Troubleshooting Possible Injector Issue

[Salty]

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........understand these engines are really Perkins anyway.

Might not even be Perkins !!
My MD2020D was made by Shibaura in Japan before being sold to Perkins who then sold it on to Volvo. For sure the injectors will have been made by a firm who specialise in such parts before being supplied to the engine manufacturer, maybe Lucas, CAV or others. You could try your local motor factors, someone there might point you in the right direction, they might even have a direct replacement part on their shelf or at least be able to look it up in one of their catalogues/websites.

Let us know how you get on as mine have not been serviced either in sixteen years, and as I said in an earlier post above, I was warned off touching them unless I knew there was a problem.

[sailprincess]

Ack, my post got highjacked 

We are still having the same problem. I realize it has been some time, but we have since removed the mixing elbow (suspecting a clog but there wasn't one), the heat exchanger (the end boots were leaking some, so replacing), the fresh water pump (was corroded, we are replacing) and the alternator (got the brushes and bearings cleaned). There are some bubbles in the fuel return line.... Here is what we have done so far:

replaced all fuel line hoses and clamps
removed and replaced original fuel shut off valve
switched the pick up tube with the return tube (just in case the pick up tube was an issue, even though we pressure tested it)
brand new racor filter and full unit
brand new volvo fuel filter

The engine starts no problem but it drops huge in RPM if you give it throttle

[MarkTheBike]

Hi SailPrincess
I haven't re-read the whole thread but your comment '...bubbles in the return line...' jumps out at me. Is that normal for diesels? Are the bubbles there all the time or only when the motor isn't running smoothly?

[sailprincess]

The bubbles are there all the time. More throttle also equals more bubbles.

[Salty]

Were the bubbles there before you switched over the suction and return fuel lines? The fact they are there says to me that your system is allowing air into the fuel supply somewhere, and that more throttle just sucks in more air. After switching over the suction and return lines, was that just a temporary switch, and did you revert back to the original supply and return ?
Also suggest you look at the thread marked “Bleeding problem MD2020” where there are some useful comments, not least of which concern the primary fuel filter and possible air leaks from it as posted by Yngmar.

[MarkTheBike]

...the fact they are there says to me that your system is allowing air into the fuel supply somewhere, and that more throttle just sucks in more air...

Yup, that's what I was thinking. "More throttle, more bubbles" might answer the "drops huge RPM if you give it a bit of welly" comment. I think you have to track down where the air is coming from - a weepy bleed screw, cracked pipe, etc. - it won't be easy finding it but there definitely shouldn't be any air at all in the system. Your answer to Salty's question about bubbles when you switched over pipes may be telling, but by this point, I'd be thinking about replacing the pipes anyway (which don't appear to be on your 'replaced' list).

[MarkTheBike]

...forgot to add - you will, of course, only get bubbles in pipes/joints that are sucking fuel, not pumping it, i.e. negative pressure ones.

[IslandAlchemy]

If your engine is running well, then leave the injectors alone.

You cannot but new injectors for this engine any more, and haveing them re-built properly is expensive.

There is also the possibility that in removing and replacing them, that you cause other problems.

If it ain't broke.....