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Cherokeekid88
February 27th, 2012, 06:21
I noticed on Saturday, I drove about 20 miles and everything was fine. drove across the street and still was all fine. Left that place to head back home...as soon as I got out of the parking lot to get on the road. I was pushing the gas down and it hesitated to the point where it wasn't going any faster. Like I was stepping on the gas but it wasn't going anywhere. it did it that one time for like 1 second and then went back to normal...drove the next 18-20 miles with no problem whatsoever. No slipping when shifting gears, pulled fine. Then I didn't drive it at all yesterday. This morning, I get in to go to work. I pulled out of my neighborhood and take a left and as soon as I straightened out, it did it again for a split second. The rest of the way to work (which is less than a mile) it was fine....The tranny shifts fine, so hesitation, so slipping, still feels strong. I haven't checked the tranny fluid yet...(am going to try and check it tonight after work, if its not raining too hard)

But it just has me puzzled. It doesn't really feel like a tranny problem, but then again, I am not so sure.

Any suggestions?

EDIT: Also, I have noticed that when I start my jeep up in the morning, it starts up normal and fine but after about 2 seconds it will get a buh buh buh buh sound from the exhaust almost like its not running right. I will hit the gas a couple times and it smoothes out and its fine and runs normal. could this be a sign of the fuel pump possibly going? I know I need to listen to see if I can hear it prime when I cut the jeep on, but I also have heard that they make a whining noise when they go bad.

Ecomike
February 27th, 2012, 10:08
Year?
if it is 88, whining noise for fuel pump is normal.

if 88, it sounds like early signs of a dying TPS sensor on the throttle body.

Cherokeekid88
February 27th, 2012, 12:20
Year?
if it is 88, whining noise for fuel pump is normal.

if 88, it sounds like early signs of a dying TPS sensor on the throttle body.

Sorry, its a 97.

Ecomike
February 27th, 2012, 12:49
Then get an OBD-II code and pending code scan, write down the numbers and post them here. If no codes, the TPS is the usual suspect if all the tune up stuff is good, and there are no vacuum leaks. O2 sensor is next on the list.

Cherokeekid88
February 27th, 2012, 13:03
Then get an OBD-II code and pending code scan, write down the numbers and post them here. If no codes, the TPS is the usual suspect if all the tune up stuff is good, and there are no vacuum leaks. O2 sensor is next on the list.

Well the TPS is not that old....Ill remove it tonight and clean it.

Also, I just thought of something. Anyone have have a little bit of gas in your tank and take a sharp turn and your car kinda of stalls until the gas is pushed back over to the other side?

That is exactly what its like when it happens.

Ecomike
February 27th, 2012, 13:07
OMG, DO NOT Clean the TPS. :tears: :rattle:

Do that and it is like putting water on a mugwamp, they turn into Gremlins!!!! LOL:D

Try keeping more gas in the tank!!!

Cherokeekid88
February 27th, 2012, 13:24
I always have gas in the tank, but the effect from that is similar to what I am experiencing but with a full tank of gas.

Cherokeekid88
February 27th, 2012, 14:29
well started my jeep up to go home and the CEL came on....checked the code....O2 sensor.....makes sense

there is an upstream and downstream 02 sensor on these things right?

I just had my exhaust redone about 2 weeks ago where they did mess with the cat and the 02 sensor on the cat is probably maybe 2 years old......

Ecomike
February 27th, 2012, 18:16
It is not unusual for the wiring to the O2 sensor to not get re clamped and tied back up out of the way after yahoos :eek: work on it, LOL. This frequently results in the harness getting to close to the drive shaft and or road debris or the exhaust pipes ripping up the wires or burning them, resulting in a short and lost signal, and so on!!!

Sounds like door number, the O2 sensor is the winner this time. Turning a sharp corner may have allowed it to make contact and short the wires.

