the way in, what is the purpose of the hole?

89cherokee2gtmudy

My 89 cherokee is having very similar problems. Id have to check that screw as mine has a fluctuation in idle.

DESERTXJ206

The screw is a T25 torx bit. I tightened mine in until it stopped and it closed it off.

cruiser54

I'm so proud of you!! Great job!!

DESERTXJ206

Thanks. Whats the purpose of that screw on the side anyways?

cruiser54

It's the base idle air bleed. I'm not real excited to see you bottomed it out as that tells me you're getting air into the engine from somewhere else. I wonder if someone tampered with the butterfly stop screw. If that's the case, you'll have to adjust that, and then probably be required to back out the bleed screw.


Cruiser’s Renix Throttle Body Butterfly Adjustment

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. 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.

Revised 07/07/2012

Kris smith

Ok mine was running great till last night I got off the freeway and was idling at around 1200rpm and some times as low as 350-400 I guess ima go and buy all my sensors tomorrow. Tps CPs and o2 here I come

DESERTXJ206

Before you spent the money have you tested any sensors?

cruiser54

Skip the CPS for sure if $ is an issue. Be sure to adjust the TPS. O2 is probably due anyway.

DESERTXJ206

Im confused on how id be getting air elsewhere in the engine. The idle would kind of surge while just letting the engine run. Once I adjusted the screw closed or held my finger over the hole it would idle very smooth.

Should the engine die or something while i close the screw off?

There was some sore of silicone on the set screw itself when I adjusted it.

Kris smith

I haven't tested jack. I'd rather spend the money and get new stuff that will work and start there my CPs is jacked it is giving me intermittent issues with starting. I'm sure the o2 hasn't been done seeig as how Haynes recommends it be replaced every 80k. I don't know what the factory service interval is. Can I get a new tps and then adjust it and I need a new connector as well the po broke it and then zip tied it together its got a good contact an is tight but zip ties are trashy

cruiser54

Yes it should die. The silicone was put there if a dealer ever messed with that screw, after removing the little plug that used to be there.

Kris smith

Jeep has canceled the tps sensor but the parts guy gave me a part number too try to find a new one. What are the chances that the old one will be fine