ST?ID=105165
TDI CR from hell, well, all of them are from hell, but this one, a bit more hell. Long and short of it, it was suspect that the fuel injectors were leaking (dumping) fuel. When we first got involved with the car, extended cranking and the engine would fire. Watching fuel rail pressure while cranking, it would slow ramp up and once it hit 50 BAR would fire.
Some tinkering was done with the car and then it became a no fire issue, and fuel rail pressure while cranking wasn't going up at all. Dana tossed onto the table that the injectors might be leaking. Two issues in trying to test this... there was no rail pressure while cranking, so there was nothing to bleed away. And then it seems that by design, the TDI CR will dump rail pressure when the engine is shut off anyway. Figure it is a diesel, if you shut the engine off, you don't want it to "diesel", so the N276 could be triggered, thus any rail pressure is bleed out instantly so there is no fuel supply to an diesel you are trying to shut off.
So how to test if the fuel injectors are leaking?
Thanks to Steve K. of from Rio Linda, CA for doing the legwork and testing out my "lets cap off the rail" plan.
Some quick and dirty hacking of course from some scrap parts from another failed TDI CR engine. In short, remove the metal lines from the fuel rail, put on cap nuts so now the fuel rail becomes a sealed unit. Crank the engine while watching rail pressure and in this case, it jumped up to 100BAR pretty quickly, thus proving the injectors were dumping.
Had the system still not built up pressure, then the N276 could be leaking or the N290 just isn't able to make pressure in the first place.
Before anyone ask, no glitter has been found. We don't know why the injectors failed in the way that they did.
TDI CR from hell, well, all of them are from hell, but this one, a bit more hell. Long and short of it, it was suspect that the fuel injectors were leaking (dumping) fuel. When we first got involved with the car, extended cranking and the engine would fire. Watching fuel rail pressure while cranking, it would slow ramp up and once it hit 50 BAR would fire.
Some tinkering was done with the car and then it became a no fire issue, and fuel rail pressure while cranking wasn't going up at all. Dana tossed onto the table that the injectors might be leaking. Two issues in trying to test this... there was no rail pressure while cranking, so there was nothing to bleed away. And then it seems that by design, the TDI CR will dump rail pressure when the engine is shut off anyway. Figure it is a diesel, if you shut the engine off, you don't want it to "diesel", so the N276 could be triggered, thus any rail pressure is bleed out instantly so there is no fuel supply to an diesel you are trying to shut off.
So how to test if the fuel injectors are leaking?
Thanks to Steve K. of from Rio Linda, CA for doing the legwork and testing out my "lets cap off the rail" plan.
Some quick and dirty hacking of course from some scrap parts from another failed TDI CR engine. In short, remove the metal lines from the fuel rail, put on cap nuts so now the fuel rail becomes a sealed unit. Crank the engine while watching rail pressure and in this case, it jumped up to 100BAR pretty quickly, thus proving the injectors were dumping.
Had the system still not built up pressure, then the N276 could be leaking or the N290 just isn't able to make pressure in the first place.
Before anyone ask, no glitter has been found. We don't know why the injectors failed in the way that they did.
