#Gdi

Hi Sajeev & Steve,

“You have not covered extensively the problems encountered by GDI engines, especially Mitsubishi Dion (the engine is 4G63). As the revs go beyond the 2000 rpm, the ‘check engine’ light comes on, then eventually the engine — if forced — cuts off. After a few minutes, the engine can start but it does not take long before it repeats. I was told by a mechanic to buy a new pressure pump. This was fitted but the problem has not gone away. Please help!”

Ummm… we think your mechanic needs to keep away from Runaround Sue.

TUV Nord, a safety testing and certification agency, has issued a report commissioned by an environmental group that says that modern engines that use gasoline direct injection (GDI) of fuel emit more small particles in their exhausts than modern diesel engines. Particulates raise concerns over possibly causing cancer. GDI has proliferated as a means of increasing power, improving fuel efficiency and lowering CO2 emmissions but TUV Nord says that GDI engines put out 1,000 times more harmful particles than traditional gasoline engines and 10 times more than the latest diesels. The study is based on a sample size of three cars, a Ford Focus with a 1 liter EcoBoost engine, a Renault Megane with a 1.2 liter Energy TCe, and a Hyundai i40 with a 1.6 liter GDI engine.

“The cost of a filter to eliminate particle emissions from GDI cars is low (around EUR50 [~$68 US]), with no loss in fuel efficiency and a big societal benefit. Despite this, carmakers are delaying fitting filters on GDI cars,” the Transport & Environment advocacy group based in Brussels said in a summary of the report.

Zack writes:

Hi Sajeev,

I’ve been following a series of discussion on a MK3 Ford Focus forum; in particular I’ve been following the technical discussion about how to squeeze more power from the MK3’s new 2.0 GDI motor. Of course, this involves talk of CAIs, Cat-deletes (inadvisable), and free flow exhaust. One of the more curious things to emerge is…

Kurt asks:

I’ve heard from maintenance shops and oil additive producers that DI engines, especially Audi and BMW, have severe problems with carbon buildup in their valve systems. Might be good to chat about this and also poll readers to see if other vehicles have the same issue. Thank you.

“Ask an Engineer” is hosted by Andrew Bell, a mechanical engineer and car enthusiast. Andrew has his MASc in Mechanical Engineering from the University of Toronto, and has worked on Formula SAE teams, as well as alternative fuel technologies in Denmark and Canada. Andrew’s column will explore engineering topics in the most accessible manner possible.