Knock in engine

[adspynappels]

Hi all

Got a salvage Q7 that had so little damage that I was fixing myself and is now ready to get back on the road.

It was a non runner and sold as such with no indication of the problem.

After doing some diagnostics myself I got it pinned down to cylinder 1 injector over fueling and passing all fuel rail pressure straight to the cylinder. Hence not starting, I blocked the fuel line to injector 1 and it started on 5 cylinders all be it a rough idle.

The injector has now been replaced and coded in but the car has developed a knock. I have read all about injector knock so I was wondering if the rail now being back at the correct pressure has caused one of the other injectors to have issues? Or could the problem be something else?

Just to give a bit of back story also, when I pulled the old injector out it was badly tarred up. There was no copper washer at the end of the injector. My worry is that the copper washer broke into bits and went into the cylinder but because I could not see any remnants of a copper washer I don't think it was there before. I believe someone has been playing about before I touched the engine, as the old injector code did not match what was on the car computer.

Out of interest I also looked at the other injectors to see if they also didn't match the coding, and number 3 was not coded correctly. Perhaps it wishful thinking but that's where I think the knocking is coming from.

Any suggestion on how to know where the knock is coming from or what I could do to whittle the problem down?

It is a 2011 3.0 V6 diesel. Engine code is Cjga.

Thanks in advance.

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[Crasher]

The washer gets vaporised and blown out the vent, do the seals/seats on the rest.

[adspynappels]

The washer gets vaporised and blown out the vent, do the seals/seats on the rest.

Thanks Crasher. Will give it a try and report back.

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[adspynappels]

Done the copper washer on the rest and looks like someone has been there before me on one bank of injectors. The bad ones being number 1 and 2 so running better now. Still a slight knock but I think if the engine has new fresh oil and full set of filters it will help alleviate that.

I replaced in total 2 injectors, is it possible to get these old ones reconditioned in case any more fail in the near future? Anyone any contacts who would be good for this?

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