Topic: Why fuel injector cleaners will not work on gdi engines

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stc954
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Topic: Why fuel injector cleaners will not work on gdi engines

Post by stc954 » Wed Jan 08, 2020 1:50 am

Hello people. I have been wanting to write about this subject for a long time so here it goes.

Car of the subject
Astra k 2017 1.4T Petrol

Topic
My analogy of why fuel injector cleaners will not work on these GDI engines

The analogy
Let's start with the basics, as shown below in a gasoline direct injection system, fuel is sprayed directly onto the cylinder header. The intake valve never makes contact with fuel or any cleaner.

Image

Compared to systems were the fuel is injected into the back of the intake valves, those intake valves are always clean because gasoline is a good cleaner i.e. a solivent. Accordingly, it makes good sense to use those systems fuel cleaners to further help in cleaning and maintaing the intake valve etc.

However, what are we trying to acheive with Gdi engines? You can put all the fuel cleaners in the world EVEN OEM and The intake valve will get gunked up. I seen people buy OEM fuel injection cleaners on this form, but what are we trying to acheive exactly?

In some way, yes it is cleaning the injectors. No doubt. However, that's only true if THE CLEANER IS USED UNDER THE CORRECT CONDITIONS. Such as fuel to cleaner ratio etc...

What are your opinion guys?

Markot1989
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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by Markot1989 » Wed Jan 08, 2020 8:25 am

So if you are using decent quality "premium" fuel, which to my understanding already had detergents in them, then there isn't any real point in using something like STP / Redex?

By Premium I mean something like 97 RON BP Ultimate rather than standard 95 Ron Unleaded.

astraowner
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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by astraowner » Wed Jan 08, 2020 9:00 am

Markot1989 wrote:
Wed Jan 08, 2020 8:25 am
So if you are using decent quality "premium" fuel, which to my understanding already had detergents in them, then there isn't any real point in using something like STP / Redex?

By Premium I mean something like 97 RON BP Ultimate rather than standard 95 Ron Unleaded.
You might be right, but it will still be additives in the fuel and not the higher RON value that does the trick.
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Finston Pickle
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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by Finston Pickle » Sat Jan 11, 2020 7:49 pm

Based on myexperience, and if you are going to keep the car for more than a couple of years, I think that all GDI engines should be run on the "Premium" petrols. You get better life and more power or better consumption - take your pick.

Why the manufacturers and others infer that any petrol is OK with GDI engines (by not saying "please use Premium petrols"), is beyond me.
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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by Redman » Sat Jan 11, 2020 8:25 pm

Look at the carbon on this piston from a 1.4t astra k for sale on eBay. This is why my car has always been run on shell v power 99 Ron, in the hope to prevent/reduce this. I would like to think the cleaning detergents in these premium fuels clean the pistons.
Carbon build up at the back of the inlet valves won't drastically contribute to lspi imo. It will eventually disrupt airflow into the cylinders

Screenshot_20200111-201201_Samsung Internet.jpg

Screenshot_20200111-201156_Samsung Internet.jpg

Screenshot_20200111-201201_Samsung Internet.jpg


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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by Redman » Sat Jan 11, 2020 9:07 pm

This is a different piston listed for sale on eBay. Have no idea of mileage any of the piston have done or what fuel they ran on. This one seems cleaner, may have been cleaned but have visible evidence of carbon.

Screenshot_20200111-210205_Samsung Internet.jpg


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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by Finston Pickle » Mon Jan 13, 2020 7:42 pm

Wow, that photo reminded me of the 60's when cars needed a decoke at 10,000miles.


Let's hope that the Premium petrols that I use are doing their work in keeping things clear.
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stc954
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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by stc954 » Mon Jan 13, 2020 8:08 pm

Hi guys, I was doing some reading on this forum to also prevent this further, replace your PCV valve, I read online it is every 20,000 miles.

I always put the expensive petrol, just so I can sleep at night :lol: .

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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by MOOGLEYS » Mon Jan 13, 2020 8:28 pm

Good old fashioned Italian tune up blow that nasty carbon away...... 😀

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Re: Topic: Why fuel injector cleaners will not work on gdi engines

Post by Crosseyxpower » Mon Jan 13, 2020 9:20 pm

Guys have you thought that these pistons in the pictures have come from a engine where lspi has probably occurred in one of the cylinders? This would put strain on the remaining three and cause excessive wear and fuel plus other aspects. The best way to truly see what is happening is to have a camera down through the spark plug hole. There are many vids of this on YouTube and i can seem to remember tests being down using injector cleaners, decoke cleaners and premium fuels making no remarkable difference over time.

I've ran my engine on plain old 95Ron from day one and have had no issues coming up to 40k miles. Best advice is to stick to the oil changes and just drive with care. The extra 10p a litre just doesn't seem worth it to me.

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