Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
If you have the two precats and the 4 o2 sensors, 2 before the precat and 2 after the precats then there is no 5th o2 sensor behind the main cat.
1998 4.0 swap into 2000
- Thread starter Showtime3492
- Start date
Showtime3492
NAXJA Forum User
- Location
- Pennsylvania
So i ran into another problem today. I have all my o2 sensors i just didnt realize they were up on the exhaust manifold... So heres my question because i cant use the 2000 manifold on the 1998 what do i do about the two upstream cats that are built in to the exhaust manifold?
Showtime3492
NAXJA Forum User
- Location
- Pennsylvania
This is what i have any ideas on what i can do to relocate them so that they will agree with a 1998 motor that consists of 2 o2 sensors one on the manifold one after the cat?.. I was looking at it and it looks like the harness can be swapped out that holds the wiring for the o2 sensors it appears to go from the pcm to the injectors and then down to the o2 sensors and back by the transmission..:dunno:
- Location
- Rainy side of Washington
You'd have to swap the ECU and wiring harness to make it work with the older O2 sensor setup, unfortunately. I'm not even sure if that's legal for over the road vehicles.
What I would do is install additional O2 sensor bungs in the older manifold. Can buy them at speed shops and on summit racing, and it's a ~5 minute weld job. Just make sure you don't locate them somewhere they will run into the intake manifold when you install it.
What I would do is install additional O2 sensor bungs in the older manifold. Can buy them at speed shops and on summit racing, and it's a ~5 minute weld job. Just make sure you don't locate them somewhere they will run into the intake manifold when you install it.
Showtime3492
NAXJA Forum User
- Location
- Pennsylvania
I thought about that but what i am worried about is passing Pennsylvania emissions. Wouldnt that throw the check engine light cuz it has the pre cats and o2s?
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
The older manifold won't work with a 2000 down pipe with the precats. The precats are in the down pipe, not the manifold.
That will throw a check engine light and you probably won't pass inspection.
You have two options.
1) use an earlier manifold/ header and have the precat O2 bungs welded in, but the manifold has to be a tri Y style so the bungs can be welded so the front O2 sensor monitors the front 3 cylinders and the rear O2 sensor monitors the read 3 cylinders. Then you would have to cut your stock down pipe off with the cats and have a custom down pipe bent up. Once that is done you need to do something about the after cat sensors. Sim them out in some fashion or put them after the main cat, which may not work. Removing the precats is also illegal.
2) Get a 2000+ header and hope it covers the 0630 head ports. I have not verified this myself, but I have been told by reliable sources that the pipes are big enough to cover the 0630 head ports. You keep the precats and the O2 sensors bolt in fine.
- Location
- Rainy side of Washington
Now I'm confused. I thought you said the 2000+ headers didn't work well with the ports on the 0630 head - isn't that what the tracings you posted on the first page of the thread showed? I'm probably missing something here.
- Location
- Minneapolis, MN
Use an 0331 head, or Search one of the many threads that show how to adapt and use an 0630 or 7120 head on a 2000-01 Cherokee.
Here is a freebie Google result -> http://www.naxja.org/forum/showthread.php?t=919384
Here is a freebie Google result -> http://www.naxja.org/forum/showthread.php?t=919384
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
That is what I said earlier. The stock manifold won't line up well. The after market header should work.
Header is different from manifold as is stock from after market.
