Rubicon Owners Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
454 Posts
Discussion Starter #1
Does/did anyone notice a power lag in the first few gears? I have been driving mine around lately and have been noticing that as soon as you shift into the first 3 gears there seems to be a lag in the power. The torque just doesn't seem to be there and then the engine just wakes up. I have talked to a few other people with '03 Rubicons and they have had the same experience. Anyone have any ideas?
 

·
Premium Member
Joined
·
3,745 Posts
triver525 said:
Does/did anyone notice a power lag in the first few gears? ...... I have talked to a few other people with '03 Rubicons and they have had the same experience. Anyone have any ideas?
It's probably the fuel sync out of range. It's been discussed on JU on this thread http://jeepsunlimited.com/forums/showthread.php?s=&threadid=363169 and this threadhttp://www.jeepsunlimited.com/forums/showthread.php?s=&threadid=345247&perpage=20&pagenumber=4 5 speeds seem to be more susceptible to it than the automatics.

HTH.

Jerry
 

·
Registered
Joined
·
135 Posts
This hesitation problem is well documented. I had mine fixed at the dealer. They had to ajust the cam sensor. See the above links. It feels fine now..
 

·
Registered
Joined
·
454 Posts
Discussion Starter #4
I went and had mine fixed and I still feel it. I am going to have to take it in again.
 

·
Registered
Joined
·
1,530 Posts
I have the hesitation once and a while but once I put on a K&N I have not noticed it as much if not at all...
 
G

·
Guest
Joined
·
0 Posts
The dealer told me my muffler bearing needed to be replaced :wink: . No, really, they said my cam sensor setting was dead on but that there was some emergency kill switch that was shorting out.
 

·
Registered
Joined
·
1,530 Posts
Can you get more info on the switch that they are talking about?.. I am taking the JP in for service soon and would like some good research on the problem and what has worked to fix it.

Cheers

Sean
 
G

·
Guest
Joined
·
0 Posts
LILRDJP said:
Can you get more info on the switch that they are talking about?.. I am taking the JP in for service soon and would like some good research on the problem and what has worked to fix it.

Cheers

Sean
I'm not exactly sure what its called but its an emergency kill switch that kills the power in the event of an accident. They said that since it was shorting out it could possibly have been intermittently trying to kill the power. But that sounds like an anomoly. What you really want to have them look at is the settings for the cam sensor above the oil pump.
 

·
Registered
Joined
·
1,530 Posts
RubiRedJeep said:
LILRDJP said:
Can you get more info on the switch that they are talking about?.. I am taking the JP in for service soon and would like some good research on the problem and what has worked to fix it.

Cheers

Sean
I'm not exactly sure what its called but its an emergency kill switch that kills the power in the event of an accident. They said that since it was shorting out it could possibly have been intermittently trying to kill the power. But that sounds like an anomoly. What you really want to have them look at is the settings for the cam sensor above the oil pump.
I am going to get the sensor checked. I was just looking for extra ideas incase it is not the problem....Thanks for the info I will check with dealership.

Cheers
 
G

·
Guest
Joined
·
0 Posts
Good luck with the dealer. My local dealer doesn't seem to have a clue about them.
 
G

·
Guest
Joined
·
0 Posts
Hesitation

I've been noticing a slight hesitation from 1-2 and 2-3 (right after shifting). I tried different shifting (clutch and acceleration) methods to see if it affected it. Didn't know if speed vs. slow shifting made any difference. Not really.

This hesitation has no pattern/or is unpredictable. I've been running K&N filter for about 2 weeks now. Yet, I just started noticing this hesitation earlier this week.

Might take it to the dealer here shortly, w/o the K&N, if that makes a difference (don't know this dealer too well yet).
 
G

·
Guest
Joined
·
0 Posts
I've noticed the power lag when shifting from 1-2 and 2-3. My rubi is an 03 with about 7000 miles on it. The power lag started at about 5000 miles or that's when I noticed it. I do my own maintenance but for the next one I'll bring it to the dealer to have 'em check it out.
 

·
Registered
Joined
·
184 Posts
Once again I am not alone. Mine has had major lag like going up hill all the time, brakes dragging but calipers still cold? Gas milage no good. As far as the clutch, I don't ride it. I like to get it enguaged at the lowest rpm then mash the gas. A lot of times I will get off the clutch idleing then step on it. Hate to down shift, only do it when other cars are zig-zaging behind me and my tach is dragging.

Must learn more about this bored out throttle body and resetting the sync to 0 and how it will effect Kalifornia smod laws 8)
 
G

·
Guest
Joined
·
0 Posts
My wife owns an 03 Rubicon (w|auto 4speed trans.) with about 6000 miles and have not experienced said hesitation but have noticed that at times, (after short 15 minute cooling period then restarting and accelerating at W.O.T. or close to it) a slight noticeable increase in accelleration performance. I attribute this to the ECM \ Engine starting off in OPEN LOOP (which is RICHER in nature) for the first few 10 to 20 seconds. This makes sense, concerning the Jeep 4.0 speed density fuel injection system (non mass air flow sensor equipped) and their less than ideal fuel metering, I believe,....IF the cam\fuel sync sensor is properly adjusted, then what everyone is probably experiencing is a stingy lean ECM program and will be more noticeable in cooler moist\weather. The only cure is an ECM re--calibration,.....period. I've been fighting this exact same problem on my 69 Chevy 1\2 ton stepside 4X4 with Ramjet 350 fuel injected crate motor for 2yrs. now, and have just found the cure by installing an updated ECM with a different program. Altough the Jeep hesitating problem is no where as severe as my Ramjet, It runs so much better now,... I dont know how to act
As for the Jeep 4.0, the only place I'd trust to Re-program the ECM is Kenne Bell. You all owe it to yourselves to read and learn this:
http://www.kennebell.net/techinfo/dodge ... 40tech.pdf
Also keep in mind,... that although this info was learned from their supercharger testing, (again, the only one I'd use), that they still recommend the re-program for non supercharged Jeeps due to the excessively lean stock fuel curve. THANKS, Tommy
 
1 - 14 of 14 Posts
Top