VALVE ADJUST ~ this is _ALWAYS_ the first step .
As long as there's crud in the intake fuel screen , I'd be adding 3Oz. of STARTRON and nothing else (The salesman will insist his crap is better , it's NOT) .
Water etches the IP but it blows the tips out of the injector nozzles causing right running and black smoking .
It is best to supervise your son adjusting the valves as it's easy to damage things in there .
-Nate
Bill wrote:
>
> I have an 83 300sd, for about 3 years. Right after I got it, I put on a timing chain, adjusted the valves, and timed the pump. I alao repalced the fuel tank; reason for changing, it had diesel secrets fuel ran in it, and the fellow had fueled it with one batch, that had some hardern to the consistance of plastic, and changing the tank proved easier than cleaning the tank. Since then it has ran on bio diesel B 100, except for cold months, B 80. and no problems, other han glow plugs, and flex pipe between exhaust manifold and exhaust pipe.
> In recent history it will crank up rought, resembling bad glow plugs or fuel starvation, But unlike glow plugs, the cylinders do not start firing in a few minutes. On fuel starvation, fuel flows freely, when the plastic pre filter is removed . I did have some black stuff in the pre filter, reminding me of a deterioating fuel line . I replaced the fuel line on both sides of the filter, as they where starting to deterioate, due to bio diesel.
> It appears no one cylinder is missing continiously, but at random. After a bit all cylinders will start hitting. measuring the length of time it takes for it to start running smoothly on all cylinders. Milage wise, I thought at first trying that, but it varies from 6 to 10 miles. Then I noticed the temperature. It seems to smooth out after it gets to 80 C on the temperature guage.Or temperature is the one consistant factor that seems to determine when it will start running smootly on all 5 cylinders.
> Due to it seemly missing at random on different cylinders, I rule out cylinder compression. Plus it fires up almost instanly, the enginge is spinning.
> With the temperature indication, I am thinking valve adjustment. My reasoning fot this line of thinking is they are adjusted cold, not hot, if I remember correctly. If I am thinking correctl;y, that would cause a clearance difference on them between hot and cold. Can anyone familure with this confirm or dis confirm my thinking on this.
> My only other thought would be pump timig, but I can not see how engine heat and medal temperatures would effect pump timing, the same as it would on valve clearance . Although metal wear over time might effect both of them. Again anyone with expierence , thoughts on this.
> This is our main driver, so I do need to resolve it. I am no longer able to do much of this work myself, but my son is going to adjust valves and pump this week end, I hope.
> And although the mercedes from this era is very forgiving in bio diesel sins, I did have a spree for about two months, where I was not getting the best fuel possible, or I was screwing up.Too much soap possibly being left in the fuel. Soap of course means KOH, not always washing out clean, which also means some water left in. I understand this could etch and foul injectots up. I do not know how it would effect the pump. My fear of course, is did I push my luck too far in this area. Or was the forgiving engine, not as forgiving as I thought it was.
> As stated valve adjustment and pump timing are my next step, but are there any other areas I could be over looking, to find the reason for this miss. Bill C
>
