scoobaru mad

iTrader: (2)

The car:-
I have an O2 Bug WRX, with alot of mods. 55k miles regularly serviced, oil changes etc

It as the title says really. For normal round town driving it rarely happens, but raise the revs a little, when you change gear, the cel light will flash for like a split second? And if your really open the taps up. Sometimes through 3rd (bout half way through 3rd) the cel will stay on, till you change up to fourth.

Then it goes out, BUT, half way through 4th, same again. An when this happens, you can feel the power drop slightly. Light goes out, power returns?

There is no fault codes stored either

Car drives fine, no noises or issues.

I had the idea that 'maybe' the FMIC (its touching the under skin of the bonnet) that could be causing the knock sensor to listen to the wrong thing.

Same as my induction kit too really. (Soon to be changed an sorted)

Ive heard the bug WRX has a sensitive knock sensor. Is this correct?

Anyway, any info would be great. Cheers guys

Chris.😀

piehole1983

iTrader: (7)

I think you are on the right line with the knock sensor picking something up, the power loss does seem to be the timing being retarded to stop knock happening.

I'd have it checked for knock by someone who knows what they are listening for before anything nasty happens, especially as it only really happens under higher loads. Have you been using good fuel? Is there a possibility you got a bad batch of super or filled with regular unleaded?

piehole1983

iTrader: (7)

Oh and the knock sensor picks up all noise but it's signal is filtered by the ECU to pick up a particular frequency range, the range that a knock/ping produces. While I know that other factors can trigger a false alarm, I doubt the FMIC or pipework would trigger a knock signal by physically touching the bonnet.

You may well have a dodgy knock sensor like I did, but mine just put the CEL on and it stayed on all the time. The fact that yours flashes would likely indicate it's working.

Has the car been remapped for all the mods it's had??

scoobaru mad

iTrader: (2)

It only ever has v-power nitro, or 99 momentum.

I try to be one of the good owners what she needs, she gets!

When it was getting mapped. He said he could hear the box on one of the power runs, an sure enough, the cel came on momentarily.

An it was suggested that the sensor may have to be moved.

Also, my mate had a bug STI, an was informed that the knock sensor were particularly sensitive on this year. Wether that was for the STI version only, I don't know?

The maps been checked once, an everything was tip top. BUT, Im thinking of upgrading the oem 3 port solenoid to an after market one. So I can get the map checked again then.

I'll be checking over the engine bay this morn. Try to locate any further rattles etc.

Cheers dude