2000 XJ 4.0
I swapped in a reman'd engine almost 500 miles ago. The break-in has been going well and I just changed the oil for the first time today. Right after I finished changing the oil, I started her up and my engine light came on. I pulled the codes and got 0132, 0135, and 0138... o2 sensor codes. On the way to get the codes read, the engine was idling really rough while it was still cold. It was sputtering as if it was gonna die, and dropped to around 300rpm. Once it warmed up, it seemed to be fine.
I had an issue when I started up the new engine for the first time with the fuel synchronization. But I found some good instructions and followed them to line up the cam pos. sens with the top dead center of the camshaft. (toothpick method).
After I had done the fuel synch., everything seemed fine. But now I'm worried I messed it up again. Maybe I nudged the sensor while replacing the oil? Anyways, I really don't want to have to take it to a shop, but it looks like I may have to because I need their computers to properly tune my engine. Is there anything else I should try before taking it to the shop?
It may just be a coincidence that the O2 sensor codes have come up, and they may not related to your engine swap.
Inspect the O2 sensor wires and connectors for damage. The wires can be mis-located and come in contact with hot exhaust parts, leading to a short circuit. Test or consider replacing the O2 sensor as part of your routine maintenance.
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Well I cleared the codes and they haven't come back yet... And the engine seems to be running pretty well. I think I splashed some oil onto the exhaust manifold or something, or it was just a fluke? If it comes back, then I'll know I have a problem.
I have a problem! The light is back on... I'll try to get the codes read tomorrow sometime, but I'm betting they're the same. It seems random, because today the idle was low and erratic even when the engine was warm. I'm gonna get a fuel pressure gauge and hook it up and see if that is a problem. Otherwise it looks like I may have to take it to a shop to get the computer calibrated? Any other options would be greatly appreciated. My wallet is empty right now, so I really don't want to fix what aint broke!
Here's an update: I've checked the o2 sensors and their relays (are there supposed to be fuses as well? Or are mine just box 5-pin relays?) I went ahead and replaced the front sensor and it's relay. I cleared the code and after about an hour, the CEL came back on. Before the light came back on, the engine was running perfect. But now it's running a bit rough at idle again, albeit not as bad as before. I pulled the codes and now I have 4! p0132, p0135, p0138, and p0141 (Both o2 sensors and both relays).... which tells me that it's something else.
A mechanic I know told me to check for a vacuum leak. I had already done so visually, but now I'll spray something on the hoses and check a little closer. He told me that since it's the exact same motor I swapped in, I shouldn't need to have the engine re-calibrated or anything.
Would an exhaust leak or intake manifold leak cause this? That would make sense because the bolts on the intake/exhaust probably need to be tightened now after 500 miles of break-in.
Any update to this? Mine is doing the EXACT same thing, same codes (except p0141) and I'm stumped. I replaced the front O2 sensor, repaired a frayed wire in harness for the rear sensor and I'm still getting the codes (though right now only p0135 and p0138) and it has the rough idle and stumbles like it wants to die as I'm driving it. Can't figure it out!
This may be complete coincidence, I flagged those same 3 codes for 2 years. I replaced both O2 sensors over and over. Check your mini fuses under the hood. I had a 15 amp that was bad. Replaced it and haven't had any problems since. IF.... that fuse has anything to do with the O2 sensors, when my driveshaft ate the harness the bare wires grounded and killed the fuse. I repaired the harness, resecured the wires, and started getting those codes. All anybody ever says is replace replace replace. I overlooked the small stupid stuff.
Hi I am also pulling up all of these codes. i would like to mention in my case i have had particular issues with the vacuum system in my 2000 xj. It controls alot more than i previously thought. replaced both o2 sensors a month ago and ran good for a couple days, then it started the same thing and codes came back... stutter and even backfire.Also pulled a code for EVAP P0443, wich is also related to the vacuum system. wondering if it is the pcm as i am having all sorts of electrical issues(back up lights out, speakers going in and out, shorts in lots of circuits)
Having same issues... Would be nice if someone got this fixed???
1997 Jeep Cherokee Sport
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