Fuel pump recommendations

[oldskewel]

Originally Posted by terminx

I can confirm that the TI Automotive pump is what came in the box when I bought this on Amazon: https://smile.amazon.com/gp/product/B00PQXAWQI

I got lucky and found one open box on Amazon Warehouse Deals for $109. Guessing somebody bought it and thought they were getting the whole assembly, or couldn't figure out how to get the old pump out of their existing assembly without breaking it.

... or maybe they were hoping to get a Bosch, and thought they were getting a lesser brand with TI Automotive. I've also had good luck with great deals from Amazon Warehouse Deals. Usually a brand new item in a damaged box for 40% off.

[andrewwynn]

I couldn't find my tool I made for taking off the fuel pump "nut". So I came up with a very easy solution that people should use. I clamped two separate vice grips on to the little nubbins and used a quarter inch Drive extension as a handle between the jaws and it twisted right off

[itscoo2pyopants]

^ I used a flat head screw driver and tapped it loose with a mallet.

[80stech]

That's a good idea! Did find that you needed to replace the seal or could it be used again? How hard is it to check the jet pump o-ring from that side?

[terminx]

You're advised to replace it, but I reused mine because it seemed entirely undamaged and wasn't dry or brittle in any way.

Originally Posted by oldskewel

... or maybe they were hoping to get a Bosch, and thought they were getting a lesser brand with TI Automotive.

Man, their loss if that's the case! TI Automotive fuel pumps have been around for decades under the name "Walbro". I was thrown off a bit myself at first but a little bit of research on what was actually in the box cleared it up. It seems like a quality part.

[andrewwynn]

Originally Posted by 80stech

That's a good idea! Did find that you needed to replace the seal or could it be used again? How hard is it to check the jet pump o-ring from that side?

After 17 years both the seals on both our X5s were in perfect condition and I reused them as needed. I think the new pump came with a new seal so I have 1 of 4 replaced.

I wet the seal with gas so it will slide in nicely and I rotate the seal around in the tank hole to ensure its seated perfectly.

It's a very tight fit probably takes 30-40# of force to install the pump/sender unit.

Don't make the mistake of trying to put the seal on the sender unit first. The seal will often come out with the unit tricking you into thinking that you should put the seal onto the sender before installing into the tank: that will lead to A LOT of frustration.

The first couple times I used some clean engine oil to lubricate the seal but gas works fine. The tiny amount on the outside of the seal will evaporate quickly and is outside the enclosed people part of the cars envelope.

I discovered my siphon pump was not working properly last night and rebuilt my siphon jet pump.

Siphon pump DIY repair

https://r.tapatalk.com/shareLink?sha...4&share_type=t

Very detailed DIY "cookbook" on the process to rebuild a leaking siphon pump (this will work on any similar BMW siphon jet).

I'd be willing to bet a majority of x5 that have 150,000 miles with an original siphon pump have this failure to some extent.

It's a flawed design; the joint with the o-ring is held together from 4-6 cm away! It will be at a 5° angle by the time the failure is discovered.

Both our x5s had the exact failure.


Mine


Wife's

As you can see: identical failure.

There is a clear design flaw. The joint with the o-ring is held together not symmetrically around the o-ring as it should be, rather it's held from 4-6cm away offset to the side.

The pressure causes the joint to twist and eventually the o-ring can pop out of the groove and a huge percentage of the gas sprays out into the tank and no longer pulls the gas from the left to right side of the tank.

It's such a bad design and it's a relatively easy fix that I would as preventive maintenance replace the o-ring seal and re-work the "useless seal" on any BMW car / truck that uses this style of siphon jet.

A simple hose clamp around the two fittings would probably prevent the problem before it happens.

I can't imagine how many $100s of 1000s have been tossed away to dealers and indys who have replaced the entire siphon jet and sending unit simply because the o-ring failed.

[andrewwynn]

Originally Posted by 80stech;

How hard is it to check the jet pump o-ring from that side?

I'm not sure which side you are asking about.

With an inspection camera or a dental mirror you could check for the siphon jet failure from the right side. Actually even without, as long as the tank has enough gas.

If your right side reads over 2-3L, then the two sides are flooded over the hump in the middle.

If you have the right side open enough to see inside and turn the key to on (not start no need), if the siphon jet is leaking it will cause all kinds of chaos to the surface of the fuel.

If the siphon seals are solid, you should only see disturbance coming from under the surface on the right side.

It's probably safer to check from the right side, as you can tell from my crazy video where my iPhone got sprayed by gas, you'd avoid that completely by investigating from the right tank opening.

[80stech]

Thanks! Awesome post! Do you have a size/part number for the o-ring?

[andrewwynn]

Unfortunately I don't. The one I used was way undersized diameter with a larger than spec cross section (I wanted it to be very tight so it would be impossible to jump the track again). If the ID of the groove is 25mm the o-ring I used was at most 20 but instead of 1.5mm cs I had one that was 2.0. When stretched out the cs shrinks so it worked out great. Sorry I didn't have my caliper in the house where I did the o-ring so I didn't think to get an exact size.

When using an undersized o-ring like that, it's important to run a smooth tool around the entire o-ring once or twice to evenly distribute the o-ring so it's not bunched up somewhere.

[80stech]

It almost looks like the groove would be wide enough for a backup ring ??