Forums » Ask a Question

Use this forum to post your questions to our experts – you need to be logged on to do it (you can register here ), then scroll down to the bottom of this page and click the blue Post Thread words

If you can help answer the question, feel free to post a reply – you need to be logged on to do it (you can register here ), then hit the reply button on the thread.

 

To go back to the experts page click here>>

AuthorMessage
geoffrey
geoffrey

Posted: Wed Jul 27, 2016 4:19pm

Post Subject: Misfire on a Lister/Petter LPWS4

Hi Tony, About 2 weeks ago, quite without warning the engine a LPWS4 started to make a knocking noise and at the same time the normally clean exhaust was a bit smoky ( black). It seemed like a misfire and as the engine continued to run and I was near to my mooring, I carried on slowly. Then, after maybe a minute or two, it disappeared and ran normally. On reaching my mooring, I let it tick over for a few minutes, then while in neutral increased the revs to about 2000 rpm and again, all seemed fine. Then, after setting off for a 2 week cruise, on the second day, we experienced the same symptoms for maybe 5 or so seconds. For the rest of the 10 days averaging 5 hours a day, the engine has performed perfectly. I have always serviced the engine to schedule and although it is 1996 vintage, has only done 2500 hours. I keep the fuel tank full over winter and dose it with Fuel Set for the last 3 or 4 years and now Marine 16. On about the 4th day, a fuel filter change was due, which I did and the fuel which ran out of the old filter looked pristine. Could this be be the precursor to an imminent failure? I am wondering if somehow there was a bubble of air in one of the injector feeds which then bled through? If so, how did it get in and could it happen again? I have looked for signs of a cracked pipe etc. but all seems OK and given the searching nature of diesel fuel would expect to see evidence of a leak. Any thoughts please, if only to put my mind at rest?

Tony-B
Tony-B

Posted: Wed Jul 27, 2016 5:14pm

Post Subject: Misfire on a Lister/Petter LPWS4

I doubt that it was air but remember that when the engine is running part of the fuel system is potentially under suction so could suck air through a poor joint while not allowing diesel to leak. Air is far thinner than diesel. In any case the engine is nominally self bleeding so should have got rid of the air long before it got into the high pressure pipes. Two things occur to me. The most likely is that an injector stuck. My approach would be to start adding injector cleaner to the fuel and see how it goes. If that does not sort it then it may need the injectors servicing. The second thing is that I think this engine uses self adjusting hydraulic valve lifters. Please check in the manual. If this is so then one may have collapsed for a short while. Short of stripping the engine I think the best thing to do would be to regularly use a flushing ADDITIVE each time you change the engine oil. This can be purchased from motor factors. It is added to the oil and the engaging run up to temperature for a while so the additive can "attack" any deposits throughout the engine. Then the oil is drained and refilled in the usual way. On the basis of the information given I do not think this is a precursor to a major failure.

geoffrey
geoffrey

Posted: Wed Jul 27, 2016 6:48pm

Post Subject: Misfire on a Lister/Petter LPWS4

Thanks for the advice Tony, I will try the injector cleaner in the fuel first and see what happens. You are right about the lifters being hydraulic and I remember being told by the Lister people at Dursley back in 1996 when we bought the engine that this is the main reason to ensure oil change intervals are adhered to (every 100 hours). The oil only seems slightly darkened when drained unlike my diesel engined car which gets black quite soon after changing. Cheers.

Most Read

Newsletter Sign Up

Canal Boat monthly newsletter
Sign up to receive our regular email newsletter

Our Privacy Policy

Like us on Facebook



Follow us on Twitter

Cache: Disabled for this object  Total Queries: 43.  Total Objects: 162.  Total Unserialized: 3. Total Runtime: 0.42 seconds.