The problems with GDI

[SC Maintenance]

High octane fuel does nothing unless the compression ratio of the engine requires it. Running high octane in a low compression engine is actually ungood, since the fuel doesn't burn completely (octane being the resistance of fuel to compressive detonation) and leaves deposits behind. DI/TDI engines are normally high compression enough to need high octane, but not always.

Its not only compression ratio. Higher octane will allow controlled loop engines to use more timing advance. That is why you do get slightly better gas mileage with premium fuel - but its not enough of a gain to make it worth paying the extra money.

How any of that helps with GDI - I have no clue. I doubt its much difference.

 

[SubieRubyRoo]

I wonder on V or straight engines if you could pull the plug, rotate the engine to TDC so both valves are closed, and pour Berryman’s B-12 into the intake port and let it sit overnight? This should dissolve the goo and carbon, and then rotate it over a few times with the plug out so you don’t hydro lock it. You could even vacuum out most of the junk if you had the manifold pulled. Then repeat for the rest of the cylinders.

Just a thought.

 

[mrjlube]

Don't those have an oil bath timing belt?

No it has a timing chain. Had to check dealer service manual to confirm. Chain 100%






























Don't those have an oil bath timing belt?























T







If the timing belt breaks tell us, because some people want to know if they're any good

 

[JTK]

I wonder on V or straight engines if you could pull the plug, rotate the engine to TDC so both valves are closed, and pour Berryman’s B-12 into the intake port and let it sit overnight? This should dissolve the goo and carbon, and then rotate it over a few times with the plug out so you don’t hydro lock it. You could even vacuum out most of the junk if you had the manifold pulled. Then repeat for the rest of the cylinders.

Just a thought.

I'd imagine that would dissolve away some of the schmutz. I haven't fiddled with carbon removal myself on a GDI vehicle, but from the looks of it, mechanical removal is the only way. I'm sure all these chemical liquids and sprays available to use on a running engine do SOME removal, but they're not doing all of it. On top of that, what are these cleaners doing to your $3-4K worth of CARB compliant catalytic converters. That won't be an issue with mechanical cleaning.

As your average consumer, GDI does nothing beneficial for me, but yet here we are. The only way I would consider addressing intake valve build-up is if I had the intake off for some reason or if I had some issue caused by it.

I do early oil changes on my GDI vehicles because I don't like the way it blackens motor oil quickly. I'm on my 4th GDI vehicle and they ALL did this, where my port injected engines would keep the engine oil cleaner looking much longer.

Watch any engine tear-down video and GDI engines will always have some deposits somewhere, where you don't see it as much with port injection.

 

[buster]

What is the reason that manufacturers of GDI engines don't do what Toyota does with both Port and DI? Cost?

 

[IndyIan]

What is the reason that manufacturers of GDI engines don't do what Toyota does with both Port and DI? Cost?

Sometimes I wonder how much engineering expertise the manufacturers have? Or have testing budgeted for? Some of the mistakes/oversights are pretty significant? Or some manufacturers just don't care?
It seems toyota usually designs and builds for well beyond the warranty period, so they add a port injector system that only really matters at 100k+ and keep their reputation and rabidly loyal customers.

You would think GM Ford Hyundai/KIA VW Stellantis would have the budget to be able to design and long term test all sorts of things, but they seem to more often send some basic design or material mistakes into production?
Honda, Mazda, Subaru, do most of their own design and engineering with much smaller gross sales and seem to hold their own or outperform many of the larger manufacturers?

 

[buster]

Sometimes I wonder how much engineering expertise the manufacturers have? Or have testing budgeted for? Some of the mistakes/oversights are pretty significant? Or some manufacturers just don't care?
It seems toyota usually designs and builds for well beyond the warranty period, so they add a port injector system that only really matters at 100k+ and keep their reputation and rabidly loyal customers.

You would think GM Ford Hyundai/KIA VW Stellantis would have the budget to be able to design and long term test all sorts of things, but they seem to more often send some basic design or material mistakes into production?
Honda, Mazda, Subaru, do most of their own design and engineering with much smaller gross sales and seem to hold their own or outperform many of the larger manufacturers?

If it doesn't impact performance that much over the typical 5 year period, it could just be it's not of concern to the manufacturer is my guess.

