Polo SDI Diesel Knock

[baconboy]

Hi People

I need some help with my Polo SDI please!
Its been running fine then I took it for M.O.T the other day it passed no problems and went through the smoke test fine.
The tester comented that the engine was noisy and I should check the timing.
I thought whats he chatting about the car is lovely and quiet and runs great.
I left the test station and heard horrendous diesel knock I mean really loud. I suspect they reved the **** out of my car on the smoke test and something hasnt liked it.
I took it back to my workshop and fitted all the timing tools, As I thought the timing was spot on as I only put a belt on it in Nov 08.
I then feed the fuel pump direct from a jerry can with a inline filter to eliminate any damaged or squased fuel lines or shity fuel filter, no difference.
I left the car in my workshop over night then started it up the next day it was fine no noise i drove it for about 2 minutes then it started and now the diesel knock is there all the time.
Im starting to suspect the fuel pump is at fault maybe a fuel metering valve or something else inside the pump.
I have also tried forte fuel cleaner, the inlet manifold has been cleaned and all of the egr system has been checked and is ok.

Has any one got any suggestions or come across heavy diesel knock on the VW 1.9 Sdi Engine?


Any Help would be appreciated

[dave4563]

I don't have an Sdi, but have a 98 1.9 D, which is making all manner of creaking and knocking noises, mainly when changing gear at low speeds and moving along in low speed traffic. This is worrying me, and the knocking noise seem to be coming from front to back of the car.Iv already spent large amounts of money on suspension bushes so this knocking problem will have to wait a while. Let me know if you have any luck with yours, so any expertise is thoroughly appreciated!

[heliosuk]

I think you need to start with basics here. First carry out a leak off test and check that each injector is within spec and then do a compression test.

Let us know the results and can take it from there.

[baconboy]

The injectors are fine thanks and the needle lift sensor on no 3 is working

[heliosuk]

Have you done a leak off test? Sensor might be fine but have you considered the possibility of a tolerance stack?