GQ RD28 engine knocking - any ideas?

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Joined: February 9th, 2019, 7:52 pm

GQ RD28 engine knocking - any ideas?

Unread post by Davez5 » February 10th, 2019, 7:06 am

Have a GQ RD28. Was running fine but had a leak from injector pump. Had injector pump replaced with another second hand one and now it has a knocking noise coming from engine and smells really fuelly. Have checked all timing Marks and they're lined up. Any ideas?

Peter Aawen
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Joined: June 17th, 2005, 8:01 pm

Re: GQ RD28 engine knocking - any ideas?

Unread post by Peter Aawen » February 10th, 2019, 9:20 am

Hi Davez, welcome to the Forum.

Sounds an awful lot like you've got Injector Knock going on there now! Basically, that means that for some reason, one injector isn't working/atomising the fuel properly so it's not firing on that cylinder (hence the knock) & the unburnt fuel is being pumped out the exhaust (that's the smell!) Could be happening for all sorts of reasons, but you REALLY don't want to run it for too long like that or you risk blowing that piston &/or valves!! You should be able to quickly identify which injector is knocking by using a mechanic's stethoscope or a long handled screw driver - hold the handle of the screw driver firmly onto one ear & put the blade onto each injector in turn & listen for the knock as the engine runs/idles, the knocking injector should be obvious!

**** WARNING **** Home Spanner-spinners BEWARE! You REALLY need to be careful if you are going to play with diesel injection systems yourself! Getting sprayed on unprotected skin or in an eye etc with injection pressure diesel spray can very quickly be fatal - if you gets hit somewhere on a limb, ie on the hand or arm, & the spray pierces the skin or gets into your bloodstream via an existing cut, often the only way to save your life will be to amputate the entire limb, and even then if that's not done quickly enough after being sprayed then goodnight! The pressure the diesel gets pumped out of the I/P at hitting you on unprotected skin is bad enough, but the very fine atomised spray coming out of an injector is even worse!! It can cut right thru skin! And 'light clothing' does NOT make for protected skin! So it is usually very much the smart thing to do by leaving working on any diesel injection system downstream of the injection pump to someone with the right knowledge, skills, workplace, protective gear, equipment, and experience!
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

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