I'm at a loss...I have a 90 cherokee renix 4.0 with a ax-15 (originally a auto) open cooling.rig has been mollested bringing it back to life but I have been having a low idle issue I can't put my finger on. It has a rough start if cold but when it fires up it will idle fine (about 900rpm) but after a minute or two the idle will drop to about 300 for about 5 seconds and the jump back up and will idle steady at about 600rpm. Took it for a little drive yesterday (did the same as discribed above on warm up) for about 3 miles and when I got back and put it in N it would idle at 3 or 400. What gives?? I have recently replaced my iac, tps is adjusted properly, grounds have been cleaned up, checked and rechecked for vac leaks. I have my suspicions about the O2 sensor but not sure (just recently caught the automotive bug) any advise or suggestions will be greatly appreciated. Thanks in advance

 

Begin by going to www.cruiser54.com and doing Tips 1,3,4, and 5.

 

good lookin out..I have not done #5 yet!! Website bookmarked (I'm sure I'm not done with it yet) and I will get my volt meter out ASAP.

 

excellent plan!!

 

So I got the volt meter out on the sensors...the coolant temp sensor and map sensor were both at .04 ohms idk wether or not that is tolerable?? But the iac was diff. I got readings anywhere from 10.0+ to about 1.00+ but it was jumping all over the place

 

There is no test for the IAC.

do Tip 5!!

 

ok sorry I was rushing and got confused about the procedure. Did the test at the tps and got 4 ohms. More will be revealed but daddy duty calls lol. But thanks again for the help would never have gotten as far as I have and wouldn't ever finish my project without this forum. and u C54 specifically! Your site is like a renix manifesto haha!!

 

Any questions, post them up. We're not gonna make fun of you. LOL!!!

 

I hooked the volt meter back up and started jiggling around on wires and when I came to the dipstick ground I got a jump from 4 to 6+. Took a closer look at it and the connection where the wires junction into the bare cable look pretty tore back. Im going to do tip #1. But my question is, would it be beneficial to replace that bare cable with something different? Like a 4g cable?

 

Is your battery negative cable at the dipstick ground?

 

No it's on the bolt just in front of it

 

There should be about 3 wires on that dipstick tube stud.

 

I have a ground cable going from the terminal to the engine and another going to the radiator mounting bolt right by the battery

 

That is good.

but, at the dipstick tube stud, you should have 3 small gauge black wires with eyelets on them under the nut.

 

on mine it has a cable that is connected at the dipstick and then on the other end IOC that cable is a splice with a few wires merging into that single cable. All black wires one or two might have had a stripe