Engine Carbon Clean - Any Experience ?

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Not sure whether to post here or in Engines and Drivetrain but looking for the general consensus.

Anyone had it done and noticed any difference/ benefits ? I'm looking at the hydrogen treatment (gas into the throttle body/ intake). Direct Injection petrol engine currently on 40k miles.

Local garage only charge £25. Seems rude not to.

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Hmm. OK, thanks for posting the video.

The pics showed that there wasn't much carbon removed from the valves but the car ran better with a microscopic gain in power.

That's what I'm looking for TBH. It's my wife's car, I don't drive it much but it has a slightly rough idle which my tinkering has not solved. I'll probably give it a whirl. It can't hurt I suppose.

Thanks again for posting the link. Much appreciated.

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GreenV8S said:

Red 4 said:

Direct Injection petrol engine currently on 40k miles.

If there's nothing else wrong, you shouldn't expect it to be coked up at that age. And if there is, decoking won't cure the problem.

I suspect you'd have more luck checking whether the ECU is detecting any misfires and whether the adaptive fuelling changes are reasonably small.

Pastie Bloater - it's a Mazda 3 2.0 Sport DISI. 60 plate. Owned from new and the car has done lots of short trips ! It does get taken for a good blast once in a while but as you can see the mileage is very low for the age.

It's been such a good car - precisely zero has gone wrong with it - that I'm loathe to get rid and just run it until it dies. My missus has no interest in cars but she does love it.

No codes showing, just a (slightly) shaky idle. Maintained to within an inch of its life. Very sooty exhaust though !

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Chainsaw Rebuild said:

What about filing it v power fuel on the grounds it has extra cleaning agent in it, and perhaps something like redex, and then taking it on a long journey? Worst case you have a day out somewhere.

Always run on Super (V Power or Tesco Momentum) and gets a shot of Redex if I fuel it (once in a blue moon).

It's had a couple of long trips recently (150+ miles at motorway speeds). It hasn't helped.

Recently had plugs, no codes. It just doesn't seem as happy as it usually is. It's fine under load (so have ruled out a coil on its way out) and drives great. It's just a bit grumpy at idle.

Thanks all. Advice is appreciated, as always.

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liner33 said:

Its only non sensible if you really believe a car with 40k has issues with carbon build up . The problem this car more than likely has is sticky injectors providing a poor spray pattern due to lack of use and short trips .

Some fuel with cleaning agents and a decent trip will most likely sort this.

EGR valves can be an issue on these cars with less than 40k. That's still a carbon build up issue. I don't think the short trips help due to the lack of heat to burn deposits.

I'll whip the EGR off and take a look.

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Update; didn't bother with the hydrogen carbon clean thing but did whip the EGR valve off and found it to be full of carbon deposits.

The valve wasn't closing properly which I think was confusing the car's computer, possibly over-fueling at idle and causing a slight pop from the exhaust.

One can of carb cleaner later and it's running sweet again.

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tapkaJohnD said:

OR,
Try this:
https://www.youtube.com/watch?v=xIijYgvxW0g&ab...

Reminds me of a song by The Prodigy.

That should be fine with a plastic intake manifold, shouldn't it ?