1979 300td with alleged fuel pump deficiency
 

Hello:

All opinions and advice welcome. My mechanic has told me that my injection pump is shot. He also says that the lift pump is underperforming.

185k, 14k of it with two tank heated vegetable system.

The above, however, doesn't tell the whole story. Though the system is well designed (greasecar) and I've been careful about purging, I did initially have a faulty supply valve, meaning that for about a week in late fall I was occasionally running on a cold mix of fuels. Twice on very cold days the engine stopped running due to a 'plug' (I'm describing this w/o accuracy, and guessing, to some degree) of cold vegetable oil being 'released'. Then I figured out what was going on and everything was fine for the next 13 months.

Last month it wouldn't start. I got one more start out of it a day later and it ran just fine for 8 miles or so. The next day it wouldn't start at all, and hasn't since.

Any thoughts? I was under the impression that, while not desireable, this kind of abuse wouldn't likely be the demise of my IP.

Thanks very much.

If you can get it running and keep it running I would highly suggest a couple cans of Diesel Purge. It's a good thing to run through the engine especially when running Veggie oil. It also sounds like you could have air in the lines somewhere. Go through and make sure all your fuel line hose clamps are tight.

Also prepare for a barrage of Anti-VO post:rolleyes:

There was a thread on here within the last week about an injection pump with a stuck rack due to running on WVO. Look it up. Could be your problem too.--here it is:http://www.peachparts.com/shopforum/showthread.php?t=269800
There's also some recent threads on fuel pressure to the IP. Read those too. You could also replace your lift pump or at least test it. Not a difficult or expensive job.
All that being said, there are also quite a few threads on here about failed IP's due to running on WVO. Of course, I think the recent discovery of a stuck rack in the IP might apply to those other failed IP's also.

false alarm
 

Thanks for the ideas.

It was actually a really bad, and somewhat mysterious, air problem. My mechanic was able to start it by syringing fuel into the IP, and it seems to be back in business.

Does anybody know what sort of vacuum the lift pump should be able to produce?