Jengah

So here's an interesting situation. We were draining the old fuel, or at least trying to. The first problem we ran into was after we bridged the relay, nothing happened. We tried multiple times, but the pump wouldn't engage. So then we decided to go straight to the pump and hard wire it. That worked, but the flow of gas was anemic. It pumped out about half a gallon in a relatively steady stream and then spurted and burbled like there was air in the line. The motor was working hard, it sounded like a muted garbage disposal mixed with regular pump sounds. It defiintely wasn't the smooth whirl of a normal pump. So, the pump was barely pumping anything yet I still had almost half a tank of gas left.

Now follow me here... the first time the engine broke down it was from a dropped valve seat on cylinder 5 at about 80K, then it dropped another valve seat on cylinder 5 at 114K. In all the records, it doesn't appear that the injectors were ever replace - nor the fuel pump. Now I'm aware of Jake insisting that new injectors are used for engine rebuilds due to the problems with poor spray patterns and consistency causing cylinder/head issues, BUT is it possible that a poor fuel pump could also cause these problems?

On a similar thread, how long should a fuel pump last?

Do the symptoms sound like a failing fuel pump or possibly something related to it (remember the issue with not being able to jump the relay)?

Thanks

theprf

Pull of the screw cap and inspect the fuel lines from the lid to the pump. They often split inside the tank, which does reduce both pressure and flow, and can cause lean conditions.

e30rapidic

how's the furl filter? I've also read that the fuel pump won't run for the full time unless hooked to the Durametric tool. Not sure if that's true or not!?

Just jumped pn your thread as my block had bad scoring and off to LNE for a 4.0 fix and my heads are off to Hoffman this week.

Going to be an impatient wait on my behalf for all the parts to return!

Jengah

Thanks Prf - i was thinking the same thing. I guess with 114k on the car and the original pump and lines (the seal was still original on the cap) it's just best to replace the pump and lines in the tank. Ugh - another $750... LOL

Jengah

Hey - sorry about your engine, but let me know if I can be of any help on your project.

So, the 2nd generation of 996s don't have a separate fuel filter, it's integrated into the pump.

Not sure about the Durametric thought, I'm mcurious if anyone else has heard this.

Thanks

Byprodriver

The 2002 heads are known for loose valve seats from new.

theprf

You can replace the lines without replacing the pump. Make sure you get submersible fuel hose.

jandackson

Replace the pump. It’s failing and will either leave you stranded when it quits or will not put out enough pressure causing your new rebuild to run lean. Cheap insurance either way.

Jengah

Do you know of a way to replace the venturi tube lines (used on the Turbo and AWD models) with submersible hose? I came across one thread in the turbo forum that mentioned doing that instead of using the $350 part from the factory (P/N: 996-620-113-00)

theprf

My notes say that either GATES 27093 SUBMERSIBLE FUEL LINE HOSE can be used, or the accordian hoses can be sourced from tiautomotive.
pwdrhound wrote "You can get them from TiAutomotive, the manufacturer of Walbro pumps. Various lengths in I.D of 8 or 10mm"

I assume that's what you're asking?

Jengah

Yes, do you think it's as simple a job as replacing the plastic lines and re-attaching to the hard plastic parts? Seems crazy that Porsche would charge $350 for four plastic fuel lines. I don't have the part out, so I can't see if there is anything mechanical in the part.

Thanks for the help.

theprf

Yes, it's that simple. The $350 Porsche part includes the "sucking jet pump" as well as the lines, which somewhat explains the price.

NB. My comments are based on the 996 Turbo, which should be the same as the 996 C4 or C4S fuel tank & pump.

Jengah

Thought I'd share an update from last weekend's work. This is the space I had to work in after getting the car dropped off at my house. I've got a steep driveway behind the car that would have been almost impossible to push the car into without at least 4 guys. Gotta say, you feel pretty good using 10 ton jack stands in back!!!


Decided to put the engine and tranny in together as a unit.


Had a little help bolting in the tranny from a four-legged friend:


Engine in (sorry about the bad photo. And I'd love to hear if there are any tricks to getting the AC in. It took us over an hour and the bracket next to it got pretty scratched up. It sure came out easier. Is it just a Rubik's cube and you need just the right angles and turns to get it in properly?


Next steps:
- torque cross members
- install a few more hoses
- connect PS lines
- replace fuel pump and pick-up lines
- fill coolant and bleed
- fill oil
- start break-in process

Mpfaff

Good luck on first start. Please follow proper starting protocol I.e.do not pre fill oil filter etc.
Disregard of course if you are already aware.

Jengah

Beleive me, I will. I’ve read the RND engine break in protocol about 10 times and have it printed out for referral.

I’m the most nervous about the one second starts to build up oil pressure.