Low idle, rough idle, randomly doesn't start....

**BucketOKarma** · 05-20-2011, 18:04

This is for a 2000 2.5L Wrangler TJ:

Okay, so I have had this "no start" problem ever since I bought the jeep. Randomly (a couple times a year) the volts look good till I go to turn it over, then nothing, not even a click of the starter. I have cleaned all the grounds, and terminals, and even got a new battery once. Once I get it started everything runs fine, and usually will start right back up, no problem when I park it somewhere for a few minute, and sometimes once I get through that day, it'll be good for a few months...

I have also been having a ticking sound from under the hood. After dealing with an exhaust leak for about a year, I put on new headers, and that sound is completely gone. The ticking is relatively new though, and I KNOW it's not exhaust, the sound is completely different. It does quieter after running for a bit, and is usually louder under load in third and fourth gear than other times, although it is pretty loud upon start-up weather you rev it in neutral or try to take off right away. It sounds like other cars with timing issues, but since I know it can't be timing, I'm guessing distributer?

The reason for the backstory is that the failure to start problem happened again today. I ended up pop-starting it down my driveway, first start-up was okay till I had to let off the throttle, and it idled down to a stall. The second time, it almost did the same thing till I revved it back up and took off down the road.
On the road, the ticking sound was louder than ever, but aside from that, it ran like normal till I reached a stop sign. The jeep threatened to stall again, so I made the stop real quick and went on to the gas station.
When I went to park at the gas station, the rpm dropped down to 500 and it idled rough. Rather than turn it off on flat ground where I would have problems pop-starting it, I left it running and hoped it wouldn't stall out while I was inside.
I came out and it was still running in the same fashion (low and rough idle). As I pulled out, the ticking (not knocking) was just as loud as ever. I drove it home without incident, parked in my spot and sat there for a minute. Absolutely NOTHING out of the ordinary. No rough idle, no low idle, no ticking, no shuddering, all the gauges were right where they should be, Fawking NOTHING!

What the Hell??!?

Anyone know what the [email protected] is going on here?

**GunsUp** · 05-20-2011, 23:08

The best first step would be to get some decent wiring diagrams. I'm not familiar enough with TJs to know what is connected to what or where. It's obviously at least partially electrical. My guess is that it'll be multiple problems. I'll see what I can round up while I'm at work tomorrow morning. (Auto parts stores are generally quite slow until about noon on saturdays)

**gearhead1985** · 05-21-2011, 01:35

do you have a cel

did you do any mods to the motor

**afjeep** · 05-21-2011, 08:39

i'd check your CPS or idle air control for the idle problems. is it throwing a code at all? as for the knocking, i had the same problem when my lifters locked up and one of them was just smacking the cam every turn. got really bad before i figured out what it was. might check those and see what they look like. if its the problem you'll see the damage. hope its not.

**warrior** · 05-21-2011, 16:04

Check for vacum leaks/ Map sensor/coolant temp sensor.
For lifters noise, Pour a can of "Marvel Mystery Oil" in you oil pan and drive it for
a couple of days then change oil. What SAE oil are you using??

**JoeySnow70** · 05-21-2011, 16:35

Originally Posted by afjeep

i'd check your CPS or idle air control for the idle problems. is it throwing a code at all? as for the knocking, i had the same problem when my lifters locked up and one of them was just smacking the cam every turn. got really bad before i figured out what it was. might check those and see what they look like. if its the problem you'll see the damage. hope its not.

I had a similar situation with my TJ my IAC was sticking due to carbon build up. Tore it apart, clean the housing with carb cleaner, reasamble it with some white lithium grease.... No problems since.... Wirh idle that is......

**19delta** · 05-21-2011, 18:51

sounds to me like the ticking sound could be "valve slap". can be caused by carbon build up more times than not, but sometimes it could be that the lifter(s) or even the valve retainer could be going bad. which an open valve can cause a low or rough idel. as for the starting issue i know what your going through. i had a 05 mustang gt that did the same thing. i narrowed it down the wire harness by moving it around. bad thing was it didn't do it all the time so when i tried to have it replaced under warrenty, naturally the dealership said there was nothing wrong with it. as for the engine problem, if i were you, i would have that thing looked at asap to save yourself a massive headache with a busted engine later down the road.

**BucketOKarma** · 05-21-2011, 20:50

Alright thanks... I'm not one for taking engines apart, so I don't know even what to look for if I do get it apart (litters, valves=??). If it is carbon build up, would a few WOT runs in second and third gear clean it out? I ask because that's what they tell you to do for the "cold carbon rap" on the northstars, wondering if an engine is an engine and therefore the same would apply here?

Any links for a step-by-step going through the engine with pics? So when I am sitting in my dirt driveway with my wrenches, I don't just start turning bolts that I shouldn't because they LOOK like something that belongs to the engine. I hate sounding so pathetic, but before this jeep I thought "PMCS" meant "Park the Mother and Call the Shop". I have worked on everything but the axle gearing and headers myself (I had very little to do with the sye as well, but I was there and did do some of it), but I have not needed to even so much as look at the engine itself aside from oil changes and the new alternator I put in a couple years back.

My jeep as had a lot of work done in my driveway and in the driveway of friends, but those things are "simple" items related to building. Engine work seems more daunting for some reason.

**19delta** · 05-21-2011, 23:29

running high rpm can clean some stuff out of your engine, but it's not like a deisel engine. plus you run the risk of it comming apart totaly. best places to look for an exploded view of your engine is in chilton book of looking online, plus the steps to remove the head to inspect the valves, lifters and pushrods. though when you do dig into it you will need to buy an upper engine gasket kit. if you got a six cylinder in yours with a cast iron head, be best to have some help getting it off. when i did mine it was pretty heavy and wished i had an extra set of hands. another good thing for you to do is if you have any freinds that are good with engines to have them help you out. take pics of things that seem complex to you before you take them apart and do take some notes on what goes where. with the chilton you will have the torque seqence and specs for everything, and a good rule of thumb to remember when you take off a head. to have a long straight edge to lay on the bottom of the head to check for warping. if i were there i would have no problem in helping you out with this to get you back on the road

remember to drain the coolant before you start!