Ford's answers to the NHTSA 6.7 Investigation
There was a request for a link to Ford's answer's to the NHTSA investigation posted on a previous thread, since closed. Here is the link: Ford's NHTSA Answers to the 6.7 investigation This PDF i...
Forum Discussion
BenK wrote:
Ah...don't forget that the piezo valve being slammed shut by it's own coil springs are
assisted by back flow combustion chamber PSI via diesel fuel being burned !
{edit}....another Ah Ha !!!!
Always wondered, but haven't had the time nor inclination to noodle it
out on how those injector orifices keep from carbonizing/choking shut
Must have residual fuel being pushed back by the combustion process that
then is the 'plug' that keeps it clean enough for the next million cycles...
Most of Bosch's nozzles were built, somehow, with some sort of Delaval nozzle effect, which created a form of cavitation that was self cleaning of carbon deposits from fuel being burnt by the good old Italian tune up method... in other words, red light racing in city traffic, 3, 4 or 5 good romps, or a good stomping of the accelerater going through the gears getting on the freeway was enough to clean the nozzles up... it was as clear as looking in the rear view mirror and watching the soot and smoke disappear in blvd traffic, the 2nd or 3rd romp usually did it on my 2002 Vw TDI. Don't know how it works at 1600, 1800 or 2000 bar HPFP pressures.
Will let you guys know how my 2012 Passat TDI with solenoid nozzles and newest version of CP4 family of pump holds up. Bosch has gone from VW part number ending in 155 A to version 155 E for the Passat in 2012... might be dirtier, lower pressure, but they manage to clean it up on the back end with DEF fluid in a sedan. BTW... the A version is on 2009 -2012 VW products with piezo injection, Golf, Jetta and Sportswagent like the Ford 6.7. Like some of the smart folks around here, I am holding on to my old technology 2002 jetta TDI with only 150k miles on it, as a back up.
