96 jeep xj has no power!
06-28-2017, 06:14 PM
#1
Newbie
Thread Starter
Join Date: Jun 2016
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
96 jeep xj has no power!
Alright so this started occurring about half a year ago. I noticed it when I was going up a steep canyon and my jeep had no power and the pedal was to the metal. My jeep slowed all the way down to 35 mph before I got over the top. The next day it was fine for a week or two and then it happened again. Fast forward to the present and it's on and off. Sometimes when I floor it it'll have some ***** most the time it won't and accelerate very slowly. My first thought was a plugged cat so I took it off and nothing change. I straight piped into a cherry bomb but didn't weld it. Could the exhaust leaks cause this major performance loss? I know we can't talk about straight piping but I only did it to diagnose this problem. Any help would be greatly appreciated. P.s. I already adjusted the kickdown cable.
06-28-2017, 06:51 PM
#2
CF Veteran
Considering what you did to the exhaust with no change in behavior it is likely a fuel or air problem. If putting the pedal to the metal did not help, or change the behavior, then I would first suspect the fuel pump is falling behind under heavy load. This could also implicate a fuel filter that is not letting fuel travel fast enough.
If you had said that your engine came a live when you put the pedal to the metal, then I would be suspecting O2 and MAP sensors. Because those can mess up air/fuel mixture when they are failed or failing. But stomping on the pedal (wide open throttle = WOT), they are typically ignored and static values are used by the computer.
These are just possibilities based on what you have shared so far.
If you had said that your engine came a live when you put the pedal to the metal, then I would be suspecting O2 and MAP sensors. Because those can mess up air/fuel mixture when they are failed or failing. But stomping on the pedal (wide open throttle = WOT), they are typically ignored and static values are used by the computer.
These are just possibilities based on what you have shared so far.
06-28-2017, 06:56 PM
#3
Junior Member
Join Date: Jun 2016
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Hey man I appreciate your input! I will definitely change the fuel filter first since it is cheap. If that does not work I'll go on to the fuel pump. Does this explain the on/off power? Would it throw a code??
06-28-2017, 06:56 PM
#4
Junior Member
Join Date: Jun 2016
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Considering what you did to the exhaust with no change in behavior it is likely a fuel or air problem. If putting the pedal to the metal did not help, or change the behavior, then I would first suspect the fuel pump is falling behind under heavy load. This could also implicate a fuel filter that is not letting fuel travel fast enough.
If you had said that your engine came a live when you put the pedal to the metal, then I would be suspecting O2 and MAP sensors. Because those can mess up air/fuel mixture when they are failed or failing. But stomping on the pedal (wide open throttle = WOT), they are typically ignored and static values are used by the computer.
These are just possibilities based on what you have shared so far.
If you had said that your engine came a live when you put the pedal to the metal, then I would be suspecting O2 and MAP sensors. Because those can mess up air/fuel mixture when they are failed or failing. But stomping on the pedal (wide open throttle = WOT), they are typically ignored and static values are used by the computer.
These are just possibilities based on what you have shared so far.
06-28-2017, 07:01 PM
#5
CF Veteran
If it is intermittently beginning to fail, yes, it can come and go (fuel pump). on a 96 (same as mine), there is no specific sensor or monitor watching the fuel pump, and there is no code specifically related to it (for example, if voltage was low to the pump, there would be no specific code for that). However, if the pump is degraded in a consistent way, sometimes the computer will begin to throw "lean" condition codes, because it compensates for the lack of fuel by asking the injectors to inject more. When it has reached a high level of compensation (trying to make the mixture richer by adding more fuel), it will reach a maximum and throw the lean code (P0171). The problem is, this code can be caused by other things as well, so it is not fuel pump specific.
06-28-2017, 07:16 PM
#6
Junior Member
Join Date: Jun 2016
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
If it is intermittently beginning to fail, yes, it can come and go (fuel pump). on a 96 (same as mine), there is no specific sensor or monitor watching the fuel pump, and there is no code specifically related to it (for example, if voltage was low to the pump, there would be no specific code for that). However, if the pump is degraded in a consistent way, sometimes the computer will begin to throw "lean" condition codes, because it compensates for the lack of fuel by asking the injectors to inject more. When it has reached a high level of compensation (trying to make the mixture richer by adding more fuel), it will reach a maximum and throw the lean code (P0171). The problem is, this code can be caused by other things as well, so it is not fuel pump specific.
