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Old 10-17-2020, 08:49 PM   #181
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Originally Posted by pilot4fn View Post
Very nice built and great that you post us the updates to learn from! You'll be on the road in notime with this rate of rebuilt speed
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:



This hose snapped right away:





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.



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.



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





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




Last edited by Homeoboxter; 10-17-2020 at 08:51 PM.
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Old 10-18-2020, 06:54 PM   #182
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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.
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Old 10-18-2020, 08:01 PM   #183
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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:







Pretty ugly, but worked for 5 days
When I got the new pump I swapped them.
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Old 10-18-2020, 10:17 PM   #184
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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.



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.





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.





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



Interestingly the carbon brushes look barely worn.



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.





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



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.
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Old 12-19-2020, 07:58 AM   #185
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I'm amazed with this thread, as always!

Can we have a video of the engine starting up and running?
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Old 12-20-2020, 07:52 AM   #186
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Originally Posted by Homeoboxter View Post
Oil filler tube. Doesn`t look right.




Almost there
I bet there are a lot more of these out there than people realize, which is why the motors are so nasty inside. Iím guessing mine is like that after only 70k miles by the oil vapor smell I frequently pick up. Sad they couldnít use a better material. I could fix it but donít feel like digging just yet, wait for a bigger problem.
Love the thread, thanks,
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Old 12-20-2020, 08:40 AM   #187
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I bet there are a lot more of these out there than people realize, which is why the motors are so nasty inside. Iím guessing mine is like that after only 70k miles by the oil vapor smell I frequently pick up. Sad they couldnít use a better material. I could fix it but donít 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.
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Old 12-20-2020, 08:48 AM   #188
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I'm amazed with this thread, as always!

Can we have a video of the engine starting up and running?
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
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Old 12-20-2020, 12:53 PM   #189
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Originally Posted by Homeoboxter View Post
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

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

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