 

[PandaBear]

Sometimes I wonder how much engineering expertise the manufacturers have? Or have testing budgeted for? Some of the mistakes/oversights are pretty significant? Or some manufacturers just don't care?
It seems toyota usually designs and builds for well beyond the warranty period, so they add a port injector system that only really matters at 100k+ and keep their reputation and rabidly loyal customers.

You would think GM Ford Hyundai/KIA VW Stellantis would have the budget to be able to design and long term test all sorts of things, but they seem to more often send some basic design or material mistakes into production?
Honda, Mazda, Subaru, do most of their own design and engineering with much smaller gross sales and seem to hold their own or outperform many of the larger manufacturers?

I think cost is one (injector, manifold, control algo development, almost double in cost for the parts in injector control, etc), the benefit is mainly in the combination of injection between them and improve part throttle efficiency. Eliminating intake valve deposit was just a side effect.

The main thing about these deposit is likely the valve overlap or temperature. I heard Mazda keep theirs hot so it doesn't form enough deposit before they get burnt off, and other manufacturers left a bit of valve opening so the fuel vapor get pushed back out during compression and would be enough to keep the valve clean.

Most of the deposit problem is from the early days, they don't have much problem in the newer engines now. DI improve mpg at high output but port injection is still better in mpg at part and low throttle.

 

[Bailes1992]

Don't those have an oil bath timing belt?

If the timing belt breaks tell us, because some people want to know if they're any good

Answers are out there if you google about the 1.0 Ecoboost.

The timing belts are disintegrating prematurely and blocking up the strainer on the oil inlet and starving the engine. Usually on strip down it is found that numerous teeth are missing.

I believe they’re having the same issues with the PSA 1.2 ‘Puretech’ engines too.

 

[Bill_W]

Interesting stuff!
So far we have remained GDI free but it seems some of the manufacturers are getting it figured out.

Mazda Skyactiv has an air/oil separator. (before the PCV valve) Still if there is a market you can be sold a can. (money before brains)

 

[odie]

KIA / HYUNDAI would probably void powertrain warranty if a oil catch is installed by the owner .

 

[JTK]

KIA / HYUNDAI would probably void powertrain warranty if a oil catch is installed by the owner .

I'm sure one being present would muddy the waters on a potentially associated repair, for any make/model that is under manufacturer's warranty.

I have a CC on my 2022 Frontier that is under warranty. I would surely remove it prior to any dealer visit. That would take about 5 min on this vehicle. This CC does catch oil. Maybe it helps some. No way of really knowing.

 

[buster]

I'm not sure catch cans help honestly. Even the Skyactiv engines end up with carbon buildup.

 

[buster]

Figure 12k miles a year on average/5y 60k miles. The amount of carbon buildup likely won't be significant enough to notice a difference in engine performance. Could hypothetically not even be an issue to much later years in the engine's life.

 

[dumkid]

I'm not sure catch cans help honestly. Even the Skyactiv engines end up with carbon buildup.

carbon buildup is mostly soot, glued together with oil. no soot=very little buildup. if you take the intake off of a pentastar with no egr, you will find it pretty clean except for a sticky oily film in the runners.

 

[burbguy82]

How any of that helps with GDI - I have no clue. I doubt its much difference.

It is harder to ignite

 

[burbguy82]

What is the reason that manufacturers of GDI engines don't do what Toyota does with both Port and DI? Cost?

Toyota plays the long game. I think this translates to good quality. I think cost is secondary with them, on some things.

 

[AdrianH]

I wonder on V or straight engines if you could pull the plug, rotate the engine to TDC so both valves are closed, and pour Berryman’s B-12 into the intake port and let it sit overnight? This should dissolve the goo and carbon, and then rotate it over a few times with the plug out so you don’t hydro lock it. You could even vacuum out most of the junk if you had the manifold pulled. Then repeat for the rest of the cylinders.

Just a thought.

I did this on a Tiguan 2.0T engine while it was out for tranny change. Possible to do while in car with intake removed. Heaps of gunk removed from top of valves this way.

 

[b_b]

me and my wifes car both have dual injection, never really thought about the intake valves. I do run injector cleaner through them periodically. since they have twice the injectors compared to standard port injected engines.

 

[picklyrickly1073]

I think DI is definitely more prone to these issues but can’t say with a broad brush that they all are equally prone. It depends on driving conditions, habits, maintenance, among others. Buddy of mine has a DI ford at 160k with no concerning buildup (he looked in with a scope) Another ran another ford to 270k and was ok as well. And then you see some absolutely trashed by 30k