reyanth

Hi! So as the title sais I'm having issues with ma doch mugen's (EP3 Type r 2002 K20A2) VTEC. Engine has 235k km (135k miles..ish) on the clock.

As far as I know there are only few mods on the car in case you need to know:
- Freelow air filter
- Custom exhaust with cat, OEM manifold

Issue:
Around 6000rpm when the VTEC is suppose to engage the engine makes a grind noice and hesitates BEFORE the vtec actually kicks in.
- The ginding noice is worse depending on throttle input. More throttle -> Perhaps more longer grind before vtec engages.
- If you cruise over the 6000rpm area with gentle throttle, there is no grind noice and vtec works.
- If you shift down so the rpm jumps over 6000rpm, there is no noice and vtec works.
- When accelerating and engine making noice around 6k, if you lift throttle a bit it makes the noice go away faster.

Current:
- New engine oil and filter (oil level check ok!)
- Engine running temp around 88-90c (180-195f)
- Idle rpm around 900 and smooth
- Battery voltage on 12.6v-ish, when charging around 14v-ish.
- No leaks, does not burn oil nor water.
- Throttle a bit hesitant on low % throttle acceleration. 0.5-1sec "lag/hesitation" before engine starts to pull.
- No warning lights on dash
- No fault codes

Not sure what else to say, but I'd really want this vtec gremlin sorted out! Thanks!