Help!!

Ok, so here is my problem......
I put my jeep through a water hole, that was a little bit deeper than I thought. My fault, I know I should have checked before hand. Anyways, I sucked up a little bit of water once I hit the hole, and it shut off immediately. It was deep enough to put the exhaust system in the water, and flood the interior. After getting pulled out, it still didn't want to start right away but eventually did but was not happy. Of course it was running like crap after. So after an oil change, and a new TPS (that was the only code) it started up and idled fine, for a minute. I drove it around the block and it started adding up again. It started sputtering and losing power. So then I replaced the cap, rotor, wires, and plugs again it started fine. But then again it started running like crap and the "check engine" light came on again. This time it came back as the TPS again, bank 1 running too lean, and circuit too slow:smsoap: . Here is what it is doing.....
It starts fine, and idle is ok, but after it warms up at 2000 rpm it sputters and bogs down until 3000 rpm, and then it picks up power again. I will occasionally see some black smoke come out, and can smell the exhaust pretty well. Does anyone have any suggestions?!?!?:helpme: .
The vehicle is a '99 Jeep Cherokee Sport auto w/ 4.0.
Someone please help!!!!

Pull out your ECU and See how much water is on your connectors. The Old school rigs faired a little better when it came to water because they did not have 2000 feet of wiring to posibly short. check there and go through as many connectors that you suspect got wet. it is a start and something you need to look into but may not be the fix.

Did you pull the plugs before you started it the first time?
Did you use any engine cleaner at one of the oil changes?
Could it be that you have an internal problems outside of the area of electronics?

Good call on the TCU!!!

sprngfldxj said:

Did you pull the plugs before you started it the first time?
Did you use any engine cleaner at one of the oil changes?
Could it be that you have an internal problems outside of the area of electronics?

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I am going to have to go with no on all of the above. This is my first of 3 jeeps I have owned that I have actually wrenched on myself, so I am still learning a lot. What advantage or purpose does pulling the plugs before the first start?
I will definitely check the connectors on the ECU. I am off sunday, and am planning on working on her all day so any advice or tips would help. A couple of people I have talked to said I may have an ignition problem, does this sound possible?

sprngfldxj said:

Did you pull the plugs before you started it the first time?
Did you use any engine cleaner at one of the oil changes?
Could it be that you have an internal problems outside of the area of electronics?

Click to expand...

Yeah. My experience with taking my XJ swimming ended up with me having to drop the tank and clean out all the fuel lines/new filter/pump since its a 97 in addition to plugs, etc...

BUt your problem doesn't sound like a clogged fuel line or contaminated fuel to me.


All I know is that even with engine cleaner, oil changes, new plugs, clean fuel tank and lines I still pulled out a plug that was fouled with sand 20k miles later. I pulled that plug out 20k ago. No sand anymore but I just turned 108k on an engine that was hydrolocked by water running in the fill neck almost 40k miles ago.

I'm not too good with electronics so I'm sorry I can't offer better advice than to make sure that no sediment or water remains in your fuel path, and that should be done whether it turns out to be the ECU or not. It doesn't sound to me like something as simple as a fuel issue, so good luck in getting it back running and again, sorry I can't be of more help.

No more ponds! or tie swimmies to that sucker!!! Good luck, I hate computer issues. Damn all those sensors... and no mater which sensor is bad it always says TPS (one of the most expensive of course) It's a long shot but maybe your O2 sensors? They def went swimming. and I've seen O2 sensors do some crazy shit before. Test those. Hope it runs!

lowrange2 said:

No more ponds! or tie swimmies to that sucker!!! Good luck, I hate computer issues. Damn all those sensors... and no mater which sensor is bad it always says TPS (one of the most expensive of course) It's a long shot but maybe your O2 sensors? They def went swimming. and I've seen O2 sensors do some crazy shit before. Test those. Hope it runs!

Click to expand...

That is exactly what I was thinking. On the throttle body, there are 2 sensors. I am not sure if it was the right one I replaced. When I went to the auto parts store, I just asked for a TPS sensor and they gave me one, but after looking I started to question it. So my question is...are there 2 TPS sensors? Also, what are some ways I can test the o2 sensors? Because I will agree that they definitely had a nice little dip, because from what I was told a good amount of water came out of the exhaust when it started up. Thanks for the help.

Lowrange2 is on the right track. If your jeep was deep enough that water got inside the cab, then your O2 sensors definitely took a bath.

Lean on Bank 1 and Slow response are both Oxygen sensor codes.

Replace your O2 sensors and you should be good.

The reason it runs good until you get it warmed up is the ECU is metering the fuel when the system is cold, and when the oxygen sensors get heated up to 600* then they start metering the fuel. Well if they have been damaged due to water, dirt, debris, etc.. then they will be throwing off false readings, causing the ECU to dump fuel when it doesn't need to.

Replace your O2 sensors and report back.

There are methods to test your O2 sensors to see what voltage they are outputting at normal operating temp. Grab your Haynes/Chiltons/FSM and start testing per their procedures.

Hope this helps.

Glad to have been of decent help... She running yet?

Ok, so I haven't been able to reply back recently due to work. Anyways, she is still running poorly. hasta I am heading out early tomorrow morning to oakland, and when i get back I plan on swapping out the o2 sensors. Where is the least expensive place to get them? Also, I don't believe I mentioned this but I was getting 4.5 mpg. I don't know if that might give a little more insight to what is going on. AND, the other day I was driving it around the block and the "check engine" light started flashing on me! But my Jeep felt like it was running a little bit better afterwards?!?!? :huh: Well, I will let you all know what is going on when I get back. Thanks for everyones insight.:wave:

Ok well, it looks to be fixed. Put in 2 new o2 sensors and noticed an immediate difference. The "check engine" light was still on after everything got hooked back up. The next morning it was still on for the commute to work, but it ran great and netted 15 mpg's! After work I went to get some food, and when I got done and was leaving the "check engine" light didn't come on and has not come back on. So I'm keeping my fingers crossed, but everything is looking good. I am back to the normal 12-14 mpg's and driveability is A LOT better. arty: Anyways, thanks VERY much for everyones input it was greatly appreciated. I definitely think I will greatly benefit from a complete exhaust upgrade from the stock system that's on there right now, because I'm sure the cat and muffler didn't enjoy the swim and post stress. Here are a couple pics I finally am getting around to posting for you guys...
Here was the incident that caused all the problems!


Here are the old o2 sensors. There was a pretty good coat on there. Also, I'm pretty sure they were never changed out until now with over 96k.