[Paulw]

Has anyone had this fault before on a jimny?
Looking at the sensors on the obd reader looks like the pre-cat O2 reading is all over the place and the post-cat one is nice and steady so I was going to order one in to replace it.
If any one has had the same problem please let me know what was the fix for you?

Cheers,

Paul

[royce]

the pre cat one will go from 1v to 0v and back again quickly while in closed loop (cruising and idle) and will sit at 1v while accelerating

the post cat one will be a bit more damped but sit around 0.8 when in closed loop

obd readers are too slow to read them properly, are the fuel trims really high?

[zukenutter]

Are you still running the S/S header Paul?

[Paulw]

Thanks Royce the Fuel trim is ranging from 2.34% to 3.91% at idle, I've reset the code and so far the fault hasn't reappeared.

Quote:

Are you still running the S/S header Paul?

Yep, did you mention it was causing an issue on Tardis?

[shandy92]

Try swap sensors back and forth and see of the strange readings follow with the sensor. If it goes with the move then change the sensor ect.

[zukenutter]

Yep, I believe so. The depth of the sensor mount causes the flow of gas passed the sensor probe to be partly interfered with. Here's the comment...

zukenutter wrote:

A bit of perspective. The photo below shows the extractor that Jezza and I are running on the left and the OEM manifold on the right. The OEM has a simple threaded hole up close to the head, the extractor has the mount down near the flange after the final merge. In this pic the plug is still in place so ignore that, but you can see how thick the threaded sensor mount is.

Also compounding my issue was the different design of the aftermarket sensor

zukenutter wrote:

I swapped the #1 oxy sensor today from aftermarket back to the OEM I had in a box, and also swapped back to OEM manifold, now she's running sweet with no dead spot or lag. Not sure which was the problem so I'll swap the sensor again and compare but the probe is quite different to OEM.

The aftermarket sensor was very black and sooty, been running a bit rich. I'll leave it like this for a while and see how it goes.

My plan is to grind down the sensor mount on the header by half.

I haven't thrown a code since swapping to factory manifold and genuine O2 sensor, Touch wood!!.

[Paulw]

Thanks Paul, I'm gonna take the sensor out and give it a clean with the blow torch and while it's out test it with a multimeter. If I feel game might do the same and grind down the mount as well.

[zukenutter]

I still haven't attacked my header, done yours yet Paul?