So in the order from The Dub Doctor I got a new set of injector nozzles to replace the ones I am sure are all gummed up. Before putting in the new nozzles I decided to take the injectors to a diesel shop up in Loveland to get the pop-off pressures tested. The pop-off pressure is the amount of fuel pressure the injector holds until the mechanical resistance from two springs in the injector is overcome and the fuel shoots through the holes in the nozzle into the cylinder. Take a look at this image of injectors to get a better idea of what happens.
The injector is a crucial part of the engine, an accurate pop-off pressure and a specific spray pattern are required to ensure the fuel fills the combustion chamber and burns evenly. For those who have been reading, if the fuel is sprayed into the chamber haphazardly it will burn incompletely causing smoke and carbon deposits. Well, about 10 minutes into the ~30 minute testing procedure I got called to the shop to see the injectors. Normally when an injector is tested on a manual tester the fuel pops-off a number of times and chatters like the video below, well three of the four injectors were so gummed up there was no chatter, just a dribble out of the nozzles. In addition to the gummed up injector internals, all the nozzles were spraying in random directions, even up! These injectors are really, really bad; I don’t even know how the car was running. The Doctor thinks they can be cleaned, so tomorrow I get to pack them up with the new nozzles and ship them off to Ohio.
In other news the engine shop should be done rebuilding the engine and tomorrow or Friday it will go back to the VW shop to be put back in the car. It should take a week or so to get everything back together. I just hope the injectors get back so it isn’t waiting too long. Also, the messed up injectors make me worry the injector pump is gummed up…lets hope that isn’t the case.
Check out this page for more on VW TDI VE and PD injectors : http://www.myturbodiesel.com/1000q_how_to/multi/TDInozzleFAQ.htm