big problem in my KJ

[cherokee4ever]

hello guys
from 2 year i got my jeep into a deep water and when i get out of the water the engine light came on with shaking.
the next day i take the car to work shop and they replaced the O2 sensor and it work fine but after 5 month the light came on.
and i check every thing but until now not fixed, and this what i do to fix this problem:

* i cleaned the fuel Injectors and it didn't work .
* removed the all Catalytic converter and it helped a bit but the light still on.
* cleaning the fuel filter and so i didn't help.
* i chenged the air filter and oil filter and the sparks and still the same.


by the way i have the airbag light came on and i didn't have any Accident till now.

any suggestion for fixing my Problems

 

[jnaut]

Try to get a code. Turn key to the on position three times (without starting the vehicle).

Key ON
Key OFF
Key ON
Key OFF
Key ON

Engine will display last code thrown by the computer. If it's not throwing a code it will just say "Done."

Try to get that code and post it here.

 

[cherokee4ever]

i get this codes :
122
420
432

 

[jnaut]

ON the O2 sensors, remember, your jeep has four of them. So if you replaced one, you could have any one of the three others failing.

 

[wheeee32]

ON the O2 sensors, remember, your jeep has four of them. So if you replaced one, you could have any one of the three others failing.

We've got 4 O2 sensors?! Dang.

 

[ThunderbirdJunkie]

For the most part...The only time O2 sensors fail is when there's another problem...

Check the wiring and plugs to said O2 sensors. And change the throttle position sensor.

 

[tjkj2002]

If your the infamous sank KJ(from pics on the web) you'd better be looking at new cats.

 

[ohaness]

yes...2 upstream of the Cat (left and right side), and two downstream (left and right)...total of 4

 

[jnaut]

For the most part...The only time O2 sensors fail is when there's another problem...

Check the wiring and plugs to said O2 sensors. And change the throttle position sensor.

O2 sensors do have a limited life (I'll let someone else chime in on what that life is) and can be damaged by extensive use of fuel additives and the like.

 

[cherokee4ever]

thank you all for your respone
but for O2 sensor i replace 2 of them but i have removed the Catalytic converter is this effect on O2 sensors

 

[tjkj2002]

thank you all for your respone
but for O2 sensor i replace 2 of them but i have removed the Catalytic converter is this effect on O2 sensors

Yes,you need those cats so your PCM via the O2 sensors(among other sensors) can set the correct fuel/air ratio and timing for the engine to run correctly.

 

[kb0nly]

Ahhh... He REMOVED the CAT. Now it all makes sense, the error codes and erratic idle, etc.

Do yourself and the world a favor, put it back on!

 

[Atrus]

Removing the downstream O2 sensors shouldn't cause any driveability issues, should it? I can't comment specifically on the KJ, but in my past experience those are only for emissions and trigger an CEL to get the operator to get the cat/sensor checked out. From what I have seen those downstream O2's are purely used to trigger the CEL light and identify a potential issue with the cat(s).

The upstream O2's monitor fuel mixture and keep from an overly rich/lean condition.

Cliff's notes is that cutting off the cats, while illegal in the US and harmful to the environment, shouldn't make it run badly in my opinion.


I'd look to that TPS for it running badly first.

 

[cherokee4ever]

i can't put them back on i must buy a new Catalytic converter because my old one was in bad shape and plugged but i will try to fix Throttle Position Sensor.
and for the Environment one more car will not make a Different

 

[tjkj2002]

Removing the downstream O2 sensors shouldn't cause any driveability issues, should it? I can't comment specifically on the KJ, but in my past experience those are only for emissions and trigger an CEL to get the operator to get the cat/sensor checked out. From what I have seen those downstream O2's are purely used to trigger the CEL light and identify a potential issue with the cat(s).

The upstream O2's monitor fuel mixture and keep from an overly rich/lean condition.

Cliff's notes is that cutting off the cats, while illegal in the US and harmful to the environment, shouldn't make it run badly in my opinion.


I'd look to that TPS for it running badly first.

The downstream O2 sensors monitor cat efficiency and also help adjust the fuel/air mixture depending on the differences in voltage compared to the upstream O2's.

can't put them back on i must buy a new Catalytic converter because my old one was in bad shape and plugged but i will try to fix Throttle Position Sensor.
and for the Environment one more car will not make a Different

Your KJ will never run right without them,it's not so much for emissions either.Your PCM is programed for them so not having them will screw up your engine in very short order.Check out Summit racing,if you have a '02-'03 KJ with the 45RFE trans they sell all 3 direct fit(with pipes) cats for about $700 or so total.

 

[kb0nly]

I went through this same problem on the Pontiac Montana we had, i though "what's a CAT good for other than the environment" and i removed it when it got plugged and put a piece of pipe in its place. Of course i got the CEL for the downstream 02 sensor reading the same as the upstream and figured that was it and i could live with it, but then i started having driveability issues.

tjkj is correct, and what i said also is correct, it won't run right without it! The computer sees the signals are the same from both pairs of 02 sensors, or in your case if you have the downstreams removed and unplugged the same problem.

It's the comparison between the upstream and downstream sensors that tells the computer what it needs to do for fuel efficiency and to keep the engine running correctly.

 

[Atrus]

The KJ BCM/PCM is much more advanced than what I have experience with...

But on the GM L36 and L67's, it's common practice to yank the cat and run an "O2 sim". I put on a high flow cat, so I threw on the O2 sim to avoid a SES light. Ran it that was for a good 80k hard miles with no ill effects. This was on a '99.

 

[kb0nly]

The KJ BCM/PCM is much more advanced than what I have experience with...

But on the GM L36 and L67's, it's common practice to yank the cat and run an "O2 sim". I put on a high flow cat, so I threw on the O2 sim to avoid a SES light. Ran it that was for a good 80k hard miles with no ill effects. This was on a '99.

I did that on a 95 Neon, put one of those little black boxes in place of the downstream sensor and pulled the CAT, also pulled off the stock manifold and put on an aftermarket for better flow. Got an increase in gas mileage from it and it ran great.... Until all the electrical problems finally made me sick of owning it.

 

[cherokee4ever]

wow guys you made me scared of geting those problems, and i am now Complete 2 month from i removed the converters and the engine and driveability is too good Except the smell -not too bad but better then before- and i was getting engine heat problems and now it helped a bit.
but too much guys and Experts says this is good for the Engine because it will reduse the Pressure on the Engine and it make the air goes out from the Engine easly also the Catalytic converters it makes the Engine more hot.
and there is saying : what it is good for the Environment do not mean it is good for the Engine.