Low Lubricity Fuel System

thirdgoat · December 12, 2004

I have a 99 Tahoe, and purchased a Delco fuel pump online. I went to install it and found my existing pump has additional elecrical connectors to it. I bought a GM part 25314327, MU149 that was supposed to fit. Upon going in to the AC Delco page, is lists an additional pump that has the additional electrical connectors, listed as PN 25314341, MU 148, listed for use with the Low Lubricity Fuel System, K55. I also looked at my Service Parts label, but could not find K55.

Any ideas? And what is the Low Lubricity Fuel System?

Any help would be appreciated.

Thanks, Guys!

mcreyaufmiller · December 13, 2004

Could it be an alternative fuels pump?

thirdgoat · December 13, 2004

Could it be an alternative fuels pump?

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Not any alternative fuels, just good old-fashioned gas!

Turns out there are at least 2 different pumps for my application, of course, I had the wrong one. It's still running, but it is very loud, compared to other Tahoe's, Suburbans, and pick-ups. Hopefully I can replace it this week.

Thanks!

99-2door · December 14, 2004

Lubricity is the measurable quality of fuel to prevent or minimize wear in moving metallic parts in vehicle fuel systems.

The K55 pump is just what it says.... Designed to better withstand low lubricity fuels.

Low sulfur fuels have the side effect of low lubricity also. There are additives to counteract this.

cit1991 · December 15, 2004

Usually this applies to diesels. Diesel fuel (being heavy paraffin) has fairly good lubricity, or ability to lubricate sliding parts. A pump that runs well for diesel might not for a fuel that has lower lubricity.

A while back FedEx tried running their diesel backup generators (at their Memphis sort facility) on jet fuel (since they had lots of it on hand). The engines ran great on the lighter jet fuel, but all the fuel pumps wore out.

Diesel fuel that has been desulfurized has lower lubricity. When low sulfur diesel first came out, they had some problems. Now they add lubricity improver additives.

I have not heard of the problem for gasoline though (which has never had good lubricity).