Nicholbry

I have a '90 S4. I am about to drop the gas tank, remove the old in-tank pump (I'm aware of the issues with the collar/tank stripping so I'll go easy) and replace with the strainer instead. Someone recommended the earlier fuel pump (pt # 928.608.104.02) that was used on the pre '90 cars instead of the original pt# 928.608.104.03 that was used on '89-95 cars. The recommendation had something to do with the earlier pump having a better flow rate (or something like that, I can't exactly remember).

A few questions:
1) I know that I'll need the different hose to go from the strainer to the pump, but can you guys tell me anything else that I need to know regarding this swap to better help me make the transition?

2) Any other parts I need before I start ordering (I've already got a new pump-to-filter rigid line, new crush washers, and a new filter)?

3) Is there a benefit to using this different pump than the later model pump; if so can you elaborate?

4) The strainer obviously won't require the wires. Can I just tape these out of the way or will it send a fault of sorts to the computer if I don't use these wires?

5) I plan on replacing the seal for the sending unit in the top of the tank and pressure wash the interior of the tank. After I remove the internal pump and sending unit is there anything else hidden in the tank that I might damage from cleaning the inside of it that I haven't considered?

Thanks for you help.
Nicholas

Herman K

Changing the top seal, why? Is the sender bad?

Pressure wash the interior of the tank, why? With the internal pump out you can do a pap smear test of the bottom of the tank.


Looks like you trying to create more work than you need

928 at last

If future engine/fuel delivery mods are in the cards, Check out AO's thread on "Dont' use the in tank Pump Ever".
I went with Murph's modifed strainer/line assembly and the 044 Bosch Pump from Roger.

jpitman2

Std procedure for single external pump cars was to tape up the spare leads for the in-tank, so you are correct to do that - just ensure the two ends wont meet. I have heard of tank interiors being pressure washed before, so that should be ok. Just give it time to dry right out before re-assembly.
I usually replace filters on the bench as its easier to ensure everything is secure when you can get at it properly, rather than having poor access under the car, so I suggest bench assembly.
jp 83 Euro S AT 53k

jon928se

I pressure washed the inside of the GT tank at approx 16 years old as it was lined with red dust from the dirt roads on the island we lived on in NZ for a year. Never did figure out how it got in there but it was there. If the tank's coming out anyway along with pump and sender may as well clean it out.

jeff spahn

If you are pulling the tank mostly for the reason of removing the in tank pump, don't. You can easily do it with the tank in the car.

finally!

what jeff said, I changed both my fuel pumps, 89 S4, with Sean a few weeks ago, no need to remove the tank.

AO

I don't think the hose is different, but if it's never been replace, probably not a bad idea to swap it out.

That should do it.

Didn't know there was a difference. As long as you get proper fuel delivery, you should be good to go.

Yep. Just cover them up with some heat shrink and tape them out of the way.

Dunno... never replaced the sending unit.

Jeff928S4

If you are changing out the in-tank filter for the strainer, you will need a new hose. Check with Roger for this hose.

I just went through the whole dropping the tank/taking out the in-tank filter (and cleaning the screen)/cleaning out the lower section of the gas tank.

This thread may be of some help....

https://rennlist.com/forums/928-foru...ics-fixed.html

Nicholbry

Thanks guys for your input. I'm bringing the tank down for a couple reasons. 1, the straps have some corrosion starting and I thought I would get them powder coated along with the tray/pans associated. 2) The tank has likely not been cleaned since new. 3) I've got a leak at the external pump area from suspected crush washers deteriorating and I'm of the mindset that if I've got to disconnect that whole pump/filter assembly I just as well take care of the entire fuel delivery system back there while I've got the tools out and car jacked up properly. At least this way I can rest knowing that this is one area I'm likely / hopefully not going to have trouble with for many years to come. For those that don't know, my engine was recently rebuilt from case up, so my goal is to get all systems in as new condition as I can since the engine is new. Truth is........I want a factory new 928S4; so to that end.....

Ok, so the truth is I'm obsessive/compulsive.

Back to the topic at hand.....
So I need:
1) New rubber hose that adapts the strainer to the external pump
2) Strainer
3) Different pump that originally accompanied strainer-equipped cars (Roger T. recommended).
4) Stainless steel clamps for the rubber hose.
5) Check out Jeffs928S4's link.
6) New seal for sending unit

Anything else that I don't already have (as previously mentioned in my initial post) that you guys can think of?

If I take out the in-tank pump and sending unit is there anything else inside the tank that might get damaged from pressure washing it, or is it basically an empty plastic shell at that point?

I read every reply and apologize for not being able to thank you individually for your recommendations, but I do thank you.

nc_growler

Since you are dropping the tank, I'll remind you of the hint I saw in another thread that mentioned when you go to re-attach the straps at the rear, go purchase a longer version of one of the two bolts (about 25mm longer). Use this bolt to tighten up one of the straps (it's much easier than trying to lift the tank and align the bolt. Then getting the shorter bolt into the other strap is simple. Then remove the long bolt and install the shorter.

ROG100

Two different hoses for the intank pump and the strainer.
Other than that you are good to go.

waynestrutt

[QUOTE=Nicholbry;8900734]Thanks guys for your input. I'm bringing the tank down for a couple reasons. 1, the straps have some corrosion starting and I thought I would get them powder coated along with the tray/pans associated. 2) The tank has likely not been cleaned since new. 3) I. At least this way I can rest knowing that Back to the topic at hand.....
So I need:
1) New rubber hose that adapts the strainer to the external pump
2) Strainer + BOTTOM TANK SEAL

3) Different pump that originally accompanied strainer-equipped cars (Roger T. recommended).
4) Stainless steel clamps for the rubber hose.
5) Check out Jeffs928S4's link.
6) New seal for sending unit



I just finished dropping my tank. When you remove the large cap(pass side under hatch) covering access to the fuel sending unit you will see a 3/4" hose with clamps running though the body to the fill neck. Be careful or the plastic barb nipples will break. when you have the sending unit out resist the urge to poke something in the bottom hole to clean it. There are 3 fine hairlike wires that must not be broken if the sending unit is still good. When unscrewing the intank pump ,if it does not move use penetrant do not force or like me you will have the metal insert molded into the plastic tank come loose. It is knurled on the outside molded to the tank and threaded inside. If you have a problem ,as I did ,I very carefully used a heat gun to warm the abs tank outlet and forced the fitting back in with a liberal coating of 2 part marine gas tank epoxy. After curing for 2 or 3 days I washed the tank out with a gallon of acetone (not more than 30 min. ) and rinsed twice with paint thinners. you will need to get a new bottom tank seal for the pump or filter screen. My car sat since 97 in my garage and had a 1/4" of tar in the bottom,and a seized sending unit and pump.
If you look up inside the rrww you will see a 7/16"hose from the tank fill line nipple to an elbow on the expansion tank.Cut it rather than breaking the plastic nipples and get Rogers fuel line kit. Take pictures of the intank filter etc layout to ease reassembly. This will not be a 1 day job.

the flyin' scotsman

The external pump and filter assembly can be removed as one piece....undo the hoses and pinch off or drain, remove the 4 nuts and washers and remove the assembly.

This way you can bench build as noted above.

Nicholbry

Thank you guys. These are the kinda tips/info I'm talking about. I appreciate it very much.

Nicholas.