Hi, Jonathan.
Looks like someone replaced your gauge plate.
With JDM, where the triangle marker sits on your gauge, it should show the marker for the CAT high temperature warning.
It's ' sort of ' equivalent to the rapid blinking CEL on full OBD2 car when too much unburnt fuel entered the CAT.
Are you still using the JDM spec CAT?
There is a silver stick like temperature probe on each CAT.
The mating connectors are mounted next to the RR w/speed sensor behind the boot carpet at the forward right corner of the boot.
Please note that if you have ACG charging system failure, both the battery marker and this CAT high temperature warning will be triggered at the same time.
Please do not keep running the engine at the same load for long period when this warning is triggered.
Otherwise, it will melt down the honeycomb structure inside the CAT body.
If you saw it while driving, please slow down (like 50% of the speed you were carrying) until the warning light disappears.
If it happened at idle rpm, please park the car where no flammable materials are under the car and stop the engine for more than 10min to cool down the CAT.
As you suspected, you really need to measure the fuel pressure while the issue is present otherwise it could lead to wrong diagnosis.
If the fuel pressure is fluctuating but not enough to trigger the CEL, then due to the delay in O2 feedback control loop and only two O2 sensors for 6 cyl engine that several cyl will be getting very rich mixture.
Or, you may not have fuel pressure issue but instead, having intermittent multiple cyl IG issue due to ignitor failure, IG coil, etc resulting in misfire that is not consistent enough to trigger the CEL and allowing so much unburnt fuel entering the CAT.
Even with the full OBD2 spec ECU with 3pin IG coil and misfire detection module (yours is pre-OBD2), I know from the fact that it couldnĀt detect intermittent misfire caused by the IG coil triggering rapid blinking CEL but no continuous CEL and thus, no error code despite the big misfire that anyone can feel.
If O2 sensor is sending intermittent wrong voltage data, again, it could result in similar issue without triggering the CEL but normally, it's hard to make the CAT so hot without triggering the CEL if the issue was caused by the O2 sensor.
Still, there is a chance of multiple issues of mixture and IG....
Again, hope you can measure the fuel pressure while the issue is happening on the engine.
Kaz
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Originally Posted by Kaz-kzukNA1
