Direct Injection Engine - Intake Valve Cleaning

[ER-3682]

On 5/31/2026 at 12:22 PM, Enye said:

Mine also dual injection with turbo at 80k km

 no plans to do walnut blasting or adding any additives.

 Just pump good quality petrol can le 

😬

98 Petrol for my Camry...but not V-Power..just SPC Levo.

[ER-3682]

On 5/31/2026 at 12:38 PM, inlinesix said:

If got misfiring and not because of spark plug, walnut is the only solution.

PEA is the best solution to remove carbon deposits.

The proportion of PEA in petrol is usually unknown.

I believe there is no difference in quality of our petrol.

But Shell V-Power & Caltex Platinum are really a tad better.

[Enye]

On 5/31/2026 at 12:38 PM, inlinesix said:

If got misfiring and not because of spark plug, walnut is the only solution.

PEA is the best solution to remove carbon deposits.

The proportion of PEA in petrol is usually unknown.

I believe there is no difference in quality of our petrol.

I meant good quality petrol in Malaysia by choosing the bigger and newer petrol stations there to avoid possibility of contaminated petrols 😬

no concerns in Singapore as I pump 95 in sg

😅

[Enye]

On 5/31/2026 at 1:04 PM, ER-3682 said:

98 Petrol for my Camry...but not V-Power..just SPC Levo.

No need 98 for me… save money

 engine is on ron95 tune

😅

[inlinesix]

On 5/31/2026 at 1:09 PM, Enye said:

I meant good quality petrol in Malaysia by choosing the bigger and newer petrol stations there to avoid possibility of contaminated petrols 😬

no concerns in Singapore as I pump 95 in sg

😅

Go Malaysia pump RON100🤭

 

[Ake109]

On 5/31/2026 at 8:06 AM, ER-3682 said:

Anybody know,for Toyota Dual Injections Engines,running on low Rpm is using Port Injection or Direct Injection.?

Start-up and Low rpm should be port.

Previously, I cleaned my Audi 3.0 Supercharged, it wasnt running rough at near 100k but when the mechanic opened it, I could see a huge amount of carbon gunk on the valve seats. After walnut blasting, it was all clean but frankly, my butt dyno couldn't tell the diff before and after.

Edited June 2 by Ake109

[ER-3682]

On 6/2/2026 at 9:10 AM, Ake109 said:

Start-up and Low rpm should be port.

Better,because of Hybrid,my Revs seldom go above 2,000Rpm.

[Ake109]

On 6/2/2026 at 9:16 AM, ER-3682 said:

Better,because of Hybrid,my Revs seldom go above 2,000Rpm.

 

https://www.sema.org/news-media/enews/2007/31/twin-injection-engine-one-10-best-says-wards

 

The PFI system typically operates on its own during the actual cranking part of the engine startup phase. It is during this time that a substantial portion of the “raw” emissions of a cold start are produced. During high-load operation, only the DI injectors are used, which maximizes the DI’s ability to deliver a cooler and denser air/fuel mix. This promotes maximum power and torque.

Edited June 2 by Ake109

[Kklee]

On 6/2/2026 at 9:20 AM, Ake109 said:

 

https://www.sema.org/news-media/enews/2007/31/twin-injection-engine-one-10-best-says-wards

 

The PFI system typically operates on its own during the actual cranking part of the engine startup phase. It is during this time that a substantial portion of the “raw” emissions of a cold start are produced. During high-load operation, only the DI injectors are used, which maximizes the DI’s ability to deliver a cooler and denser air/fuel mix. This promotes maximum power and torque.

IMHO.
My Corolla Cross Hybrid D4-S,  during cold start if engine is triggered,  DI for about 30 secs and thereafter is PFI only for another 30 secs or slightly more before cut-off.
I am not sure during the cold start ( when engine is triggered ) when DI is active, is PFI active as well. 

[Gnahp]

On 6/2/2026 at 9:10 AM, Ake109 said:

Start-up and Low rpm should be port.

Previously, I cleaned my Audi 3.0 Supercharged, it wasnt running rough at near 100k but when the mechanic opened it, I could see a huge amount of carbon gunk on the valve seats. After walnut blasting, it was all clean but frankly, my butt dyno couldn't tell the diff before and after.

me too

I couldn't feel the difference (lack of) in power when it is choked 

if not because of the occasional misfire during acceleration, I wouldn't know the valves are full of gunk 

like you said, no difference in power before and after walnut blasting