Injection pump timing and diesel knock.

Steviecops · May 1, 2013

If an injection pump is advanced a tad too much, resulting in slight diesel knock, can engine damage result? My engine runs fine and doesn't smoke, but I'm not sure if I've got a bit of diesel knock or not. It's not a particularly loud noise, ie, it's more of a tick than a heavy thump, but listening with a long screw driver, it is most audible when it's placed on the injection pump, injection pipes and injectors. Tappets aren't noisy and neither is the vacuum pump. Head gasket isn't blowing anywhere and I've recently changed the mainfold gasket.

timtheenchanteruk · May 1, 2013

AFAIK its not an issue as long as its not excessive (ie preignition) older non direct injection engines had deisel knock as standard due to the design, and they used to go on forever.

hope not anyway, cos mine does it a touch too, but theres no info that ive found on the net to say its a big problem.

jamesmartin · May 1, 2013

Steviecops said:
If an injection pump is advanced a tad too much, resulting in slight diesel knock, can engine damage result? My engine runs fine and doesn't smoke, but I'm not sure if I've got a bit of diesel knock or not. It's not a particularly loud noise, ie, it's more of a tick than a heavy thump, but listening with a long screw driver, it is most audible when it's placed on the injection pump, injection pipes and injectors. Tappets aren't noisy and neither is the vacuum pump. Head gasket isn't blowing anywhere and I've recently changed the mainfold gasket.

diesel knock wouldnt be heard in the injection pump timing has no effect on the pump,your noise could be a good few things,diesel knock could be adjusted away by retarding pump slightly ,but before doing that get a second opinion

Steviecops · May 1, 2013

Thanks. Next question, then, is there anyone in the Colchester area willing to have a listen? Or would posting a short video be of any use?

Steviecops · May 3, 2013

Any ideas?

78512997-C95A-487F-A401-A5BAFABFBAC3-10145-00000DC5E5AEA38F_zpsd84cb301.mp4

Turboman · May 3, 2013

Steviecops said:
Any ideas?

If it runs ok, performance and fuel econ. are what you would expect I would leave well alone.

Steviecops · May 4, 2013

Thanks, I will do.

ferretboy · May 4, 2013

May be worth having injectors tested ! If they over fuel this will cause a compression type nocking ! Usualy runs a bit smokey !!

Steviecops · May 5, 2013

Thought I'd already posted this short video, but it hadn't worked.

lyron · May 7, 2013

sounds about right to me.

best to leave well alone.

defenderdan86 · May 7, 2013

the pump sounds a tad noisy, try opening the fuel bleed screw slightly whilst its running and if the noise gets quieter close bleed screw turn engine off, undo the slot headed screw on the lift pump take the cap off n clean the little gauze, if its blocked it will restrict the fuel going to the pump slightly n make it a tad louder than it should be.

defenderdan86 · May 7, 2013

defenderdan86 said:
the pump sounds a tad noisy, try opening the fuel bleed screw slightly whilst its running and if the noise gets quieter close bleed screw turn engine off, undo the slot headed screw on the lift pump take the cap off n clean the little gauze, if its blocked it will restrict the fuel going to the pump slightly n make it a tad louder than it should be.

just to add a failing lift pump would also make the injection pump noisy as its being starved of fuel.

Steviecops · May 7, 2013

The lift pump is pretty new. Fitted it around January/February time. I have had to clean the gauze filter in it a few times. Seems odd that they should stick a gauze filter in the delphi lift pumps before the fuel filter. Just wondering if I could do away with it and let the fuel filter do its job?

defenderdan86 · May 8, 2013

Steviecops said:
The lift pump is pretty new. Fitted it around January/February time. I have had to clean the gauze filter in it a few times. Seems odd that they should stick a gauze filter in the delphi lift pumps before the fuel filter. Just wondering if I could do away with it and let the fuel filter do its job?

Im not quite sure about that, if uve had to clean it a few times previously then with no gauze that stuff would end up in ur injectors which wouldnt be too good. has the fuel filter been done recently?

Steviecops · May 8, 2013

I would have thought the fuel filter would stop any crap getting into the injectors? I think it's only the Delphi pumps that have the gauze filter, so anyone running a different lift pump won't have the gauze filter anyway. I change the fuel filter regularly, but its probably due for a new one.

defenderdan86 · May 8, 2013

Steviecops said:
I would have thought the fuel filter would stop any crap getting into the injectors? I think it's only the Delphi pumps that have the gauze filter, so anyone running a different lift pump won't have the gauze filter anyway. I change the fuel filter regularly, but its probably due for a new one.

oo i did not know this, mayb try pullin it out n see if it makes a difference. somone may come along and shout at me for suggesting such things

Steviecops · May 8, 2013

I've searched for an answer and can't find one. With the sedimentor and then this little gauze filter, the main fuel filter is almost redundant. It's so easily clogged, I might whip it out and see what happens.

defenderdan86 · May 9, 2013

Steviecops said:
I've searched for an answer and can't find one. With the sedimentor and then this little gauze filter, the main fuel filter is almost redundant. It's so easily clogged, I might whip it out and see what happens.

sweet, come back n let us know if it makes a difference.

Steviecops · May 11, 2013

Well the gauze filter was cover in crap, so gave it a good clean and put it back in. Injection pump a lot quieter now. I was going to leave the filter out, but bottled out!

. Seeing the crap that it collects, if even a little bit of that made it through the main fuel filter it would clog the injectors in no time. I'll have to do a bit more research before deciding whether to take it out or not. It's a pain having to keep cleaning it out, but worth making it weekly maintenance to keep things running sweet.

biolandy · May 14, 2013

I would check your fuel quality if your still using bio-something is wrong somewhere for the gauze to block so quickly.I only clean my gauze once a year on my home brew.
I would not leave the filter out,nothing else in the fuel line filters to 5 micron.

Injection pump timing and diesel knock.

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