Symptoms of dirty intake valves on DI engines?

[Elkins45]

How would someone know if the intake valves on their GDI engine need cleaning? I have two vehicles with DI engines and I want to make sure I'm alert to early signs of problems before they become significant.

I'm told that Mazda did some sort of voodoo with the Skyactiv-G that helps it keep the valves clean, but I doubt Nissan did and I need that V8 in my Titan to last for at least a decade more LOL.

 

[oldhp]

My wife complained, her bought new 2012 Equinox 2.4 didn't wanna go when she stepped on the gas. Yep, I drove it, waaaaay down on power. Didn't even want to fight dealer and warranty. Traded for a Jeep Wrangler. Wife was happy. Never went over 2500 miles oil change, filled with SHELL V-Power at least every third tank. Didn't do any good.

 

[Jetronic]

yes, power loss.

if you have a scantool that shows live data or logs it, make a log of air mass vs boost and rpm(for a turbo) on full throttle, or just full throttle and rpm (non-turbo). That way you have a reference and can periodically check.

 

[ka9mnx]

And rough idle...

 

[SC Maintenance]

Rough idle, power loss, burns more fuel.

If you really want to know pull the intake. I don't think the Nissan's are knows for this to be a problem. How many miles on the Titan?

 

[Patman]

And rough idle...

That could be tough when it comes to my direct injected LT1 engine in my Corvette because it already has a rough idle due to the camshaft profile. A lot of new C7 owners come into the forums complaining of a rough idle only to find out that it’s normal and they all are like this

 

[BMWTurboDzl]

How would someone know if the intake valves on their GDI engine need cleaning? I have two vehicles with DI engines and I want to make sure I'm alert to early signs of problems before they become significant.

I'm told that Mazda did some sort of voodoo with the Skyactiv-G that helps it keep the valves clean, but I doubt Nissan did and I need that V8 in my Titan to last for at least a decade more LOL.

The vehicle starts running rough.

 

[ka9mnx]

That could be tough when it comes to my direct injected LT1 engine in my Corvette because it already has a rough idle due to the camshaft profile. A lot of new C7 owners come into the forums complaining of a rough idle only to find out that it’s normal and they all are like this

I wasn't referring to "boutique" vehicles.

 

[Elkins45]

How many miles on the Titan?

Less than 50k. If it’s a problem it will probably be a few more years before it shows up.

 

[supton]

I'm starting to wonder if our hybrid might have some DI deposits, it just doesn't sound quite the same. But wife hasn't noticed so I'm apt to wait until the mpg's drop, it's not a job I could do myself, I don't think.

Speaking of, I elected to go 10k on an oil change and... that 0W16 was nasty coming out. And there was more in there than I put in. Won't do that again. Maybe my PFI Corolla can do 10k (haven't tried) but I sure won't do that going forward with any DI.

 

[Faawrenchbndr]

How would someone know if the intake valves on their GDI engine need cleaning? I have two vehicles with DI engines and I want to make sure I'm alert to early signs of problems before they become significant.

I'm told that Mazda did some sort of voodoo with the Skyactiv-G that helps it keep the valves clean, but I doubt Nissan did and I need that V8 in my Titan to last for at least a decade more LOL.

Usually around 150k miles
Rough idle….or a miss
If really bad, can cause a code to pop up
Low power, loss of acceleration

Really only way to tell is to use a boroscope to actually see the chambers and back sides of valves

 

[walterjay]

Rough idle. A 2,000 mile interstate trip in mid summer cleared it up.

 

[Bladecutter]

Pull spark plugs,
rotate engine until the cylinder you want to inspect has its intake valves open,
stick borescope into opening, and inspect the intake valve condition
rotate engine, and repeat until all cylinders have been inspected

 

[Elkins45]

Pull spark plugs,
rotate engine until the cylinder you want to inspect has its intake valves open,
stick borescope into opening, and inspect the intake valve condition
rotate engine, and repeat until all cylinders have been inspected

That's not a symptom. That's a diagnostic.

 

[Hohn]

I would get an occasional off-idle hesitation on my GDI-only IS250 with the somewhat infamous 4GR-fse.

The duty cycle of the car: drive 23 miles to work in the morning on two lane 55mph hwy. Drive 10 min to lunch and 10 min back. Drive 23 miles home from work. Repeat this day 3x weekly (I'm working from home monday and friday). A couple evening errands and sometimes weekends.


This was the duty cycle that led to the off-idle hesistation. A single trip to retrieve Daughter from college (3hrs each way) and the hesitation was gone for months.

Seafoam through the intake would yield tangible improvements in response, but they were short lived and the hesitation would return.

It would behave just like an old carbureted engine with insufficient choke or accelerator pump shot-- stumble just off idle, then catch itself.

Probably the O2 sensors starting to fade since the car had 186k on it.

 

[JTK]

IVDs on GDI engines are a problem the manufacturers are aware of, and some take actions to mitigate it w/ port and DI injectors, valve timing, etc.

I know we stress about it on BITOG all the time.

On the other hand, has anyone on BITOG ever reported IVDs severe enough to cause an issue that was corrected only by a manual cleaning, etc, and no other services?

IMO, it's a situation you consider when pulling the intake to replace spark plugs, or if the intake has to come off for any other service. IVDs are always going to be present no matter what you do on GDI.

 

[Bladecutter]

That's not a symptom. That's a diagnostic.

That's not what you asked for in your very first post.
You asked this:

How would someone know if the intake valves on their GDI engine need cleaning?

A number of the symptoms provided by the other posters can also be caused by something other than valve deposits, which might mask the issue to you until it's way more of a task to deal with.
And, there's no better way to know if you have deposits than by looking.

 

[MCompact]

How would someone know if the intake valves on their GDI engine need cleaning? I have two vehicles with DI engines and I want to make sure I'm alert to early signs of problems before they become significant.

I'm told that Mazda did some sort of voodoo with the Skyactiv-G that helps it keep the valves clean, but I doubt Nissan did and I need that V8 in my Titan to last for at least a decade more LOL.

The GDI turbo in my 2007 Mazdaspeed 3 was supposed to be vey susceptible to intake valve deposits, but when I flipped it in 2016 at 158k miles the performance had no degraded- based on in-gear acceleration times.