Jeep Wrangler Forum banner

Idling at ~500, rumbling exhaust, CEL flashing, hatred and rusty nails

1K views 13 replies 9 participants last post by  demarpaint 
#1 ·
So this thread might be relevent (http://www.wranglerforum.com/f210/new-battery-now-wont-run-idle-properly-1851777.html) but my problem isn't/can't be correlated with a battery swap.

Today it was a bit colder in Colorado, but nothing like Winter. This morning my rig's engine took maybe a second or two longer to turn over, but all was fine until I ran out for lunch 5 hours later. Weirdness and rumbling coming from the right-rear.

Riding home (only two miles) the CEL would flash at about 1 Hz, turn off, stay solid, etc. It seemed to happen more during acceleration in first and second gear (6-speed manual). When I got home, the I took a quick peep under the hood and at the exhaust--which smelled weird, though I can't say I've taken a good whiff of it before.

There's a noticeable rumble-and-shake taking off in first/second gear, but nothing evil like a death wobble. I'm hoping I need an oil change, for which I'm well overdue, but paranoid something else is amiss.

As I mentioned in the title, too, the engine is idling low. Maybe too low. And this just happened: no new mods short of replacing dissolved battery lugs a few weeks ago--and tightening them solid--as well as adding a new stereo before that. I run a solar (50W) panel since I'm retarded and sometimes leave the lights or stereo on with the engine cut--rarely, though, but I did leave the lights on for a couple hours today... so, hmm--but I don't see why I'd have the problem unless, perhaps, my timing belt got jarred? Or my alternator is about to hit the other side of the dirt? God, I hope it's not the latter. Or spark plugs? I really don't know much about the under-the-hood stuff short of the battery,,, I've learned quite a bit, but I'm still a noob having only worked on it for two years.

Any smoking guns?
 
See less See more
#4 ·
I'd start w the simple and disconnect the battery for 10 minutes. Check all plug connections. Check any wiring or harnesses around battery. Check oil, radiater. Then reconnect.
 
#5 ·
Weird smell, and engine running poorly?
Sounds like you may have a sensor wire harness too close to the Exhaust Manifold or Exhaust Pipe. Check all of the wires and wire harnesses to ensure they are not contacting a hot exhaust or engine.
Some times it will take a while for this condition to reveal itself if these are not checked closely.
 
#6 ·
Thanks, my friends. I'm going to be doing electrical work on my jeep tomorrow morning, so the battery will definitely be disconnected. I'll check these things.

Could my spark plugs be going bad and adding to the trouble? I haven't put many miles on my jeep, but have done quite a bit of around-town driving--shitty mileage, but whatever--and I haven't touched them since I bought it used about two years ago. No idea what state the were in at the time.
 
#7 ·
\

What year and how many miles on the plugs? More info would be helpful. It could be a plug, a coil pack, if equipped, a bad wire or sensor. I'd check for codes, and disconnect the battery for at least half an hour, open a door or step on the brake after you disconnect the battery.

You could have a vacuum leak too. I had one drive me nuts! Good luck
 
#8 ·
Sorry for not posting codes. I will tomorrow... just been in the middle of projects and every time I notice me ODBII reader I think to do it, but get distracted,,, or yellow jackets happen.

About ~90,000. I bought at ~70k. I have changed the plugs and don't when, or if, they were last replaced.

If you don'f mind, what did fixing the vacuum leak run you?
 
#9 ·
If you don'f mind, what did fixing the vacuum leak run you?
A can of carb cleaner and a vacuum hose. I did it myself. I inspected all vacuum lines and connections looking for a smoking gun. When I didn't find any issues I sprayed all suspect spots with carb cleaner with the engine running hoping to hear a change in rpms indicating a leak. That didn't happen so I did a hose inspection again, and there was a split in a hose connecting to a vacuum tree. I missed it the first time, but was rushing. The vehicle wasn't a Jeep but the same troubleshooting process applies.

With regard to cost, it would be T&M. Worst case is they have to smoke test for vacuum leaks, locate it and make the repair if they can't visually find one. Before you drive yourself nuts looking for a vacuum leak I would suggest pulling all codes and resolving them first. There's a good chance if you have a stored code it could hold the key to your problem. I had no codes.

Good luck, I'm interested in the fix.
 
#12 ·
11 posts in and we dont even know what motor we are talking about Read codes. It will tell you what the problem is. My guess would be a crank position sensor or cam phaser.
Looks like profile says 2007 JKU so IF that is correct...3.8.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top