MFI Oil Leak?

[A.T.]

What is that little black cap on the front of my MFI pump just above the drive sprocket? What does it do and why is there oil leaking from it? I've got about 50 miles on the car since the freshly rebuilt MFI was reinstalled. The photo was taken after a degreasing of the engine to locate the source of the leak. I'm really hoping I don't have to send the thing back to Hans at H+R.

Thanks for any info.

[roblav]

It looks like a non-factory attempt at lubricating the pulley and belt.

[Chuck Miller]

The MFI pump is pretty mystical to me but...

But if I'm reading the manual right:

The rubber cap covers the plunger control rack. There's a hole in the end the rack to check it's tension.

However, the oil return outlet is below this location so theoretically it shouldn't leak.

Sorry that's not much help...

[Eric911S]

Hello: I would check that the drain back tube from the pump to the vent cover is clear(no plugs). If that checks out ok then run the pump with the black plastic cover off. If there is oil coming out of the end of the rack you will have to send it back to Hans. Hope this helps. Thanks Eric

[spydr32000]

The black plug/cover in question is just that, a cover for the inspection hole. This is a common cause/source of an oil leak, if you can get another cover then replace it, if not fit a hose clamp to it firmly, without over tightening it and your leak should be fixed. Easiest oil leak fix you'll ever do! The reason the oil leaks from here is because there is a lot of oil spraying around inside the pump. The cap over time wears, becomes loose and no longer seals as it should.

[A.T.]

Mike,

The cap is definitely loose. It lifts away from the pump about a couple mm. but doesn't pull off easily. Not knowing what it did I was afraid to pull too hard. It looks like it has been pried. There is a little damage along the bottom edge. Should it just pop off with some encouragement? Does it normally fit snuggly?

Eric,

I'll check the drain tube as well.

I'll give Hans a call as well.

Thanks guys.

[spydr32000]

The cap will gently pry off but if it is showing damage then be careful, if you can get a replacement, do so before removing it,if not, just fit a hose clamp to it. It will seal up by clamping it, if you want to be sure then squeeze some silcon around the base of the cap before tightening the clamp. Some times these caps can be hard to get!

[Walter Stockton]

Very interesting thread. My MFI has been leaking since being rebuilt about a year and a half ago. I was just about to send it back to Hans at H&R, but now I think I will check out the suggestions you guys have made here.
Thanks

[A.T.]

Hi Guys

Thanks for the tips about clamping the cap. I replaced it with something appropriate and clamped it. Problem solved? Nope. Unfortunately it appears to be leaking from behind the drive sprocket as well. I spoke with Hans. He thinks it's the oil seal around the shaft and says it's an easy fix. My mechanic is fairly certain it's not an issue of a plugged oil return and is having a local MFI expert (?) change out the seal, but also warned that the shaft may actually have enough wear at the point of contact with the seal that a new seal may not be effective either.

Any other opinions.

Thanks for the help.

Walter, how did you make out?

[rick2]

Give Gus at Pacific Fuel Injection a call. Or Matt Blast.

Pacific Fuel Injection (Gus Pfister)
Suite B, 153 Utah Av
South San Francisco, CA
Tel. 650-588 8880

Eurometrix
228 Boston Rd
Groton, MA 01450
Tel. 978- 448 2557 (Matt Blast )