|
martin
Veteran
Date registered: Apr 2006
Location: Del Mar, CA Isles of Scilly, UK
Vehicle(s): 99 G500 95 E300D 95 R1100GS 06 K1200R
Posts: 297
| injector knock
My '85 300GD has developed a noticable knocking noise in the fuel delivery/injection system that I have narrowed down to the #5 injector by listening to the injector lines with a screwdiver stuck to my ear! At first I thought it might be a suspect tankful of cheap diesel since the engine was also pinking, but I have since refilled the tank with "good" diesel and both the pinking and knocking are present. I did the Lubromoly treatment by running a can through the injector pump and then dumping a can into the tank when the tank was near empty and I also changed both the fuel filters just in case there was some crud lodged in them. There wasn't a noticable drop in power (sort of an oxymoron with a 300GD!), so I don't think a clogged filter is the culprit.
Is this a sign of the #5 injector starting to fail or could the fuel spray pattern be deteriorating? Also, could it be a failure in the precombustion chamber?
Many thanks in advance. |
|
| |
|
Inkblotz
Expert
Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3186
| Re: injector knock
Does it happen all the time or just at start up? If just @ start up it could be a bad glow plug for that cylinder.
If it happens while driving. Have you done the crack open the injection nuts test? Open each nut attached to the top of the injecter one at a time and see if there is a marked difference in the way it idles. If there is little change on that #5 injecter than you can be fairly confident that that injector is @ fault. Replace or have rebuilt that injector. It is probably dribbling fuel instead of spraying.
Mark |
|
| |
|
martin
Veteran
Date registered: Apr 2006
Location: Del Mar, CA Isles of Scilly, UK
Vehicle(s): 99 G500 95 E300D 95 R1100GS 06 K1200R
Posts: 297
| Re: injector knock
Inkblotz -
Does it happen all the time or just at start up? If just @ start up it could be a bad glow plug for that cylinder.
Thanks for the tip Mark. It knocks all the time ... start-up and whilst running. I'll try the "crack" method tonight and see what happens.
Martin |
|
| |
|
dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: injector knock
Ah Hah, the old screwdriver in the ear ploy. Did the lubromoly smooth out the sound and make a change? I would bet the #5 injector is going south and rebuilding it might solve the problem. Until we meet again and the case is solv ed.
-Dai |
|
| |
|
martin
Veteran
Date registered: Apr 2006
Location: Del Mar, CA Isles of Scilly, UK
Vehicle(s): 99 G500 95 E300D 95 R1100GS 06 K1200R
Posts: 297
| RE: injector knock
Thanks for the input. The fault was a partially clogged injector. I replaced all 5 injectors with rebuilt Bosch units and the engine is very happy. The knocking and pinking are gone .... back to the smooth musical trance of a diesel!
Although my odometer only shows 14.5K miles, I suspect it is really 114.5K + miles (the odo works intermittanty). Since I don't know have an accurate history of the engine maintenance, I guess 100K miles could be the lifespan of an original injector. The rebuilt injectors where less that $45/each, so it wasn't too expensive a repair.
Dai, I did the Lubromoly treatment because I am a firm believer in the benefits of Lubromoly Diesel Purge. I have used this product for years in various diesels that I have owned with positive results. This time, however, the injector couldn't be cured with Lubromoly treatment. |
|
| |
|
T.Schuhe
Elite Veteran
Date registered: Apr 2006
Location: Olympia, Washington State, USA
Vehicle(s): 460 1985 LWB 300GD five speed
Posts: 711
| RE: injector knock
As Chief Inspector Dai says, "...this case is sol ved." Just ask my mim key.
ts |
|
| |
|
dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: injector knock
Martin, excellent news. I too think Lubromoly Purge is great stuff. I also think that Redline Diesel Fuel Catylist is a product to run a little of all the time. It lubricates those high precision parts and makes them live a long long time.
Thomas, do you have a leesanse for that???
-Pie Crust |
|
| |