Cherokeekid88
February 28th, 2012, 05:44
Had the codes read at Napa. says BOTH sensors are throwing a code....There is a Firestone right up the street from where I work and I called there last night and talked to the guy and he knew who I was and what I drove and told me from jeep guy to jeep guy to come up there on wednesday and he will hook me up....

gradon
February 28th, 2012, 17:20
could be a blown mini-fuse underhood@pdc that provides the o2 heater elements 12v. Why it blew: look real good at the wiring by the cat(this issue didn't pop up until after the exhaust work, right?).

Cherokeekid88
February 29th, 2012, 06:24
could be a blown mini-fuse underhood@pdc that provides the o2 heater elements 12v. Why it blew: look real good at the wiring by the cat(this issue didn't pop up until after the exhaust work, right?).

Correct. guy at Firestone said he will look at it and probably go ahead and replace the the upstream 02 ( it hasn't ever been changed as far as I know) and check the wiring on the downstream 02.

Cherokeekid88
February 29th, 2012, 07:37
Ok, so guy called and said that the problem is, when I had my exhaust redone last, they put the 02 sensor (upstream) to far away and it throwing the code and that the 02 sensors themselves are fine. But if the 02 sensors are fine, but still throwing a code would it cause my jeep to feel sluggish still?

So now I am going to gave to take it somewhere and get them to move the upstream o2 sensor closer i guess.... I really don't understand how they could mount it any further away than it was before....

Cherokeekid88
February 29th, 2012, 08:30
turns out its a depth issue with the upstream 02 sensor....

Shorty
February 29th, 2012, 08:54
Ok, so guy called and said that the problem is, when I had my exhaust redone last, they put the 02 sensor (upstream) to far away and it throwing the code and that the 02 sensors themselves are fine. But if the 02 sensors are fine, but still throwing a code would it cause my jeep to feel sluggish still?

So now I am going to gave to take it somewhere and get them to move the upstream o2 sensor closer i guess.... I really don't understand how they could mount it any further away than it was before....

The O2 sensor is mounted close to the manifold to keep it hot enough to function (600+ degrees)

The XJ has a heater circuit built into it to aid in the heating at start-up.

Without any exhaust leaks, the content of the exhaust shouldn't be significantly different anywhere between the manifold and the catalytic converter.

I'd inspect the heater circuit for faults before I paid to move the sensor closer to the manifold-- as stated, there is a fuse in the PDC that often blows and results in heater circuit malfunction.

xjbubba
February 29th, 2012, 09:12
I'd suspect the wiring harness would not allow the O2 sensor to be moved excessively, and as stated previously, the O2 has a heater to maintain op temp.
Spend your time looking for wiring problem.

Ecomike
February 29th, 2012, 09:55
The O2 sensor is mounted close to the manifold to keep it hot enough to function (600+ degrees)

The XJ has a heater circuit built into it to aid in the heating at start-up.

Without any exhaust leaks, the content of the exhaust shouldn't be significantly different anywhere between the manifold and the catalytic converter.

I'd inspect the heater circuit for faults before I paid to move the sensor closer to the manifold-- as stated, there is a fuse in the PDC that often blows and results in heater circuit malfunction.

He has a 97. Did the 97 still have an electric heater in the O2 sensor, or was it the year the pre Cats replaced the electric heater?

Shorty
February 29th, 2012, 10:03
4 wire sensor has a heater-- I don't think it ever changed, even after the precat. exhaust was introduced. The '97 shouldn't have the precats, anywho IIRC.

Ecomike
February 29th, 2012, 10:06
Some one told me recently that 2000-01 had precats, and that they dropped the O2 electric heater. I learned recently that the pre cats (in general) supply the warm up and idle heat for the O2 sensors now, and ended the need for the electric heaters in the O2 sensors.

Shorty
February 29th, 2012, 10:13
I can't speak for the circuitry of the '00-'01 as I don't have one, but I know they still use the 4 wire O2 sensor and I'd be surprised if the heater was just floating in Limbo vs. being used.

Someone with a '00-'01 will have to chime in on the circuitry for the heater.

