Injection pump getting fuel?

[Ahealey12]

I noticed the other day my injection pump filter would release a bit of oil out of it when revving it high. Decided to replace the oil and found it was very high. 150 miles later it’s high again and seems thinner so my assumption from reading posts is it’s fuel getting past the o rings or gaskets in the pump.

Car runs amazing besides trans issues. Is it a huge job to replace just those seals? Looking at removing pump shouldn’t be hard but wondering how many adjustments I’ll mess up when i remove everything? Guessing this is type of kit i need? I’ve done a lot of reading on it. I don’t think it needs full rebuild as it runs great.

But then again I’m reading this thread https://www.sl113.org/forums/index.php?topic=790.0 that it should just be the oil that seals it so even more confused now lol.  Should i try thicker oil? Is there a chance i didn’t get all the oil out last time? It was very dark black first time. Just looks full now not black still oily can’t tell for sure it’s gas. It also is not overflowing from the filter anymore.

[BobH]

Hello, i'm sure you must have read this, but if not:

https://www.sl113.org/wiki/Fuel/Injection

[Ahealey12]

Yes read through this multiple times.

[ja17]

It looks like those just external seals. I think your problem may be more serious internal seals?

[Ahealey12]

That’s what I’m worried about. Just so odd that it runs so well from what I’ve read on those seals.  Im gonna try to drain again today and retest it. Joe- do you know if we can run thicker oil at all to help? Everything I’ve read is that the oil should be a high enough pressure to seal the plunger from the gas coming through. Or I’m wondering if it’s that i have a pressure issue from the line to the pump which I’ll try to check tonight too.

[Ahealey12]

Tried to test oil pressure on my lunch break today. Oil pressure is good to the top of the injection pump so that’s not the issue.

[Benz Dr.]

Oil pressure probably wouldn't have much effect on whether the seals work or not. IP can work normally and still leak like sieves.

You need an IP rebuild.

[Ahealey12]

Had a great conversation with Blackforest
https://www.blackforestllc.com/ today. He gave some great insight and also some ideas to keep her running till rebuild time then I’ll be sending to him later on for a full rebuild. Truly appreciate all the help this forum has given to my little old car!

[Kevkeller]

Can you share what he said?

[Ahealey12]

After further discussion with him (he might chime in too i didn’t want to say anything wrong) it is most likely more just oil getting by as I’m not getting any fuel smell and still good gas mileage. I’ll be monitoring while i drive it (i drive this car every day) and checking levels and removing as needed until i can get the rebuild done this winter. From what he said (again hope I’m close) the bottom o rings under the plungers will get hard over time and allow the oil to come down from above overfilling the oil in the earlier self contained units. If they get bad enough you’ll also get some fuel as well so it’s good to be cautious on this as if fuel is getting there then you’re gonna start wiping out the bottom end of it. Since mine is truly feeling and smelling like oil not fuel i can assume that it’s the case here. I’d assume it’s been like this a long time as i know my grandma’s mechanic wouldn’t have touched the injection pump.  It is something that does ultimately need a rebuild though and i will be doing asap. Most likely this winter when i won’t drive it.

[rwmastel]

From what he said (again hope I’m close) the bottom o rings under the plungers will get hard over time and allow the oil to come down from above overfilling the oil in the earlier self contained units. If they get bad enough you’ll also get some fuel as well ...

I don't have an extension knowledge of the MFI pump, but don't the plungers only have fuel above them?  The fuel they are pumping to the engine?  What is the source of the oil above the plungers?