M35 Power Drop

[knightdesigns]

Hi i have a 2001 250t rx and it has recently begun to act a bit strange.

The car has always driven great, and been a rocket generating plenty of thrust in the top end, however recently when i was coming up Mt Vic, it suddenly dropped power/boost and seemed to be only running at about 75% of it's normal output.

I thought at the time the ecu may have dropped power due to things getting hot ? however my temp gauge was all good.

I backed off and pulled over, restarted and as i went over the top of the Blue Mtns it seemed to come good and bounce back, so i thought it may have been a temp thing.

Over time its started to do it more regularly, to the point i thought i may have had a blocked exhaust/ cat etc as i also noticed one of the pipes coming out of the muffler tip didn't seem to be flowing at all.

I visited my exhaust guy and we pulled the pipe off at the cat and pre muffler and took it for a run and still no improvement, so i guess we can eliminate the exhaust.

However a system scan of the car revealed a fault with the knock sensor.

Could this be the culprit ?

any help would be appreciated

cheers

[Commsman]

What was the exact code?

Faulty knock sensor could do it I suppose. If the ECU retards the timing heaps it will feel down on power. You didn't just get a bad tank of fuel (I once bought premium & got standard)?

[joshm35]

Read this. Try and use the search function.

http://www.skylinesaustralia.com/forums/topic/427603-somethings-not-right-here/#entry6905983

[knightdesigns]

Commsman

I thought it may have been fuel, but had some new fuel and injector clean through it since.

I had a fault code come up as well C 1208 Pressure switch

thanks guys

[knightdesigns]

Joshm THANKS !

i think that link described the problem almost perfectly

i'll make sure the knock sensor is ok then look at the boost solenoid

can anyone tell me the location of ....

the knock sensor

the boost solenoid

and where i can buy them ?

thanks again

[joshm35]

Boost solenoid is on passenger side of engine half way to the back of the engine beyween the block and aie intake hose. Its held on by 10mm bolt with 2( 7mm) hoses going into it. Hope tjis helps. Theres a pic somewhere on here that shows it

[joshm35]

This will help you

http://www.skylinesaustralia.com/forums/topic/370714-m35-boost-bleed-valve/?hl=m35%20boost%20controller

[scotty nm35]

You don't want to change the knock sensor, it's a fairly big job as it's down in the valley, under the intake lower plenum.

If it hasn't thrown a code then the ecu is simply trying to ruin your fun. Bypassing the solenoid will stop this, just get a joiner and plug the two vac lines into each other. (Don't replace them as there is a restrictor on one.)

[knightdesigns]

Thanks Scotty and Josh, i'll let you know how it goes : )

running this mod won't cause any long term probs will it ?

[joshm35]

No ive had mine completely removed and unpluged for almost a year now without and issue or fault code.

[knightdesigns]

Thanks for the info guys, by passing that boost solenoid, fixed the issue

cheers