4AGE/7AGE early rev-limiter and no power

[70XIN]

Hi guys, posting on behalf of a mate

I'm having a small drama with my engine. At the end of the last track-day i had a VERY minor power loss at around 6500-7000 revs, didnt think much of it (thought fuel surge)

My car now starts to shit itself/not climb in revs past about 3500, and if it DOES, it hits a pretty fast rev-limiter type thingo.

Driving around normally however it's fine. Just whenever you load it up.

What have i broken.

Thanks
Robo
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[70XIN]

after a bit of googling, it reckons 02 sensor could be causing it

will report back

[oldcorollas]

O2 is not used when engine is loaded up.. usually... since you don't want stoich under power..

[Munki]

check for ecu codes

[the_random_hero]

I can't remember if you're using a smallport or bigport head Seamus, if it's smallport the engine could be leaning out and knock sensor getting the shits? Did you check the AFR's with the ECU you are using?

[70XIN]

Bigport head, JDM AE86 ECU .. no knock sensors

We checked the error codes and got 9 (speed sensor) and 5 (02 sensor). We checked in the dark last night, and it doesnt appear that O2 sensor wiring/plug is damaged in any way, so maybe the O2 sensor has shit itself.

But as oldcorollas said, i wouldn't have thought the ECU would chuck very much of a hissy-fit over the O2 sensor.

[Ben Wilson]

Try fixing the speed sensor (it might think you are just free revving the car) and resetting the ECU and see how that goes.

[70XIN]

The speed-sensor has been a problem since the car was purchased (2+ years ago), so it's definitely not that mucking it up.

The O2 sensor code is definitely new though.

[Munki]

I agree with oldcorollas o2 sensor wont effect open loop since the ecu ignores once it leaves sustained idle or cruise.

I would check the basics first. I would check fuel pressure at idle and then under load.

other guesses could include damaged coil, timing gone to shit on dizzy?

Did you recently do anything to the car that might need checking over?

[oldcorollas]

i have vague memory that it does this if you swap the dizzy reluctor pickup to the opposite polarity...