Thanks! Yep, it`s getting there, although newer obstacles keep coming up along the way... I managed to start the engine the other day, it ran for about 2 seconds then died. Kept cranking, no response... I pulled the outlet fuel hose off of the pump and shorted the fuel pump relay. Gas was flowing but i could easily stop the flow with my thumb. That`s certainly not enough...

So I went ahead and pulled the pump assembly:

http://986forum.com/forums/uploads02...1602991159.jpg

This hose snapped right away:

http://986forum.com/forums/uploads02...1602991239.jpg

http://986forum.com/forums/uploads02...1602991266.jpg

Removing the pump from the bottom of the tank took me quiet a bit of time, it was really stubborn and the grip of my hand was not strong enough to twist it. Finally I got it off using an oil filter wrench.

http://986forum.com/forums/uploads02...1602991282.jpg

Ok, so here`s what I think happened: the pump was totally fine (it was replaced some time before because the original is not exactly like this), but the connecting lines became very very brittle and fragile, and broke immediately after being pressurized. The car was sitting for 13 years with the tank 3/4 full of gas. I think gas goes bad over time and somehow becomes aggressive to various materials, like plastic.

http://986forum.com/forums/uploads02...1602991298.jpg

Insulation of all the wires are destroyed too, on the pump and on the sending unit as well.

http://986forum.com/forums/uploads02...1602991314.jpg

http://986forum.com/forums/uploads02...1602991328.jpg

The pump by the way is a VDO unit, same as for Audis and VWs.

http://986forum.com/forums/uploads02...1602991348.jpg

Are you gonna replace the hoses with some OEM plastic stuff and the crimp clamps?

I have a low pressure pump sitting in my frunk for when my OEM pump gives up the ghost. I think I'll just replace my internal hoses with rubber fuel line and worm screw clamps.

Yes, I had replaced those with some fuel lines I found in my garage but only for temporarily, till the other pump arrived, because I wanted to start the engine. I wanted to replace the pump anyway because I had dropped it by accident and the outlet port broke off which I glued back with epoxy. But the hoses worked totally fine. Here`s how it looked:

http://986forum.com/forums/uploads02...1603075940.jpg

http://986forum.com/forums/uploads02...1603076368.jpg

http://986forum.com/forums/uploads02...1603076453.jpg

Pretty ugly, but worked for 5 days :D
When I got the new pump I swapped them.

Here`s a shot of the new pump when arrived. It`s a genuine pump with low miles, identical to the pump I had in the car before, and the label says it`s for the 987... It fits perfectly though. It also looks better built than the original 986, it`s a more sophisticated design: here the pump is sitting in a separate housing and suspended on rubber dampeners. If you scroll back, you can see the rubber suspension in a previous post.

http://986forum.com/forums/uploads02...1603080803.jpg

I wanted to see the condition of the pump that I replaced. It`s not servicable, because the aluminum casing is crimped on the motor, so I had to peel that off destroying the pump housing. Doesn`t matter because the output port was broken off anyway.

Here`s the rotor with the actual pump unit. It`s basically two pumps on the same shaft: a low pressure pump and a high pressure pump. If I understand correctly the low pressure plastic pump is there for filling the pump chamber with fuel. This probably helps maintain a steady pressure regardless of the fuel level in the tank, also keeps gas around the motor all the time for cooling, even when the level in the tank is very low.

http://986forum.com/forums/uploads02...1603080914.jpg

http://986forum.com/forums/uploads02...1603081017.jpg

The high pressure pump is a trochoid pump with steel rotors spinning in between ceramic plates. This pumps gas upwards through the electric motor all the way to the injectors and from there back to the tank.

http://986forum.com/forums/uploads02...1603081035.jpg

http://986forum.com/forums/uploads02...1603081060.jpg

Everything looks pretty good, except for the commutator being pretty worn down.

http://986forum.com/forums/uploads02...1603081091.jpg

Interestingly the carbon brushes look barely worn.

http://986forum.com/forums/uploads02...1603081123.jpg

If you ever wondered what`s in the top section of your fuel level sending unit, here`s the answer: a big steel ball. I assume the function of this is that it closes the breather line in case the car is upside down to prevent gas spilling all over the car. Good to know i don`t have to rush out from the car next time when i flip it over... If you have a better explanation for the role of this let me know.

http://986forum.com/forums/uploads02...1603081168.jpg

http://986forum.com/forums/uploads02...1603081193.jpg

I had to rewire the sending unit because the old gas stripped the wires almost completely.

http://986forum.com/forums/uploads02...1603081224.jpg

Long story short, the engine runs now with the new pump. The car is still jacked up on the driveway, I need to change all the fluids and I need to buy four new tires because the old ones all got oval.

I'm amazed with this thread, as always!

Can we have a video of the engine starting up and running? :D

I bet there are a lot more of these out there than people realize, which is why the motors are so nasty inside. I’m guessing mine is like that after only 70k miles by the oil vapor smell I frequently pick up. Sad they couldn’t use a better material. I could fix it but don’t feel like digging just yet, wait for a bigger problem.
Love the thread, thanks,

And more importantly, the engine will run rough because it loses vacuum through the filler tube. It`s a common failure point on these older cars where plastic parts become brittle.

I uploaded one here a while ago when I was tackling the idle control valve issue, I have a separate thread about it somewhere:
https://www.youtube.com/watch?v=8C2ZBcO4WZY&t=4s

I`m at 1000 miles at this point after the rebuilt, so far so good :)

Thanks!

For some reason, it sounds a bit different than the one I have (Boxster S 2002), although mine also has a nasty sound when starting it up when it's cold... I hope it's just the starter motor grease going old :confused:

Anyway, thanks for the thread! I'm sure this will push me on fixing some of the issues I currently have, and doing some more maintenance on it :)

End of story
 

Two years and 12000 miles later:

http://986forum.com/forums/boxster-general-discussions/82477-engine%60s-gone.html

wow if all this work is, as in his words (an armature hobby mechanic) i think im at least 30 years of hobby mechanic experience away from being able to do this to THIS extent. I did also follow up on that post with the failure.

Truthfully it was not even at fault to your own which was the hugest downside. A lack of online information regarding the rings really does make all the more difference between a very successful rebuild and catastrophic failure. An unfortunate ending but a very successful process i will be using towards one day taking out my current 2.5L and swapping a used one in

I don't think the rings were he real problem here, it's more like a combination of overheating and the previous repair involving new liners installed that I missed. Yeah, this much work for a 20+ year-old car which can fail any time for some other reason is not really worth it. Regardless, I'm just about to do another rebuild like this which makes me an idiot for sure.