Are Fuel Pump Failures Sidelining Volkswagen's Diesel Engines?

The diesel-powered Volkswagen Jetta, Golf, Passat, Beetle and Audi A3 have been amongst the most popular diesel vehicles on the market (partially because they're most of the market), with dealerships reporting constant high demand -– TDIs are about 90 percent of sales in the case of the Jetta Sport Wagon.

But there's a problem that's affected a small number of TDIs that could just be the tip of the iceberg. According to The Smoking Tire, some owners have had their VW or Audi TDIs stall and unable to be revived because of the fuel pump failing.

An investigation from the NHTSA, opened in February 2011 affecting 2009-2010 Golf and Jetta TDIs, reported 160 incidents where owners had stalling incidents. But in the same report, VW said it told dealerships that "fuel system damage incurred by use of fuel not complying to ASTM-D-975 Grade 2 S15 (B5 or less biodiesel content) standards will not be covered under warranty." Furthermore, VW said it had 121 reports of customers admitting mis-fueling their cars, which probably means people putting in regular unleaded instead of diesel.

That is an ongoing investigation into 2010 and 2011 Golf and Jetta TDIs, and TDI Club has a list of fuel pump failures by state. As of yesterday, there are 11 owners of 2012s reporting failures -– that model year is not covered by the investigation. There are also reports of owners experiencing 2 fuel pump failures.

Owners of Passat TDIs are also reporting stalling issues, and the NHTSA does not currently have any investigation open into Passats or any 2012 TDIs. The issue may really be with the high pressure fuel pump not being capable of dealing with diesel that's been contaminated by gasoline by fuel stations and tankers. TDI customers, particularly the diehards, know better than to go filling their cars up with regular unleaded, but what they can't control is diesel being improperly handled. And VW doesn't want to pay for repairs for something that looks like an error made by the customer.

Worse may be that customers have been unable to drive their cars because of lengthy waits for parts, some reporting that their cars were out of commission for more than six weeks.

"Volkswagen considers the safety and satisfaction of our customers as a top priority," Darryll Harrison, VW manager of west coast communications, said yesterday. "In May 2010, Volkswagen Group issued a technical service bulletin to address reported issues with TDI fuel pumps and continues to fully comply with NHTSA's inquiry related to this matter. In reviewing our parts inventory, we found that there is sufficient stock of the part for both Volkswagen and Audi brands."

Harrison said he couldn't comment on issues of specific customers. But he said even a trace of gasoline in a diesel system could spell doom for the fuel pump.

"Contaminated diesel fuel can cause issues throughout the system," he said. "In some cases, even small amounts of gas mixed with diesel can interrupt the function of several parts within the fuel system, including the fuel pump, and cause it to fail."

It could be that the parts supplier, in this case Bosch, needs to make a more durable high pressure fuel pump. Is this a reason to avoid a TDI? I don't think so, but it is a reason you should make sure never to fill your car with gasoline and have some evidence to back it up in case your car stops working and VW doesn't want to pay for repairs.

Are there any TDI owners out there experiencing problems with stalling? What are some ways drivers can avoid contaminated diesel? Americans are increasingly responding to this new generation of diesel-powered cars, and they are great alternatives to hybrids. A growing problem like this is the last thing diesel's reputation in this country needs.

Photo credit Volkswagen