2002 4.0 Rough/High Idle When Cold - JeepForum.com

 
LinkBack Thread Tools
post #1 of 12 Old 11-10-2008, 02:00 PM Thread Starter
peeweeXJ
Registered User
2002 TJ Wrangler 
 
Join Date: Nov 2004
Location: Gillette, WY
Posts: 1,281
2002 4.0 Rough/High Idle When Cold

My TJ has about 100k miles on it. And the Idle/startup blows compared to my 200k XJ.

No codes

It usually has the poor idle when it has been sitting for 15 hours+ (the length of time I am at work)

I will start it up and it will stumble/misfire on it's way to it's high idle.
It will idle at 1k rpms, until it warms up. The engine will occasionally try to idle down, but then it starts to stumble over itself, and goes back up to 1k.

If I start driving when it's cold, I will push in the clutch, and the RPM's will hold at what they were, or even go up slightly, then slowly start going back down to 1k.

I did clean the TB/IAC after this all started, but nothing changed.
Plugs are perfect.
Have run a couple tanks through it, with different octanes, from different stations.



I also have a related/unrelated? ticking noise that comes and goes when cold.
The ticking will increase with RPM's, and seems to quiet down (not disappear) when the engine gets to running temperature.
I will cruise down the road at 1500 rpms and the ticking will vary in loudness.
You can hear the ticking at idle in the cab with the radio off. You can hear the ticking at high RPM's with radio on, which is really annoying.
If I start the engine up cold, and the ticking is not there, it will show up if I rev it really high.
It has also been the other way around, where I start it cold, and it's ticking, and I'll rev it up really high, and the ticking will go away.
It has the correct/right amount oil, and I have run Rislone and ATF through it. Clean Mopar filter too.
I have also checked exhaust bolts.

I have taken a automotive stethescope to the engine and could not locate the ticking. Sounds like valvetrain though.

Could the idle problem be caused by a bad TPS or IAC? Maybe CKP?

Thanks for the responses

btw- this is not normal for a Jeep, if that's all you have to say.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
peeweeXJ is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old 11-10-2008, 02:18 PM
PJL
Registered User
1998 TJ Wrangler 
 
Join Date: Aug 2006
Location: Schenectady, NY
Posts: 1,350
I had a similar problem with my idle. No ticking, though. I replaced the TPS and the IAC and it was fine after that.

It's not enough to bash in heads, you've got to bash in minds.
- Captain Hammer
PJL is offline  
post #3 of 12 Old 11-11-2008, 01:45 PM Thread Starter
peeweeXJ
Registered User
2002 TJ Wrangler 
 
Join Date: Nov 2004
Location: Gillette, WY
Posts: 1,281
So you replaced both of them at once? So you really don't know which one fixed it?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
peeweeXJ is offline  
post #4 of 12 Old 11-12-2008, 11:34 AM Thread Starter
peeweeXJ
Registered User
2002 TJ Wrangler 
 
Join Date: Nov 2004
Location: Gillette, WY
Posts: 1,281
I will try and get a video soon.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
peeweeXJ is offline  
post #5 of 12 Old 11-12-2008, 11:56 AM
Wif
Registered User
 
Wif's Avatar
2004 TJ Wrangler 
 
Join Date: Nov 2004
Location: Just north of Calgary, Alberta, Canada
Posts: 2,990
Quote:
Originally Posted by peeweeXJ View Post
My TJ has about 100k miles on it. And the Idle/startup blows compared to my 200k XJ.

No codes

It usually has the poor idle when it has been sitting for 15 hours+ (the length of time I am at work)
I will start it up and it will stumble/misfire on it's way to it's high idle.
It will idle at 1k rpms, until it warms up. The engine will occasionally try to idle down, but then it starts to stumble over itself, and goes back up to 1k.

If I start driving when it's cold, I will push in the clutch, and the RPM's will hold at what they were, or even go up slightly, then slowly start going back down to 1k.

I did clean the TB/IAC after this all started, but nothing changed.
Plugs are perfect.
Have run a couple tanks through it, with different octanes, from different stations.



I also have a related/unrelated? ticking noise that comes and goes when cold.
The ticking will increase with RPM's, and seems to quiet down (not disappear) when the engine gets to running temperature.
I will cruise down the road at 1500 rpms and the ticking will vary in loudness.
You can hear the ticking at idle in the cab with the radio off. You can hear the ticking at high RPM's with radio on, which is really annoying.
If I start the engine up cold, and the ticking is not there, it will show up if I rev it really high.
It has also been the other way around, where I start it cold, and it's ticking, and I'll rev it up really high, and the ticking will go away.
It has the correct/right amount oil, and I have run Rislone and ATF through it. Clean Mopar filter too.
I have also checked exhaust bolts.

I have taken a automotive stethescope to the engine and could not locate the ticking. Sounds like valvetrain though.

Could the idle problem be caused by a bad TPS or IAC? Maybe CKP?

....

btw- this is not normal for a Jeep, if that's all you have to say.
What the hell do you do for a living to be working 15+ hours

First thing ..

The crap idle and revs holding up does sound like IAC.

Secondly ..

The ticking does sound like tappet noise .. and this one is normal for a Jeep

----------------------
Formally 88Jeepster
----------------------

Who's in front ?

