Small tutorial on repairing the 550 Fuel pump

Hi all,
as explained in another topic on the technical Q & A, I very recently bought a 550 which the selling garage had fixed a fuel pump problem of. Or so they said.
On the trip home I got a SDL, and in the end arrived home with 6 cyl instead of 12.
When I checked the fuel pressure , the right hand side showed 0 pressure, where the left showed around 50 psi when connected to that side's Schrader valve on the fuel injection rail.
So I disconnected the fuel filter on that side (good accessible near the rear wheels each side after removing the plastic aero covers), and no fuel came out. Ok, so a clogged line from the pump cover to the filter, or a broken pump. As they garage said they had renewed the filters, but the things where corroded, I started to get a bit suspicious about the quality of their repair.
Advise of FatBillyBob to use the schrader valve to drain the tank until the level was much lower, hopefully below the cover.
I disconnected the 2 lines that go to the pump cover each side. The pump covers are behind a plastic protection cover that is bolted to the rear bulkhead. After removing that, you can clearly see 2 covers with each 2 lines and an electrical connector.
The cover is held in place by a very large 10 cm circular ring nut, which needs a special tool to remove.
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To remove the 2 plastic lines (shown here on the left pump), simply remove the nut in the middle of the bracket that holds the 2 lines, and you can wiggle the lines out. Be careful with the 2 o-rings that seal the lines in the cover. Inspect them for damage, but preferably renew them with fuel resistant new ones.

To remove the ring nut, I made an ugly but effective tool from 4 mm thick steel and 4 pieces of old 5 mm drills. That steel is very hard and when not too long , will not bend or break:
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(Or you can buy the excellent Hill Engineering tool )

A welded 19mm nut on the back gives enough grip, as the rings is screwed rather tight.
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Just rotate Counter Clock Wise and it will turn untill it comes off.
When it is off, you can simply tilt the cover inwards. It has a very large o-ring that seals the cover against the tank. Inspect for damage, but better renew.
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Then to ease the removal, remove the bolt that connects the 2 metal parts. That way it is easier to get the bucket out, as the bucket is the same size as the tank opening, but with an added bulge..
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When it is out, normally you will see 2 lines, supply and return , go from the cover to the central pump and the side of the bucket.
In my case those lines, as well as the rubber sleeve where the pump sits in, where completely deteriorated when the garage had gotten them out.
And in reality the supply hose was not connected anymore when I opened it up after their repair, so the pump could spin and pump all it wanted, but it all went back in the tank...
For the picture I reinstalled the line as it should have been....but as you can see, they only installed the supply line, and "forgot" the return...
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So in this case I had to make the return line myself. If yours is deteriorated, you will have to do the same. (or buy it at around 250 usd...)
The garage had bought a kit in Italy that comes with a pump, anti vibration pad, pump sleeve and a piece of fuel hose . (but the pump is a Bosch part used in other cars as well, just as the sleeve)
As this kit does not include a return hose nor a valve, the garage simply left it out...not good of course, warm starting problems waiting to happen.

When you take yours apart, the sleeve that holds the pump will have crumbled and fallen apart, and that debris cloggs the pump till it only gives like 20 psi pressure (creating a lean condition, and reduced power !) and then simply stops.
In my bucket there still was debris, the garage did not totally clean it out: (but you will normally find loads and loads more)
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But I was lucky that the filter part of the sleeve was still good, sometimes that is bad as well (smeared with black rubber smudge ), and that filter is around 100 usd or so a piece .

The 7mm inner diameter fuel hose of the kit was of NBR (fuel resistant type of rubber) quality, but also had EPDM written on it, which is not really fuel resistant. So not really a good hose in my opinion.
So I bought special in-tank full NBR 8 mm (inner diameter) pressure hose, and 5 mm (inner) clear non-pressure fuel hose for the return line.
Thankfully the garage had kept the valves and in the end where so good as to send them to me (we are not really on speaking terms anymore as they deny everything, they claim to have done a professional job...).

The non-pressure fuel hose needs to be warmed up with a heat gun (be careful, those things throw occasional sparks, and you do not want that near fuel/ fuel pump parts!), but then with a little lubricant slides over the green connector at the bottom, and over the valve connector and clips onto the side of the bucket. I could have taken a larger diameter, but that would not have fitted on the side of the bucket nor the surrounding of the green bottom connector.
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Now bolt it all together, be sure that the supply hose is not too long or too short , otherwise it will force the pump out of line. In my case it was exactly 20 cm. The length of the supply line is less important, with a curve it connects with the least elastic force.

Be sure the metal bolt is screwed tight, and now you can place it back in the tank.

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Something not shown in my pictures is the propeller formed anti-vibration pad that the bucket rests on in the tank. That often is very bad too. How mine originally where I do not know, now it has 2 new ones from the kit.

Be sure to grease the large O-ring, place it on the cover, and place the ring nut and screw it till it is really tight, 65 lbs/ft I read somewhere.
Grease the o-rings on the lines, so you can easily push them into the cover connections, and screw the 10 mm nut back on.

Then do nr 2!

Fill the tank up to a level above the lines and cover to look for leaks. If it is free of leaks, than start the car and look again. If all is well, you have pumps that will withstand E10 fuel for at least 5 years.

Personally I want to check the non-pressure hose after a year or so, when the fuel tank is near empty, so no draining is involved. Will take me then around 30 minutes or so to be sure all is still well.

 

Yes! That was what I was looking for, but could not find on google.
I was happy to find the special "in-tank" NBR rubber hose, being sold as especially for these purposes, but it still is rubber.
And the non-pressure hose will most likely harden or swell (or both...) in the years to come, that is why I wanted to have a look after a period of time.
But with that hose it will certainly hold longer, even if the original Ferrari hoses are comparible, but go bad as well (after 20 years).

 

Just a little note:
When you have removed the steel fuel lines that go under the car from the fuel filters to the flexible stainless lines, there is air in the system when they are placed back. (I removed them for cleaning and refurbishing)
You need to bleed the system by opening the schrader valve on the fuel rails on the engine. I connected the fuel pressure measuring kit, which has a pressure relieve tube to bleed it from air (normally fuel by the way).
When the pump is pumping, you will first hear some hissing at the relieve tube, till more and more air has been replaced by fuel, and then suddenly there is fuel pressure.
If you miss this step, chances are the pump will not really prime, and the pressure at the rail will remain zero.

 

Not sure about Kia, but the Bosch parts numbers might cross reference with it.
My pumps cross referenced with a Hyundai Pony. Bosch 0580453443
Be sure to get the right 4 bar pump, not the identical looking 3 bar pump.