fve

this topic has been broached in the past, see:
https://rennlist.com/forums/996-gt2-...ont-start.html

Background: the east is sweltering. I drive my car down from Philly area to summit point. No problems. I get ready for the first run session, i am in staging happily idling when the idle becomes erratic then, dead. Restarting did not help. Long story short, tried a number of things, the folks from Doughtery's in West Chester (providing support for those with deeper pockets than yours truly) were nice enough to look, but i had to trailer home after a grueling day envying the hot, greasy fun others were having.

Get home, less than 1 bar pressure in the fuel line. After checking a few other things, the fuel pump comes out. F'n POS little hose. See images.

In any case, with the heat in the east, i could only imagine that there could be others in this boat. low fuel, hot day/tank, cold gas added. Rinse and repeat. Eventually something will give.

Thought: i saw other mentions of failed fuel pumps. I wonder how many really fail in such still relatively new cars. Or do "they" (dealer, mechanic) just throw in a new part (it comes as a whole assembly, part # 996.620.057.90) and that will be $1300 thank you very much. FYI. If no fuel, it may be worth a look at the hoses.

Question: any good suggestions about hose replacement that will tolerate pressure and constant immersion in fuel? I was thinking silicone, but am open to good ideas.

thanks, fve

vtwin996

It happened to me on the track; quite common. I am not sure what was used, but I take my car to Eurosport here in Chicago and they told me Porsche use crappy hoses and replaced it with something more durable. Not sure what was used.

Mr Michael B

Ohhh yes. Common. I have done several of these in GT2 and GT3. At one Autobahn Raceway event a GT2 customer had a failure. Eurosport did a temporary repair there too but the fellow did not make it home. They reported to him that it would need a fuel pump (expensive). And that is what he got later.

After further review though I studied some inventory for immersed fuel pumps and found that Volvo had a fantastic replacement hose that came along with an in tank fuel filter. The hose was superior to the Porsche part and was nearly a drop in piece once dis-guarding the filter. It also seems to take the "abuse" of sitting within USA fuel rather well Vs the GT rubber section.

Now when I see the bad hose I see no need to perform a pump replacement (confirming the pump is still good), just replace the small rubber section and go.

SH || NC

Have a p/n?

fhp911

wow !!

another thing to worry about.

I was at the Summit Point event -- it was HOTTTTT !!!! (brutal, in fact)
My '04 GT3 didn't falter but maybe it will next time?

What is the feeling out there? Should this hose be replaced as a Preventative Maintenance gesture?
And should we replace it with the stock Porsche hose, or use a better one (like the Volvo one mentioned above) or what?

Does anyone know what the racing teams use? 24 hours at Daytona must put some stress on this hose, right?

fve

I have been doing some reading and research. Gates make a fuel submersible hose, but it is only rated for 500 psi (burst). I read in the other post that the hose for Porsche is rated for 1000 psi, but i do not know that for a fact.
Link for Gates hose: http://www.gates.com/brochure.cfm?br...ocation_id=541
Apparently it is readily available at Napa and a quick search found lots of options over internet.
I will look into the Volvo hose Monday when i can reach a dealer.
--fve

ninerguru

Manual says that pump test pressure at engine is about 4 bar, which equals 58 PSI. I think a hose with 500PSI burst pressure should be sufficient...

Looks like removing the pump is not that hard just removing battery, batt. holder and undoing 3 lines and an electrical connection. Hardest thing looks like removing pump holder ring, large channel locks? What is the pump body diameter, just to get an idea?

Can someone measure the hose inner diameter? Might be worthwhile to buy a foot of hose and a couple of clamps and keep them in the track kit. If not for you, for one of your other GT3 track buddies. Might save the day... Lou

fve

I just got home from work, ate dinner and now... for some measurements.

500 psi: i would hope so. I would guess that the pressure rating is less important than stability (from temp and constant immersion in fuel). I took the tube off entirely and it was bursting in several spots, including under one of the clamps. I tested it with water and it was leaking like a grannie's bladder.

Pump diameter: 4 and 3/8 inches, 11.2 cm.

Hose info: Inner diameter = 7 mm, outer diameter = 13 mm. Marking include "NBR" (search indicates Pressure Resistant Pure Nitrile Inner Tube) and " T 83 023 158" (i could not find what this stands for, using numerous combo of spaces, dases, dots, etc.).

