Crimmy

Hey guys so ive been trying to button down my idle issue. Ive replaced all vaccum lines, cleaned IAC, replaced TPS. Nothing helped until i replaced the tps which was a very minor improvement. It gave me better throttle response but did not help with the idle issue.

The idle surges down or up intermittently. And for the first time today the jeep stalled on me. Id driven about 2 miles to the grocery store just fine. Parked and when i started up and put it in drive made it about 10 feet and it died and the only reason i knew is because i went to take a turn and the power steering and brakes were gone. It made no weird sounds and i honestly couldnt tell it died on me.

One other problem ive found is that the bracket that holds the alternator has broken off at the top bolt. Ive noticed when the idle goes from normal to rough that the voltage drops from 14v down to 9-10. Im wondering if the alternator could be shifting and losing power causing this issue. Is this possible?

I immagine if it was spark plug related id have misfires and backfiring and things like that which it doesnt do at all.

Crimmy

Oh wanted to add a lil detail i left out. It stalled 2 or 3 times on me. Drove a couple feet and it just died. Started back up with no problem whatsoever. The second time it died before i even got it into gear so i had my foot on the break and gave it gas and shifted out of park almost immediately and revved hard a few times. The idle dropped and it died again. Started it up switched from brakes to gas shifted out of park and it didnt give me any trouble from there to home.

So ive been looking around and lots of people with this issue are saying crankshaft position sensor. Can that cause idle issues too? Or could this be related to the broken alternator bracket and possible alternator movement?

salad

How old is your battery? Are the cables and terminals caked with corrosion?

Also I'm assuming you have a 1992 XJ with 4.0L.

Mikeythrash

I got everything replaced except my CPS and it's idling bad and I have 2 cylinders misfiring coming up on the codes I check.i am replacing my CPS this weekend if that fixes my issue I'll let u know.but my voltage doesn't drop like yours at least I havnt noticed.so may be multiple problem CPS and alternator and maybe bad battery terminals

Crimmy

No, sorry i didnt specify. Thats my old xj. This is an 89 xj. Not able to pull codes on it.
And thanks Mikey. Im not getting any misfires i dont think. Just surging rpms and most recently stalling out while driving. Ive been going through cruisers renix tips and they dont seem to be helping the issue any.

The battery terminals arent corroded but they look like they have been gnawed on quite vigorously. And the battery i believe is only about 2 years old.

freegdr

Sounds more like IAC issue to me.

Crimmy

OK ive got an extra i grabbed from the junk yard ill clean it up and try swapping them. See how that goes. Thanks freegdr.

freegdr

Worth the 15 minute it take to swap it . Im sure Cruiser54 got a test for it in his portfolio . I cant find one on the mighty Interweb yet.

Crimmy

Ok cleaned up the IAC i got from the junk yard and some other connectors i found hidden beneathe other junk. Pulled off distributor cap and the cap was clean but the rotor had black gunk on it so i hit it gently with a wire brush real quick.

Jeep refused to start because i forgot to plug something back in plugged it in fired up after a few moments and the idle at first was very very rough but i drove it around the block a few times came back and parked it and it was stable IT WAS STABLE! Mostly. It at least wasnt dropping so low that the whole jeep was shaking violently. I dont know if it will stall out or not. But for now this is a huge improvement. Thank you for the tip freegdr i had already cleaned the IAC that was in there so i had ruled that out.