06-28-2017, 07:54 PM
#7
CF Veteran
Join Date: May 2012
Location: Lost in the wilds of Virginia
Posts: 7,964
Received 952 Likes
on
767 Posts
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
It's inside the tank, so it's a bit of a pain. You have to drop the tank. The J-bolts holding the straps are usually rusted pretty badly, and it's common to have to cut them off. Factory replacements are stupidly expensive, but there are alternatives. Just search her on J-bolts.
Trending Topics
06-28-2017, 08:28 PM
#8
Senior Member
Join Date: Mar 2014
Location: Eastern Long Island, NY
Posts: 952
Received 55 Likes
on
50 Posts
Year: 1996
Model: Cherokee
Engine: I6 Cyl / 4L
What Blueridgemark said.
It's no fun dropping the fuel tank. First try taking the fuel sending unit (which holds the fuel pump inside the tank) out without dropping the fuel tank. It should be on the front, vertical side of the fuel tank.
Make sure to drive around first and get the fuel tank as empty as possible, so that you don't take a gasoline shower when you open it.
There is a lock ring with a rubber oring that holds the sending unit in place. The lock ring has tabs that you can lightly punch with a brass punch (no spark) and turn the ring till it opens. Mine was stuck real good so I had to drop the tank. Anyway, make sure to get a new oring first. Patience is everything.
Don't forget to undo the filler hoses if you drop the tank.
Here is close up of the lock ring.
And the whole sending unit with pump.
Another pic of the unit on the tank.
It you take down the tank, look for rust spots on it. I found some on mine and just decided to clean it off and paint it. It will add some life to it.
It is handy to have a glass jar with a lid to collect the gas from the fuel filter. And a larger bucket for the remaining fuel in the tank if you decide to move it around and paint it, you are going to need to empty it. It goes without saying, smoking is bad.
It's no fun dropping the fuel tank. First try taking the fuel sending unit (which holds the fuel pump inside the tank) out without dropping the fuel tank. It should be on the front, vertical side of the fuel tank.
Make sure to drive around first and get the fuel tank as empty as possible, so that you don't take a gasoline shower when you open it.
There is a lock ring with a rubber oring that holds the sending unit in place. The lock ring has tabs that you can lightly punch with a brass punch (no spark) and turn the ring till it opens. Mine was stuck real good so I had to drop the tank. Anyway, make sure to get a new oring first. Patience is everything.
Don't forget to undo the filler hoses if you drop the tank.
Here is close up of the lock ring.
And the whole sending unit with pump.
Another pic of the unit on the tank.
It you take down the tank, look for rust spots on it. I found some on mine and just decided to clean it off and paint it. It will add some life to it.
It is handy to have a glass jar with a lid to collect the gas from the fuel filter. And a larger bucket for the remaining fuel in the tank if you decide to move it around and paint it, you are going to need to empty it. It goes without saying, smoking is bad.
06-29-2017, 10:53 AM
#11
Hook a fuel pressure gauge to the rail & find out....
I have hood vents so it made it easier to stick out the hood, hell take the hood off, hook the gauge to it & see if that is where you are falling flat.
Before I replaced my pump I was flooring it and it was bogging down....
06-29-2017, 06:41 PM
#13
CF Veteran
Does the problem only happen in 4th gear? Or is it that it gets progressively worse as the vehicle up-shifts and is most obvious in 4th gear?
06-29-2017, 06:55 PM
#14
Junior Member
Join Date: Jun 2016
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
yeah a little something like that! So floor going about 45-50 it's at about 2500 rpm and then once I hit 55 it shoots down to about 1800. But that is only sometimes but is happening more and more.
06-29-2017, 06:58 PM
#15
Junior Member
Join Date: Jun 2016
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Hook a fuel pressure gauge to the rail & find out....
I have hood vents so it made it easier to stick out the hood, hell take the hood off, hook the gauge to it & see if that is where you are falling flat.
Before I replaced my pump I was flooring it and it was bogging down....
I have hood vents so it made it easier to stick out the hood, hell take the hood off, hook the gauge to it & see if that is where you are falling flat.
Before I replaced my pump I was flooring it and it was bogging down....