Bill,
if I read correctly and am not inferring anything, your short hose between the outlet and pump had no clamps? How else could it pop off? Both the in-tank pumps I have with broken hoses had clamps when new. I got the 1/2" dia hose from NAPA, not the clamps. They came from a different auto electric place that has good (non-Asian) tools and related items.

 

No, it had both clamps, but I managed to work the hose off anyway. The hose just gradually worked off the outlet fitting as I flexed it back and forth rather forcefully trying to see if the hose would break. Here is a picture before I started testing the pliability of the hose. So, I thought I would replace the clamp. The hose is fine!

 

Well, my car was originally a C16 UK spec car (no in tank pump), but it had been in Saudi nearly 10 years when I bought it....and the only time it has ever been trailered home was when the external pump failed due to ingestion of foreign matter - which it duly spat out once removed from car and powered directly, then ran another 4 years until it and tank were replaced. This failure was the only one in 2 years of use in Saudi, at up to 120F, so I really believe that while some power may be lost in hot climates without both pumps, I dont believe it would stop you getting somewhere. Flow tests produced the specified results or better. Major problem was that the in tank filter was broken up, and could not be removed readily due to spinning the threaded insert. This was subsequently pulled out with brute force, tank cleaned up and insert glued back with epoxy.
jp 83 Euro S AT 50k

 

I had a similar failure with my in tank pump. I'm torn as to put another one in there or forget it and replace with a strainer only unit.

Louie, could you share what strainer you end up using externally before the outside pump?

 

Sure. However, I don't have the filter in now. I'm on a time crunch to try and get the car up and running for the 928OC meet in Denver and it'll be tight. Upon evaluating the situation and seeing that it will take some modification to the fuel pump/filter cover to fit in the extra filter, I decided to delay that part of the project. The filter is large enough to have to fit between and under the existing external pump and filter, and will need a bulge in the cover. It's 4.75" long and 1.5" diameter and will need hose barbs on each end too. The new replacement hose on the internal pump should last fine for a while and I'll put the external filter in next winter. I still have to flow the internal pump to see if it will flow enough fuel to be useful or a hinderance.

I purchased the filter from Aircraft Spruce and Specialty. www.aircraftspruce.com. Here is a link to the catalog page. http://www.aircraftspruce.com/pdf/catalog/Cat06164.pdf
The filter is near the lower right side of the page and is part number 05-28905. It has female 3/8" NPT in/out openings in each end. The filter element is very fine (25 micron) and is a real pleated construction. It's easy to take apart to inspect and clean. I had looked at several other types of filters and most were either way too big or had a dinky little disk filter element about the size of a quarter. The literature would say "pleated", and "high flow" but that meant that the filter material was only wrinkled a little. I wouldn't feel comfortable using those on a lawn mower. Summit has one that would probably work made by Aeromotive, but they give no physical size, and the price (expensive) is similar to the one from Aircraft Spruce. Even without the internal pump, I would want an external quality filter in front of the pump. I've seen too many of the 928 in tank filters crushed with holes in them. They get crushed by being dirty and the pump sucking them in. The in tank filter is too hard to get at for most to check until there is a problem, then it's too late. Here are a couple of pics of the filter.
https://rennlist.com/forums/attachme...d=105498&stc=1
Filter.jpg

https://rennlist.com/forums/attachme...d=105499&stc=1
FilterOpen.jpg

 

That's a very nice filter there, Louis... With one of those, you could remove the in-tank strainer with confidence. Nice find!

 

MTBE Perhaps? IIRC there were a series of car fires in CA after MTBE was introduced: fuel lines on older German cars were not compatible. High age coupled with incompatibility equaled FIRE.

 

Hmmm... good thing I stay far away from MTBE "enhanced" fuels then.... Maybe they should call it "Wreck-ron"

 

That's the plan if the in-tank pump doesn't work out. The problem is finding a place to fit it in.

 

DOH! MTBE. Not MBTE!

Have they finished banning MTBE in CA yet?

 

I'm not sure. I stay away from Chevron because of it.

 

As usual, excellent write up Louis.

I looked at a new pump today and immediately noticed the hose didn't have the "Hans and Frans" we've all come to appreciate and a secton of braided injection hose would make a fine replacement.

It also seems to me if more daily drivers aren't stranded in CA's summer gridlock, that is prolly safe the to just go with the pre '89 strainer.

 

After reading this thread, I decided to take my in-tank pump out and check it while I had my fuel tank out anyway (replacing 19 year old hoses and waiting on a replacement vent hose).

My in-tank pump came out very easily.. needed very little force on a 36mm spanner to unscrew it the first turn and fingers after that.

Sure enough as found by several here, I had the same hose failure - split between the two clamps.

Easily replaced with some 15/32 reinforced fuel hose - the shop produced it when i asked for 1/2 inch and handily it turns out that 15/32 is *just* big enough to go over the fittings with a bit of spit and a lot of wiggling, and small enough to re-use the original clamps.

Interestingly the filter on the pump had trapped some material, although I have no idea if that was before or after the rubber split.. but on the plus side, I found/fixed this before anything damaged my external pump.

Pics below.. of the split, repaired pump, and crap stuck in the filter.

 

The in tank pump on my GTS had the same broken hose when I first bought the car. It was pumping, but not pushing anything through to the secondary pump and filter. The in tank pump may be small, but my GTS ran like crap until I fixed it. The hose on my '89 had the same problem, which I also repaired. That's one of the first things I check now whenever I buy a 928 that uses both pumps. If you're going to delete the in tank pump, you may want to upgrade the external pump to one with a higher output than stock.

 

As I said in an earlier mail, my single pump car survived 10 years in Saudi at up 120F, and delivered the spec flow rate fine.
jp 83 Euro S AT 50k