Terrible Engine Knock

GMC85 · Jul 22, 2015

Okay so I have been getting this knock for a little over a month now and it seems to be getting worse by the day.
When I touch the accelerator at all it sounds like Bren gun firing under the bonnet and the is a cloud of black smoke that would lose a Bond villain.

So far I have replaced all 4 injectors, blanked off the EGR, replaced the in-line fuel pump and the fuel filter, replaced the MAF filter, replaced the fuel pressure sensor, replaced the camshaft sensor. I regularly run diesel rhino through it and only use BP ultimate diesel.

What's left to do apart from get my 12 bore out and take the car into a field?

It happens more the more I put my foot down, but it still happens when I'm nursing it in 5th going 25mph.

It starts fine, no revs dropping, no smoke on start-up. No warning lights.

2003 TD4 (stupid designed one with the fuel pump and filter under the wheel arch)

Littelwill · Jul 22, 2015

Right soooo was it doing this before you changed your injectors etc or has it started since?

GMC85 · Jul 22, 2015

Littelwill said:
Right soooo was it doing this before you changed your injectors etc or has it started since?

Yes it started about 6 weeks ago. I changed the injectors 3 weeks ago and it made zero difference. When I changed the fuel filter 2 weeks ago it helped for about 1 day then it was back. So definitely a fuelling issue.

Littelwill · Jul 22, 2015

Ok... Im not sure if its going to help but here is a tale of woe....

In the pursuit to rid my P38 of an idle vibration I had my injection pump timing checked and then checked again (in total we checked it about 8 times) in doing this I had to remove the high pressure fuel lines (metal ones) that run to the injectors... after checking the timing and putting it all back together I went to start it and KNOCK KNOCK KNOCK KNOCK!!! I turned it off and thought bottom end bearing or something. Anyway long story short it was a MAJOR air lock on injector 5 that was the cause. I had to crack all the injectors off and one by one then nip them shut once a good mist of fuel came out. my advice would be WITH HELP start your freelander and crack all of the injectors off one by one. The injector with the air lock will be very obvious and your knock will stop. With the engine still going close all the other injectors and bleed the hell out of the one with air in it.

This is what I did and it worked. Be warned it took a while to get all the air out. you'll need a helper to turn the engine on and off if things get messy.

Hope that helps you

Jason101 · Jul 22, 2015

Is it underpowered or just making a noise?

GMC85 · Jul 22, 2015

Jason101 said:
Is it underpowered or just making a noise?

It's got the power but revving it causing the knocking which causes it to chug along. So I don't really put the foot down. There is zero issue in idle.

GMC85 · Jul 22, 2015

Littelwill said:
Ok... Im not sure if its going to help but here is a tale of woe....

In the pursuit to rid my P38 of an idle vibration I had my injection pump timing checked and then checked again (in total we checked it about 8 times) in doing this I had to remove the high pressure fuel lines (metal ones) that run to the injectors... after checking the timing and putting it all back together I went to start it and KNOCK KNOCK KNOCK KNOCK!!! I turned it off and thought bottom end bearing or something. Anyway long story short it was a MAJOR air lock on injector 5 that was the cause. I had to crack all the injectors off and one by one then nip them shut once a good mist of fuel came out. my advice would be WITH HELP start your freelander and crack all of the injectors off one by one. The injector with the air lock will be very obvious and your knock will stop. With the engine still going close all the other injectors and bleed the hell out of the one with air in it.

This is what I did and it worked. Be warned it took a while to get all the air out. you'll need a helper to turn the engine on and off if things get messy.

Hope that helps you

Was yours knocking in idle. Mine isn't. Don't know if that makes a difference.

englishbullterrier · Jul 22, 2015

Have you considered little end (or big end) bearings at all ?

Cabbie · Jul 22, 2015

Is the injector pump timing too far retarded?

clarkkent · Jul 23, 2015

Could be crankcase breather filter but possibly turbo

Jason101 · Jul 23, 2015

Have you changed the fuel pump! And check the wiring to the Injectors. Might be a faulty injector.

Terrible Engine Knock

GMC85

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Littelwill

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GMC85

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Littelwill

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Jason101

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GMC85

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GMC85

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englishbullterrier

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Cabbie

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clarkkent

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Jason101

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