Cherokeekid88
February 29th, 2012, 10:14
according to the guy at Firestone, its not a matter of distance its a matter of depth. he is saying that the people did my exhaust last used a nut that is pretty thick and the 02 sensor is not far enough inside the pipe to get an accurate reading and that is whats throwing the code....I haven't seen the said nut yet, but will check it out this afternoon.

Anyway, The guy that I am taking it to tomorrow said he will fix it for $20...I will check out the fuse for the heater circuit as well this afternoon.

Ecomike
February 29th, 2012, 10:20
I can't speak for the circuitry of the '00-'01 as I don't have one, but I know they still use the 4 wire O2 sensor and I'd be surprised if the heater was just floating in Limbo vs. being used.

Someone with a '00-'01 will have to chime in on the circuitry for the heater.

It could be that it was the California emissions package only that changed the way I described. I do know it was a dual O2 sensor (2 wire IIRC), dual pre cat for California I was reading about and discussing recently, but I thought I had read about pre cats on earlier jeeps, as far back as 97, but I am not sure. Mine are all Renix.

Ecomike
February 29th, 2012, 10:23
I can't speak for the circuitry of the '00-'01 as I don't have one, but I know they still use the 4 wire O2 sensor and I'd be surprised if the heater was just floating in Limbo vs. being used.

Someone with a '00-'01 will have to chime in on the circuitry for the heater.


See the picture in post nine!

http://www.naxja.org/forum/showthread.php?t=1079789&page=2

"Originally Posted by Tim_MN http://www.naxja.org/forum/skorpyoimages/buttons/viewpost.gif (http://www.naxja.org/forum/showthread.php?p=245593005#post245593005)
Some 2000 XJ's were built with CA emissions, mini-cats and 4 O2 sensors, even ones that were not delivered to CA dealerships. All 2001 have CA emissions, mini-cats, and 4 O2 sensors."

They all look like 2 wire sensors!!!

And now I am wondering if the dual Pre cat proximity to the head, and special manifolds helped to kill the 0331 heads when the engine ran too rich!!!!!!!!??????

Shorty
February 29th, 2012, 10:26
2001 all had the same precat. emissions package and it looks like a 4 wire to me-- I don't think I've seen a 2 wire on any XJ (Cali. or Federal)

http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//291/full/19370009_bos_13100_pri_detl.jpg (http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//291/large/19370009_bos_13100_pri_larg.jpg)
Hover over the image to zoom in
http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//291/mini/19370009_bos_13100_pri_mini.jpg (http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Premium-Oxygen-Sensor-Bosch_19370009-P_291_R%7CGRPEMISAMS_____#)




Bosch Premium Oxygen Sensor




Oxygen Sensor OE Type - Upstream Front
Yes, this part fits your 2001 Jeep Cherokee. Change vehicle

Ecomike
February 29th, 2012, 10:38
2001 all had the same precat. emissions package and it looks like a 4 wire to me-- I don't think I've seen a 2 wire on any XJ (Cali. or Federal)

http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//291/full/19370009_bos_13100_pri_detl.jpg (http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//291/large/19370009_bos_13100_pri_larg.jpg)
Hover over the image to zoom in
http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//291/mini/19370009_bos_13100_pri_mini.jpg (http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Premium-Oxygen-Sensor-Bosch_19370009-P_291_R%7CGRPEMISAMS_____#)




Bosch Premium Oxygen Sensor




Oxygen Sensor OE Type - Upstream Front
Yes, this part fits your 2001 Jeep Cherokee. Change vehicle

Agreed, I checked AZ also, all seem to be 4 wire. So it seems Jeep stuck with the 4 wire system.

Cherokeekid88
March 1st, 2012, 06:53
Checked the fuse for the heater circuit...was bad...replaced it...feels better....but still took it to get the bung replaced to have the sensor further in the pipe. Guy said he fixed it and the light is gone and is no longer throwing codes....

Ecomike
March 1st, 2012, 10:43
Next question, why did the fuse blow?

Cherokeekid88
March 1st, 2012, 11:16
Just got the jeep back. The guy moved the o2 sensor about a 1/4 of an inch further in the pipe. Jeep feels good now, no CEL. Hopefully that did the trick.