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Discussion Starter · #1 ·
I have the 2007 Patriot with the VW 2.0 litre TDI deisel turbo, and have rebuilt the head and had the car running for a test drive before I did other works that has left me with a no start. This all came about initially from a glow plug breaking and damaging the turbo and an injector, which have both been repaired/replaced.

Still in limp mode during the test drive, but after a few other unrelated repairs I now don't have a start. Code error is the P2147 - Injector group - low voltage.

I do have ample fuel at the vacuum pump, and for those unfamiliar, this is the secondary pump attached to the engine block that delivers the fuel to the injectors, instead of a high pressure pump, as well as being the general vacuum pump for the vehicle. These VW's don't have a high pressure pump, only the tank pump, then the vacuum pump, which then delivers to the injectors where they each act as a 'pumpe duse' to obtain the proper injector pressure. As such, it is the injectors themselves that are the high pressure pumps.

The car is turning over without any start. First question is, can the vacuum pump be installed 180 degrees out. I figured this cant be the case as they are a simple rotary pump, but maybe I'm missing something, unlike a typical injector pump delivering fuel to the injectors at the correct timing, which needs to be set correctly at he pump. This fuel/injector pump can only go on one way, but in fact, the drive shaft can also be turned 180 degrees.

As mentioned, I've checked for fuel delivery at the vacuum pump from the fuel filter, which is abundant. So the tank pump is working fine, and there is no fuel blochages/air locks before the vacuum pump.

The low voltage reading may indicate that the solonoids on each injector aren't firing as they should. The wiring harness on these vehicles sits under the rocker cover, leaving them to the upper engine oil etc, but this is the design and prior to the turbo damage, the harness showed no issues. Its not an odeal design, but is what it is. I've cleaned all terminals.

Air lock inside the engine or vacuum pump ? I can't see how this type of fuel/vacuum pump can have an air lock, so it could only be after the pump within the fuel passages/tunnels within the head that deliver fuel to the injectors. Not likely I think, but unsure.

I suspect then that it is the low voltage code error preventing the start, which probably requires electrical testing at the injectors. Don't have a multimetre or am an expert in this field, but could work it out if required.

Lastly, it could be the injectors or valves themselves, as I did have the timing incorrect for a very short period when trying to start after the secondary works I performed. But timimg now is correct. But I won't remove the injectors or head again before I try to resolve by other means.

Any ideas most welcome ?
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