VW started selling diesel engines with unit injectors almost 15 years ago in Europe and the USA. VW invested heavily in the technology, but it just couldn't meet the emissions standards at low RPM's. VW stopped producing engines with unit injectors around 2007, so there are a lot of VW TDI's on the road with these injectors. Sometimes the injectors get gummed up and stop working all together, but mostly, one injector gives either too much or not enough fuel, compared to the other injectors. Regardless of what the problem is with your unit injector, we can rebuild them for $150.

You may have never heard of BIP testing or pop testing, but we have. The top picture on the right shows a VW TDI unit injector. The middle right picture shows the BIP (Beginning of Injection Period) and the Pop Pressure Tester for unit injectors. The lower right picture shows the unit injector testing machine where the injectors are flow tested. The unit injector was VW's first attempt at electonically controlled injectors, so special testing equipment is needed to rebuild them.