Track buddies: i fully intend on a 2' section for future use for me and any one else in need. Tough lesson (another one) hopefully learned.

For what it is worth, the toughest part was not getting the blue pump assembly out, but getting the little off-shoot siphon part. while int eh tank, you have to feel around a little blindly until you find a little clip that needs to be depressed to take it off and get the whole mess of parts out. I will take a photo in the next day or two. Once you see it, it becomes clear.

Also: the actual fuel pump itself is in the blue housing along with the wires and a mess of tubes. If i had to replace the pump, i would would just get a good aftermarket pump and put it in there instead of the whole assembly--which is a pretty penny or two.

-fve

ninerguru

7mm inner diameter. Gates catalog shows 5/16"=8mm. Close enough... How did you get the collar holding the pump/hoses off? I was asking size to see if pipe wrench would work. Perhaps using a punch & hammer can remove the locking ring. I would like to see photos of what you are talking about. From the manual, it looks like pump is locked at bottom of tank. Needs about 15 deg left turn to unlock. Would like to understand siphon part you are referring to... Thanks for taking the time to show us... It might come in handy some day. Lou

Mr Michael B

I cant recall the Volvo number but I am sure I have the part number at the shop.

The key that everyone is ignoring here is that you cant comfortably use just bulk hose. The turn that this hose makes is MUCH to radical to just bend a rubber hose of this diameter. It will (and does) kink. Bad.

That is why I found the Volvo hose. It comes with about a 125 degree turn already in it.

And... More tid-bits. You can do this swap without even removing the pump. I did one on the side of the road - with a set of side cutters - and new pinch clamps. It was not easy mind you (gotta pull the battery, and the tray, and THEN take off the sending unit etc...)

Anyhow. I do think of this as a "preventative fix" - and if you have not done it in a GT series car, then you should.

fve

I would greatly appreciate the volvo part #.

As far as the kink, i was thinking about what to do about that -- i was not sure how much of a problem it would be, but apparently a significant one.

As far as a in-the-tank fix, now that i have the parts out, see how they are put together, i could imagine it but it woud take someone with more patience and dexterity than myself.

Thanks for the info.

---fve

911SLOW

Guys very interesting thread. Very clever idea worth the trouble.



John

fve

Oh, as far as removal of the collar, i used a large clamp, i had a tough time getting a pipe wrench in the limited space. I am sure that the punch/hammer method would work too, i would be concerned about mashing up the plastic though.

Hopefully these photos will clarify some of it.

Photo 1: the float and fuel level mechanism, since it it out. A friend of mine is having an issue with fuel level and for those, this may help.

Photo 2: the hose with the built in bend. Note the bracket and the big blow out. The arrow to the small area that was failing under the clamp!

Photo 3: The whole pump assembly. The arrow points to where you have to depress to pull the hard plastic siphon part off, otherwise it will not come up out through the tank opening. Note how he actual pump sits inside the blue plastic enclosure, which is hollow. I guess that is to ensure that even if the tank is low, that the pump always sees fuel for pumping and immersion/cooling. I suspect that it also limits temp shock (by limiting mixing of new fuel and the fuel immediately around the pump) when you add cold fuel to a hot tank.

Photo 4: top view. The pump again sits in the blue plastic, held in place at three points. I suspect that one would not have to replace the whole assembly (costly...) and just get an appropriate pump to put in the blue assembly. the arc is where the failed hose would sit.

Hope this helps others out there.

-- fve

SH || NC

Awesome info, thanks guys

ninerguru

Thanks for the great pictures! A couple of questions... Looking at the pixs at the beginning of thread, it looks like the curved hose connects the piece with what seems to be a mini inline filter to the white serrated connector. Correct? What connects to the little blue tube extending from the pump top (3rd picture, in lat post)

Also, I'm assuming the 2 hoses and elect. connector connect to the bottom of the fuel lever sender. Are hoses a snap type connection (like an air hose?) or did you use a tools like GM/Ford uses?

Did you have to disconnect the serrated hose from the siphon to the pump in addition to doing clip to get pump out? How does it disconnect? Can it remain connected and still be able to remove pump?

How is the blue assembly held in place in the tank? Twist lock?

Once again, thanks! Looks like it might be good preventive maintenance... Regards, Lou