Forum Index
Jeep Horizons HomeLinksJeep Horizons Tech Write-upsJeep newsLand useContact

 Watched TopicsWatched Topics   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Running Lean, one crisis at a time


 
Post new topic   Reply to topic     Forum Index -> General Tech
View previous topic :: View next topic  
Author Message
Faust
Member


Joined: 17 Sep 2007
Location: Missouri

PostPosted: Mon Sep 17, 2007 7:50 pm    Post subject: Running Lean, one crisis at a time Reply with quote

SYMPTOMS: Hard to start, glowing red exhaust manifold, decent idle, no power over 2,300 RPM (wavers up and down), gets to temp fast. Running very lean.

WHAT I'VE CHECKED: Injectors, TPS, new MAP sensor, engine timing

What should I do? Previous owner said it's gone through 2 exhaust manifolds in 2 years.

Background Information: 1994 Cherokee 4.0, Auto, 4x4. Motor rebuilt 20,000 miles ago (180,000 then, 208,000 now). Idles fantastic less an extremely fast warm up to temp (maybe slighly beyond).

Thanks for any help
Back to top
View user's profile Send private message
ThePhantum
Pissed-Off Admin
Pissed-Off Admin


Joined: 23 Jan 2004
Location: I knew it...I'm surrounded by Assholes!

PostPosted: Tue Sep 18, 2007 6:10 am    Post subject: Reply with quote

Might be a problem with the Cat...if it's clogged, it will cause both heat to back up into the manifold and a loss of power.
_________________

97 XJ Sport with a bunch of stuff
Quote:
Never argue with idiots, they drag you down to their level and beat you with experience
Back to top
View user's profile Send private message AIM Address Yahoo Messenger MSN Messenger
Faust
Member


Joined: 17 Sep 2007
Location: Missouri

PostPosted: Tue Sep 18, 2007 8:12 pm    Post subject: Reply with quote

I disconnected the exhaust behind the manifold and it ran as crappy as ever. This would rule out the O2 sensor or a clogged cat. I also put on a new fuel filter tonight.

Recap:
Running hot (glowing) and lean
Decent idle, wavering above 2300 rpm
New MAP, fuel filter
Cat is flowing, O2 sensor okay
The intake gasket isnt leaking, no apparent vacuum problems
Timing is correct by the chain and gear
Hard to start

I am running out of options.
Back to top
View user's profile Send private message
Teriod
Member


Joined: 19 Jun 2007
Location: California

PostPosted: Wed Sep 19, 2007 5:21 am    Post subject: Reply with quote

two more things to check;

1. spun balancer(would indicate correct timing when its not)
2. bad computer

if in fact you dont have a problem with the cat or tps,, have you checked codes???

this sure sound like a plugged cat or out of time
Back to top
View user's profile Send private message
Faust
Member


Joined: 17 Sep 2007
Location: Missouri

PostPosted: Wed Sep 19, 2007 7:38 am    Post subject: Reply with quote

I know, that's what it sounds like to me too.

I thought about the computer but am not sure. The cat is newer and since I ran it last night soley through the manifold this seems to rule out the cat. The timing has been checked twice and the thing runs too good to be totally out of time. I am still able to drive it (short distances) with fair low rpm power. My CEL is on for a code 51 lean condition.
Back to top
View user's profile Send private message
Faust
Member


Joined: 17 Sep 2007
Location: Missouri

PostPosted: Wed Sep 19, 2007 7:39 am    Post subject: Reply with quote

Could the TPS do this though? I'll just go pick up another one if it is even a possibility. They are not that expensive.
Back to top
View user's profile Send private message
Teriod
Member


Joined: 19 Jun 2007
Location: California

PostPosted: Wed Sep 19, 2007 9:47 am    Post subject: Reply with quote

Faust wrote:
I know, that's what it sounds like to me too.

I thought about the computer but am not sure. The cat is newer and since I ran it last night soley through the manifold this seems to rule out the cat. The timing has been checked twice and the thing runs too good to be totally out of time. I am still able to drive it (short distances) with fair low rpm power. My CEL is on for a code 51 lean condition.


the harmonic balancers are usually made in two pieces pressed together with a rubber ring, if you look at the front of the balancer you'll see this if that rubber looks bulged or broken in any way it could have spun, and even a little could put u a few degrees off and into a lean condition checking this with a timing light will not see this, also yea a tps sensor could be putting you in a lean condition along with the cps sensor

your cel code 51 says oxygen sensor lean, if this sensor is out if could force the computer into a lean condition

you have many variables to check out here is a link that could help
http://www.autozone.com/servlet/UiBroker

check all vacumn lines and the egr to begin with
Back to top
View user's profile Send private message
Faust
Member


Joined: 17 Sep 2007
Location: Missouri

PostPosted: Wed Sep 19, 2007 2:20 pm    Post subject: Reply with quote

Ok, used the Modis to check the TPS and it reads really good and graphs a real nice flowing line as I press the gas.

I checked vacuum with a can of carb cleaner and there is no audible weezing.

I am going to check a few other things since the scanner is available to me.
Back to top
View user's profile Send private message
Faust
Member


Joined: 17 Sep 2007
Location: Missouri

PostPosted: Sun Sep 23, 2007 10:47 am    Post subject: Reply with quote

Ok, the TPS was great and I had them check the fuel pressure too. How feasible is the idea of a spun harmonic balancer?
Back to top
View user's profile Send private message
kickeraiwa
Member


Joined: 25 Jun 2007
Location: Elmira, NY

PostPosted: Fri Sep 28, 2007 2:56 pm    Post subject: Reply with quote

does the 94 have the MPI with the selonoid on the inlet. If the selonoid is stuck open it would lean your mixture and cause exsesive heat.
Back to top
View user's profile Send private message
Faust
Member


Joined: 17 Sep 2007
Location: Missouri

PostPosted: Thu Oct 04, 2007 7:56 pm    Post subject: Reply with quote

Issue Resolved: the DAMN O2 sensor. Yes, yes, I know. I thought I'd bypassed it when I dropped the exhaust but I guess that wasnt quite it. So...a headache and $200 poorer (diagnostics and part/labor) I have a Jeep that really does have 190 HP.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic     Forum Index -> General Tech All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Visit links4jeeps.com for write-ups, forums and clubs




Jeep®, Wrangler, Cherokee, Liberty and Grand Cherokee are copyrighted and trademarked to Chrysler LLC.
jeephorizons.com is not in any way associated with or endorsed by the Chrysler LLC.
All other content is copyright Jeep Horizons 2004-2008.
Tech write-ups Links Discussion board Land use News Site Map Terms of Use

Powered by phpBB © 2001, 2005 phpBB Group