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sprinkles08, ASE Certified Technician
Category: Volvo
Satisfied Customers: 21439
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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I am having problems with the fuel intake system fouling.

Customer Question

I am having problems with the fuel intake system fouling. mechanics have recommended premium fuels to prevent deposit building up in the air fuel mixing chamber. I would like to learn to clean the deposits myself to lower maintained costs on my 2006 XC90
Submitted: 3 months ago.
Category: Volvo
Expert:  rpmdiag replied 3 months ago.

Hi, I’m Ron and I’ll be helping you today.

Before we get started though, please understand that I don't know your skill level or tools you have to assist us. Also understand that I can't see,smell, hear, or touch the vehicle either, so patience is appreciated.

My goal is to make you happy and get a great rating in return for my time.Sometimes I have to give you bad news that I know you didn’t want to hear, so please don’t shoot the messenger. This is a great site, but it doesn’t replace a shop or necessary tools.

You can buy a product called "Sea Foam" and it is a complete package with instruction on how to use it. It works very well in cleaning the system and you only need to do it once a year or every 20K miles.

Thanks, Ron

Customer: replied 3 months ago.
Thanks Ron, but I need to clean the deposits that are there now. I am a change the spark plugs and oil level mechanic from the the 1960's. not a super mechanic but can follow directions.
Customer: replied 3 months ago.
Ron, I look Sea Foam up on the internet and it looks like it is for the crank case and is an STP competitor. This is a fuel injection problem common on the XC 90 family. Are you familiar with the problem?
Customer: replied 3 months ago.
I would like to switch to a phone call and and let you walk me through the cleaning process but first I need some confidence that you understand and can fix the problem. Your Sea Foam answer seems off track.
Customer: replied 3 months ago.
Can you give me a written overview of how to locate the fuel/air mixing box, the tools I would need to access the area and your recommendation for how to remove the deposits. I have watch from a distance at the garage and it does not look like the job is above my skill level.
Expert:  rpmdiag replied 3 months ago.

Sea Foam is for the entire intake system and will work to clean your system. If your system continually gets trashed up, then you have another issue going on that needs to be addressed. I would recommend having the fuel trims read on a scan tool for starters. And yes, I am VERY familiar with this issue. This cleaning is a maintenance job, but if you have an ongoing carbon buildup, then something else is wrong.

Thanks again, and please don't forget to rate me and keep this link in case you need me again later on.


Customer: replied 3 months ago.
Ron, Ok, I looked further into Sea Foam but my problem is not in the engine it is in the air fuel handling system. I have had the car for years and this issue comes up ever year or two. As I understand the system there is a chamber where the air and fuel come together and fuel is mixed over time a thin film of residue build us in fuel intake side of the chamber. My belief is that causes a disruption in the fuel air mixing. That might be wrong but the washing of the chamber alleviates the problem. If I knew how to do so I would clean the chamber every six months so that it is not an issue.
Expert:  sprinkles08 replied 3 months ago.

Hello and welcome to JustAnswer!

What you're referring to is the intake manifold. The intake manifold carries air to the cylinder head and the fuel injectors squirt fuel on the back sides of the intake valves. The intake, valves and combustion chambers will build carbon over time.

The product that the first expert mentioned can be used in the fuel, crankcase (I wouldn't) or it can be applied through the intake. You can use this product, throttle body cleaner or top end cleaner purchased from a shop or dealer. Either way the engine will need to be running and the product will be slowly introduced through the intake to draw it through. I'd prefer a spray rather than something like Sea Foam because it isn't easily controlled, if it goes in more quickly then it isn't going to have time to work and if you get carried away you could end up hydrolocking the engine.

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