Ridin' topless again .. sweet !!
Wif is offline  
post #6 of 12 Old 11-12-2008, 12:09 PM Thread Starter
peeweeXJ
Registered User
2002 TJ Wrangler 
 
Join Date: Nov 2004
Location: Gillette, WY
Posts: 1,281
Quote:
Originally Posted by Wif View Post
What the hell do you do for a living to be working 15+ hours

First thing ..

The crap idle and revs holding up does sound like IAC.

Secondly ..

The ticking does sound like tappet noise .. and this one is normal for a Jeep
I work at a mine, and I have a 13hr. shift + 3 hrs. on a coach bus to get there.

A tappet noise is consistent, it is not like a wristpin where it quiets down as it heats up.
It might be normal noise if people didn't look at me when I started it up.

Thanks


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
peeweeXJ is offline  
post #7 of 12 Old 11-12-2008, 12:24 PM
Wif
Registered User
 
Wif's Avatar
2004 TJ Wrangler 
 
Join Date: Nov 2004
Location: Just north of Calgary, Alberta, Canada
Posts: 2,990
Quote:
Originally Posted by peeweeXJ View Post
I work at a mine, and I have a 13hr. shift + 3 hrs. on a coach bus to get there.

A tappet noise is consistent, it is not like a wristpin where it quiets down as it heats up.
It might be normal noise if people didn't look at me when I started it up.

Thanks
Hydraulic tappets do this .. they can tap when cold due to oil starvation or incorrect viscosity oil, or tap when hot due to low oil pressure or incorrect viscosity oil.

Sometime noisy tappets can be caused by a faulty oil filter .. the anti-drainback valve letting all the oil from the oilways drain back into the sump.

----------------------
Formally 88Jeepster
----------------------

Who's in front ?

Ridin' topless again .. sweet !!
Wif is offline  
post #8 of 12 Old 11-12-2008, 12:44 PM Thread Starter
peeweeXJ
Registered User
2002 TJ Wrangler 
 
Join Date: Nov 2004
Location: Gillette, WY
Posts: 1,281
Quote:
Originally Posted by Wif View Post
Hydraulic tappets do this .. they can tap when cold due to oil starvation or incorrect viscosity oil, or tap when hot due to low oil pressure or incorrect viscosity oil.

Sometime noisy tappets can be caused by a faulty oil filter .. the anti-drainback valve letting all the oil from the oilways drain back into the sump.
That doesn't sound like a normal condition to me? Key words like low, starvation, incorrect, faulty.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
peeweeXJ is offline  
post #9 of 12 Old 11-12-2008, 01:09 PM
Wif
Registered User
 
Wif's Avatar
2004 TJ Wrangler 
 
Join Date: Nov 2004
Location: Just north of Calgary, Alberta, Canada
Posts: 2,990
Quote:
Originally Posted by peeweeXJ View Post
That doesn't sound like a normal condition to me? Key words like low, starvation, incorrect, faulty.

Normal doesn't mean correct .. most of the 4.0's do it. I was giving you examples of what can exaggerate the problem.

I'll wait for someone else to jump in here ..

----------------------
Formally 88Jeepster
----------------------

Who's in front ?

Ridin' topless again .. sweet !!
Wif is offline  
post #10 of 12 Old 11-12-2008, 01:16 PM
grinwa
Registered User
 
grinwa's Avatar
1999 TJ Wrangler 
 
Join Date: Mar 2005
Location: Port Orchard, WA
Posts: 478
Is it possible you have an exhaust leak? Check for one. If it get louder under a load and less when coasting, it could be an exhaust leak. That could cause problems with the O2 sensor, too.

'99 TJ

Experience is something you don't get until just after you need it.
grinwa is offline  
post #11 of 12 Old 11-12-2008, 01:35 PM Thread Starter
peeweeXJ
Registered User
2002 TJ Wrangler 
 
Join Date: Nov 2004
Location: Gillette, WY
Posts: 1,281
I have thought about an exhaust leak, but I checked as good as I could visually, and tried to tighten all the bolts that I could. They were all good n' tight. I'll go check again.

BTW- I ran it with the IAC unplugged and it made no difference. Still idled high, and tried to come down but stumbles.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
peeweeXJ is offline  
post #12 of 12 Old 11-12-2008, 02:25 PM Thread Starter
peeweeXJ
Registered User
2002 TJ Wrangler 
 
Join Date: Nov 2004
Location: Gillette, WY
Posts: 1,281
Haha, well I believe to have found my ticking problem. Had my stethescope out and was scoping around the engine. Could not tell where the ticking was coming from. Put my hand on the EVAP purge solenoid, and hole e crap does it ever tick. Could it actually be the really loud thing I hear when I start it up on cold mornings (4-6 LOUD ticks)?

Anyhow- Still not sure on the high idle/slight stumble. Seems like a rough spot, not exactly stumbling.

Thanks


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
peeweeXJ is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Low Idle Cold, High Idle Warm Lon33 YJ Wrangler Technical Forum 13 10-29-2014 10:24 PM
Rough Idle when cold firefighter1 TJ Wrangler Technical Forum 1 04-22-2013 09:25 PM
Rough Idle when Cold Titleistprov21 TJ Wrangler Technical Forum 3 11-05-2009 11:54 AM
Rough Idle on Cold Start rugbynut YJ Wrangler Technical Forum 15 03-13-2008 01:37 PM
Rough cold idle ckcarr TJ Wrangler Technical Forum 1 11-10-2004 04:45 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome