GDI carbon build up

My question is how are people dealing whit the carbon build up on the intake valves on GDI engines especially turbo charged. from what little i have heard a conventional Induction flush is bad for the turbo. I'm not sure about non turbo? I have seen a company that makes a blaster that uses walnut shells and an attachment that fits the intake runner and a shop vac so you can blast it and vacuum it at the same time. So far they only have attachments for BMW and MIni. I know that the problem is out there and I would like to hear what experience anyone has with it?

Not sure about a the conventional flush machine being bad for the turbo, haven't heard that before. :huh: But we've had good luck Motorvac cleaning fluid in a pressurized can with a long nozzle. Tuck the nozzle into the throttle body and add carefully with the engine running.

It takes a few applications, and the engine doesn't like it (since the fluid itself doesn't burn), but it's been effective in fixing cold start misfires on GDI engines.

I just had a Mazda GDI that had carbon build up on the valves in the shop today. It was causing a slight misfire at idle (non turbo). I had already made a walnut blaster with a Harbor Freight sandblaster with walnut media. Cost less than $100 to build. For the business end I used a long metal valve stem that I hollowed out and I use a large diameter heater hose for the vacuum attachment. Does a real good job of cleaning that valves. I made it for a Mazda with a turbo that would backfire through the intake under boost. I will have to take some pics when I get back to shop.

Ro-longo wrote: I just had a Mazda GDI that had carbon build up on the valves in the shop today. It was causing a slight misfire at idle (non turbo). I had already made a walnut blaster with a Harbor Freight sandblaster with walnut media. Cost less than $100 to build. For the business end I used a long metal valve stem that I hollowed out and I use a large diameter heater hose for the vacuum attachment. Does a real good job of cleaning that valves. I made it for a Mazda with a turbo that would backfire through the intake under boost. I will have to take some pics when I get back to shop.

Cool! I've heard of this before but never actually seen it. So definitely post some pics

I'd like to see picks of it too

I was having a similar discussion the other day, and we got somehow to the point of wondering if maybe a fine misting of just regular water through the throttle body or intake vacuum would kind of steam clean the backs of the valves.

I know it sounds counter intuitive, but I can remember seeing some old timers pour water very slowly into carbureted engines for a decarbonizing effect.

Steam or water mist tretment would be worth trying.
Engines running on LPG or CNG also suffer from intake valve issues due to the dryness of the fuel. To overcome the problem in r engines that are particularly you can buy kits to inject metered volumes of upper cylinder lubricant into each intake port.

If i understand right the problem with running anything through the intake is not the fluid so much as the carbon that comes off and gets processed through the turbo. Also i did an induction flush with Wynn's cleaner right before i pulled the intake. I was surprised to see how gummed up the inside of the intake was. I had to clean the goo out of the variable intake runner valves. It was a lot so I'm questioning intake flushes anyway. I can see were the goo i saw wold be bad for a turbo especially a variable vain one. I would like to see some pictures of that home made blaster too. Bavarian Autosports has a video on you tube showing the one they make. It seems like it might work? and i think you could make an adapters for different intake ports. I know BG makes a kit that basically you pull the intake and scrape the carbon off and vacuum it up or blow it out. I know that i will start seeing a lot of theses soon and it just seems like there is an easier way.

I see what you're saying about freeing up all that crap only to be digested by the turbo.
It sure would be a nightmare to wreck a turbo during a relatively routine maintenance procedure...

Ok, here is my setup.

First image is of the tank .



Here is the Vacuum hose adaptor



A view of the nozzle made from a long metal valve stem that I drilled out.



A view with everything put together



And this is from the first time I used it on a Mazda 4 cylinder GDI Turbo. The valve on the left if after cleaning and of course the one the right is before using the blaster. I had previously tried to clean the valves by soaking them over night in Seafoam (It didn't do anything but make a mess)

Here are the links for the parts

20 lb. Pressurized Abrasive Blaster

25 lbs. Walnut Shell 24 Grit Fine Abrasive Media

I added a water separator that we had in the shop, without it the nozzle would clog up.

I need to add a pressure regulator to the set up,

Ro-longo wrote: Here are the links for the parts

20 lb. Pressurized Abrasive Blaster

25 lbs. Walnut Shell 24 Grit Fine Abrasive Media

I added a water separator that we had in the shop, without it the nozzle would clog up.

I need to add a pressure regulator to the set up,

That's pretty slick, sir. The results speak for themselves!

Holy crap! That result is night and day difference Ro-longo! Thanks for sharing this.