jmule

I have been researching the carbon build up issues of direct injection for a while now. All manufacturers have had this problem. I monitored my air intake volume today and calculated airflow at various rpms. I determined that my engine has a reduced VE, between 2500-4000. The airflow is about 75% of the calculated value. In addition, I also monitored the LTFT and it is definitely constantly trying to compensate for reduced air. The issue has gotten bad enough that it is now occasionally storing code p2178 (system too rich off idle). I plan on removing the intake manifold, cleaning the intake ports and then installing a 90/10 water/meth injection system of my own design.

All manufacturers that use direct injection have this issue. Some newer designs are using an extra injector into the intake manifold. There are some 5th injector kits available, but they are very expensive. I do think the water/meth will work very well. I plan on running a 50,000 mile check, after installing it to see how well it keeps the ports clean.

DrLoch

DI does come with it's own set of problems, but, my feeling is that the 5th injector is one solution and be the less expensive to implement by the manufacture.

jmule

I like the way it works for the most part. You are getting the most out of every drop of fuel. The fuel trims are really fast when the system is working properly. Taking off the intake is not at all a hard job. I also plan to get the injectors cleaned and flow tested at injectorRX in Texas. They claim to have as fast as a 24hr turn around time on them. ..Just cause I will be in there.

87ninefiveone

Intake build up is a huge problem on VWs and Audis with the 2.0T engine as well. There's a lot of people with MKV GTIs who swear on intake removal and cleaning every 10-20k miles because of the issue. Seafoam fed into the intake is typically recommended but makes me a bit nervous since you could potentially dislodge large chunks of material or poison you cat if large amounts of residue are present. From everything I've read occasional manual cleaning is the way to go.