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Blown Fuel Pump Fuse - Fixed.

lucasxdiniz

Active member
Northamptonshire
Hi all,

Recently I had a whole saga trying to fix a fuel leak I had - I replaced the fuel filter which solved the issue (more about this on my personal thread). This past weekend I went to Wales and had a lovely couple of days driving the car fairly hard there - about 500 miles since the fuel leak work. Yesterday while cruising up the Horseshoe Pass I pulled into a layby to let a few cars disappear for a clear run up and as I started to pull away the car shut down and wouldn't start. A lot of head scratching later and realising I couldn't hear the fuel pump priming, I checked the fuses and saw no #4 was blown. Replaced that and the car fired right up and power band was fine and engine felt happy.

Only sometimes while pulling away slowly from roundabouts, the car would bog down and die, but would still restart and more revs would get it going. Once going, no issues. I cut the day short and drove back home in England to be safe - 130 miles on the motorway and no issues then. After letting the car cool down and cleaning it to put in the garage, I started it up, it ran roughly (running out of fuel) and died. Checked the fuse and it was blown. Changed that, the car started and I was able to drive it into the garage normally. At the moment, it still starts up without issues.

Obviously I disrupted the wiring and fuel lines from the pump to the filter while doing the filter work, so I will be quadruple checking that. However, I'm fairly confident, all of that is fine and my fuel pump is probably on its last legs and getting stuck or something and drawing too much current and popping the fuse.

Has anyone replaced the fuel pump with an aftermarket unit such as a Walbro one? Would an S54/Z4M need to be remapped for it (my current assumption would be no due to the pressure regulator within the tank, but happy to be told otherwise).

I expect this will be yet another part BMW will not have in stock (if not discontinued all together) and the weather is nice, so I don't want to waste 4-12weeks waiting for parts!
 
Try
JC Racing
Simon Thorpe Motors in Grimsby
Wayne at Chip Wizards North Manchester ish

Between these 3 they will have an answer and maybe a spare pump

If it is the pump there is a lot of work to get to it so be sure it is faulty before you start at least one of the above will have live data to log the pump pressure
Wayne has a rolling road so it is easy to check at full load

Hope this helps
 
PDJ said:
Try
JC Racing
Simon Thorpe Motors in Grimsby
Wayne at Chip Wizards North Manchester ish

Between these 3 they will have an answer and maybe a spare pump

If it is the pump there is a lot of work to get to it so be sure it is faulty before you start at least one of the above will have live data to log the pump pressure
Wayne has a rolling road so it is easy to check at full load

Hope this helps

Thank you for all the suggestions. I will be calling some places to get quotes for parts, but won't be taking the far anywhere. Well familiar with getting access to the inside of the tank.
 
For posteriority:

The routing for the harness which supply the fuel pump from the EKP module runs alongside the diff-prop flange. This harness is secured by a clip which is bonded to the fuel tank. I believe that when I did the fuel filter replacement work which involved removing the harness from its clip, a small part of the clip broke and I did not notice. The clip secured the harness well enough to fool me during assembly but it must have come out of the clip when I was hooning in Wales, which allowed the harness to get chaffed by the prop-shaft until it reached bare Copper of the live wire and shorted to ground thus popping the fuel pump fuse.


This is an image before the harness was removed from the clip before I did a light restoration to the rear end over winter:

20240211_163510.jpg

Here's the stripped harness showing the live wire that got chaffed by the prop:

20240509_204132.jpg

And here's the repaired harness. It's noticeable that the corner of the clip is broken:

20240509_211155.jpg

You live and learn. Repair took me about 4hrs all in. Cost was nill since my work has an electrical department who let me dig through their spares bin and advised me on the best method to repair the harness in situ.
 
lucasxdiniz said:
aftermarket unit such as a Walbro one?

If you ever need one .

Take a look at this post https://www.zpost.com/forums/showthread.php?p=31185019#post31185019 . Reply 17 states a pump model .

and there is also a discussion about it here https://www.zpost.com/forums/showthread.php?t=1300971
 
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