Still have check engine light after replacing O2 sensors

[DharmaDog]

Where is the O2 heater fuse located? Is it in the cab or under the hood?

 

[jneary]

its under the hood. i think its a 10 amp.i cant remember what years had them, but a lot of times when they short out it blows that fuse.

 

[DharmaDog]

I checked under the hood and if it is there it isn't marked. Also my Haynes and even my service manual don't list hardly any info on the fuses.

 

[jneary]

dd you actually remove them one at a time to see if any were blown?

 

[DharmaDog]

No. Not yet. It's too dark out and I don't have a garage. Will have to do it in the morning. I was just looking at the inside of the cover for the power distribution center. Some things are listed, but O2 heater fuse is not.

BTW, thanks for the help.

 

[DharmaDog]

OK, I checked all the fuses under the hood. I found one blown 15. I have no idea what that fuse is for, but it is now replaced. I haven't driven it yet, but I'm anxious to find out what effect this has. I still can't believe that I can't find any info about the fuses in the service manual. If I'm exhibiting great stupidity or temporary blindness in locating this info someone please smack me around and point me in the right direction.

 

[jneary]

even the factory service manuals casn be confusing when it comes to wiring diagrams. the blown fuse was probably the problem if the o2 wires wee shorted. erase the faults and drive it , and see what happens.

 

[DharmaDog]

Good news. The backfiring and hesitation seem to be gone. I've stopped and started the jeep maybe 4 times today and it didn't happen once. It has been exhibiting these symptoms every time it was started for the last few months, so this is definite progress. I have not cleared the codes yet, so the light is still on.

 

[jneary]

clear the codes and it shold be ok. the pcm monitors the o2 heater when first started and cool. that is why the check engine light comes on when first started. that is what gave me the clue that the light came on when started after the wires for the downstream were shorted.

 

[DharmaDog]

Cleared codes and all is well so far.

Thanks for the help. Now I need to track down the exhaust leak. I hope it isn't a cracked manifold.

 

[jneary]

probably the exhaust manifold. that's the weakest link

 

[kirby]

I'll have to check those same things. Mine has been doing it for quite some time now and I have changed all the things that dharmadog has changed. Hopefully mine is the same problem. Mine is a 98 also.

 

[1bolt]

I know this is a seriously dead thread, but I have to say I have this exact same problem on my 97 that I got for $850 bucks, I was using search for something completely unrelated, happened to see the title of this thread and browsed it just by chance and realized instantly that I had stumbled on the answer to my own problem. Funny thing is I searched for hours here looking for the same symptom and found nothing.

Same symptoms, only losses power and backfires after a start.
I have pulled the cat, replaced both o2's cut the wiring harness and spliced out what looked like a bad section of wire (probably what blew the fuse)... WTF did they rout the o2 wires an inch from the #1 header tube for anyway?... tomorrow I was going to pull the cat and replace it with a straight pipe, thinking clogged cat. Man if it wasn't midnight I would be looking for that fuse right now.

rules! :guitar: anyway this is a bizar problem and I was no where near looking for a blown fuse!

 

[8inch89XJ]

well hey i have an 89 xj 4.0 with an aw4 and when my tranny wouldnt down shift i found it to be the tps so i replaced it and i was wondering what the voltage specs should be coming out of it because i think it is not adjusted right it idles really low when in gear....and the renault efi system doesnt store codes so im not sure why it idles low any help?

 

[kennzz05]

well hey i have an 89 xj 4.0 with an aw4 and when my tranny wouldnt down shift i found it to be the tps so i replaced it and i was wondering what the voltage specs should be coming out of it because i think it is not adjusted right it idles really low when in gear....and the renault efi system doesnt store codes so im not sure why it idles low any help?[/quote

try reposting with the proper topic
]

 

[1bolt]

Found the fuse, and unlabeled 15 amp mini in the power distribution center (under hood). Solved the problem...