Faulty Knock sensor causing problems?

[SeriesIIGTST]

Hi all

On my R33 GTS-T, I recently ran an ECU diagnostics and it came up code 34 or knock sensor. Could this possibly explain why I have some good drives and some not so good drives power wise? How much of a difference in ignition timing does the knock sensor play part to? Ie, if my knock sensor is faulting and sending unusally high levels of knock (which aren't actually happening) to the ECU, could my ECU be pulling lots of timing out and causing my car to run like a dog?

It's very intermittant though, some drives, it'll have a great run with full power and all the usual acceleration, speed and lack of traction it should have, other times (exactly the same conditions), it will feel like it's loading up, boost will increase, but the car will be stagnant and not accelerate. Is this all the doing of a faulty knock sensor?

Any light you could shed would be appreciated. In the meantime, i'm getting a new knock sensor anyway.

Cheers!

P.S. I know the car isn't pinging, it's been tuned well and is making good power but not consistently as stated above.

[Mr GTS4]

yeah basically when the knock sensor throws a code to the ecu it will retard the timing alot. thats why when you hit like 5 grand it feels like you hit a wall. i had the problem for about 5months and didn't know what it was... found out and checked the sensors and one was disconnected. been great ever since.

[blind_elk]

Code 34 means that the knock sensor is disconnected or shorting. It does not indicate that the ECU has detected "knock" and retarded timing to compensate.

If it's intermittent performance, then it could be a break in the wire somewhere that makes the connection most of the time, but some condition causes it to lose the connection.

[EnricoPalazzo]

ur afm is maxing out. there is so much ariflow that the stock ecu pulls timing out, hence why u feel the car is making good power sometimes and shit power other. This happened to my car and whatsisnames car when we installed a unichip and wer makin around 210-220rwkws.

Solution is to buy a standalone ecu like powerfc as the standard ecu seems to be pulling alot of timing.

[SeriesIIGTST]

thanks for the replies. I thought it made sense that my knock sensor fault would cause timing to be removed. I've gotta get it up on ramps to check all connections now i guess.

Everyone tells me PowerFC and ultimately i want (need) one but i'd rather pay $2K off my loan than on one at the moment if it can be helped.

[Mr GTS4]

you don't have to put it up on ramps.. there on the intake side of the block just under the plemum*. in between cylinders 1-2 and 5-6. just check that their not hanging off .

[EnricoPalazzo]

im just curious on wat ur current setup is re turbo and ecu control. Are u using a SAFC?

[SeriesIIGTST]

Enrico - current setup is:

HKS 2535 GT Sports Turbine Kit

Trust FMIC

Bosch 910 fuel pump

Nismo adjustable FPR

Blitz EBC

Apexi S-AFCII

So yeah, basically S-AFCII + Stock ECU

[EnricoPalazzo]

yeh obviously u should be lookin at a proper ecu, ie powerfc, wolf3d or microtech.

Then u wont have the shit problems u have now, aswell as heaps more power from being able to adjust igniition.

[SeriesIIGTST]

Thanks for all the replies

Sure enuf, put it on a hoist (just easier) and there was my front knock sensor hanging loose (not off, just loose). Have plugged it back in, made sure it's totally secure and BOOM, power all over the place again Tried another ECU diagnotic and got a code 55 - all clear

Car is pulling violently all the way to redline again, breaking traction all over the place and generally being great fun to drive. :burnout:

If it's this good with S-AFC + Stock ECU, can't wait to get PowerFC or Wolf and see what happens.

My advice: Do not underestimate your knock sensors and the simply ECU diagnostics...gives a great insight into what could be wrong before resorting to a mechanic