2000 TJ 4.0L Running Way to RICH - HELP! - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > General Technical Discussions > Engines & Drivetrain > 2000 TJ 4.0L Running Way to RICH - HELP!

ROCK BOTTOM prices on LIFT KITS at Rockridge4wd!! WANT TO Savvy FREE SHIPPING!Year End Clearance Sale! Save 20%

Reply
Unread 03-09-2007, 03:23 PM   #1
Goose346
Registered User
2010 JK Wrangler 
 
Join Date: Dec 2006
Location: N.E. Oakland County, Michigan
Posts: 270
2000 TJ 4.0L Running Way to RICH - HELP!

2000 TJ 4.0L/auto, 96K miles -

My Jeep is running way to rich - the engine light came on so I took it to Autozone so they could pull the code. They stated the #2 O2 sensor was bad - so I changed both.

I cleaned the plugs of all the soot and re-gapped them. There is acceleration hesitation around 1800 rpm while accelerating and the idle is choppy when sitting at idle. Black exhaust pours out the tailpipe (like a diesel engine) when I step on the gas.

Could the MAP sensor be shot? Where is this located? or . . .
Should I check the fuel pressure just in case the fuel pump is going bad?

I need help guys . . . what is your guess?

Goose346 is offline   Reply With Quote Quick reply to this message
Unread 03-10-2007, 08:35 PM   #2
Nonya
Web Wheeler
1998 TJ Wrangler 
 
Join Date: Feb 2007
Location: Nice
Posts: 1,653
1st check the fuel pressure,if its much higher than 50 psi it will cause the troubles you discribe.A big vacuum leak could cause similair troubles but it would idle terrible.If you have a vacuum gauge check the manifold vacuum.I would look closely for a broken vacuum line or cracked hose etc.The lower the vacuum the higher the MAP signal,that will make it run very rich.
Nonya is offline   Reply With Quote Quick reply to this message
Unread 03-13-2007, 07:51 PM   #3
oldmanscherokee
Registered User
1992 XJ Cherokee 
 
Join Date: Dec 2003
Location: , MA.
Posts: 421
vaccum leak would lean it out not richen it up. the number 2 sensor doesnt do anything but monitor the after cat emmisions to determine if the cat is working it does nothing for air fuel ratio. the #1 sensor does all of that it self. a faulty map sensor could cause that. as well as high fuel pressure, a leaking injector. black smoke is raw fuel through the exhaust. a bad coolant sensor could as well. not the one that feeds the gauge but the one that feeds the pcm signal.
__________________
full time tech for chevy, part time trail rider
95 Ford Lightning (sold), 09 Caddy CTS-V, 04 Buell Firebolt XB12R w/true flame paint, 00 harley XL chopped, 81 Trans Am, 85 K5 Jimmy 4 inch w/35s, 92 cherokee
10,000 original miles
4.5 inch RC lift
32 11.5 bfg muds
oldmanscherokee is offline   Reply With Quote Quick reply to this message
Unread 03-14-2007, 09:52 PM   #4
RockPaws
Registered User
 
Join Date: Jun 2003
Location: Pahrump, NV
Posts: 830
Also check for a stuck open injector. Getting that much fuel and black smoke, there would almost have to be one stuck. You could pull the fuel rail and injectors off as a unit. Charge the line but don't start the engine, see if one flows.
__________________
[FONT=Trebuchet MS]01' Jeep TJ (Jeep #5)
3.5 RE Custom SuperFlex, Raingler, Kilby, Currie, Banks, Borla, American Racing, Custom mods, Always more in the works.
[URL=http://www.redrock4x4.com][COLOR=Blue]www.redrock4x4.com Rocks![/COLOR][/URL]
[URL=www.needhim.org/][COLOR=Blue]Need Him?[/COLOR][/URL][/FONT]
RockPaws is offline   Reply With Quote Quick reply to this message
Unread 03-15-2007, 01:57 AM   #5
Nonya
Web Wheeler
1998 TJ Wrangler 
 
Join Date: Feb 2007
Location: Nice
Posts: 1,653
vac leak will cause a rich condition,because of the map sensor
Nonya is offline   Reply With Quote Quick reply to this message
Unread 03-20-2007, 08:43 PM   #6
tjstroker
Registered User
 
Join Date: Mar 2007
Location: Kentucky
Posts: 35
Quote:
Originally Posted by RAG48
2000 TJ 4.0L/auto, 96K miles -

My Jeep is running way to rich - the engine light came on so I took it to Autozone so they could pull the code. They stated the #2 O2 sensor was bad - so I changed both.

I cleaned the plugs of all the soot and re-gapped them. There is acceleration hesitation around 1800 rpm while accelerating and the idle is choppy when sitting at idle. Black exhaust pours out the tailpipe (like a diesel engine) when I step on the gas.

Could the MAP sensor be shot? Where is this located? or . . .
Should I check the fuel pressure just in case the fuel pump is going bad?

I need help guys . . . what is your guess?
I just changed my cat converter becasue of these symptoms. The cat was shot, which caused the o2 sensor to read wrong due to carbon, and that caused a max rich condition. The Error codes I received was a bad map and o2 sensor but a map replacement failed to fix. Once I changed the cat, cleaned the o2, it ran great ever since.

How many miles? Do you have gas on the ground under the tailpipe and a black exhaust tip? mine did...
tjstroker is offline   Reply With Quote Quick reply to this message
Unread 03-20-2007, 09:18 PM   #7
oldmanscherokee
Registered User
1992 XJ Cherokee 
 
Join Date: Dec 2003
Location: , MA.
Posts: 421
Quote:
Originally Posted by Nonya
vac leak will cause a rich condition,because of the map sensor

and the the upstream o2 will read its leaned out not rich as the map would indicate, thats why all these sensors are here to have more then one baseline for ocassions like that
__________________
full time tech for chevy, part time trail rider
95 Ford Lightning (sold), 09 Caddy CTS-V, 04 Buell Firebolt XB12R w/true flame paint, 00 harley XL chopped, 81 Trans Am, 85 K5 Jimmy 4 inch w/35s, 92 cherokee
10,000 original miles
4.5 inch RC lift
32 11.5 bfg muds
oldmanscherokee is offline   Reply With Quote Quick reply to this message
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.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

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.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.