Fuel sender/pump unit problem

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RatSkin
Joined: Sat 07 Mar, 2009 17:09
Posts: 25

  Z3 roadster 1.9
Location: Villach

Fuel sender/pump unit problem

Post by RatSkin » Tue 12 Jul, 2016 15:27

Hi All. I have a fuel sender/pump problem and at the moment have not a scooby how to fix – so can anyone assist?

Almost straight after having a new front pipe installed, and then driving home, the fuel gauge just dropped, slowly, down to nothing.

So, no fuel gauge. So I'm now filing up and making sure the trip meter is set to zero. But what also happens is that, on a full tank, for the first 50 odd mile or more I get intermittent fuel starvation. After the 50 or so miles, she runs fine, except no fuel gauge.

I have Installed a second hand fuel pump/sender unit. But to my surprise the same two faults exist (suppose it could be another duff unit – but unlikely?). The new sender did register at first (only for a few miles though) at just above the area where the red light comes on (there was a full tank of fuel). But then it slowly went down to nothing – as before.

So I'm bemused – and would anyone have some ideas on the poss causes?

Cheers

David

Vic-Z3
Joined: Fri 11 Jun, 2010 20:28
Posts: 915

  Z3 roadster 2.2i
Location: Redditch
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Re: Fuel sender/pump unit problem

Post by Vic-Z3 » Tue 12 Jul, 2016 19:10

Fuel starvation ......... Check the massive fuel filter.
Fit a new one if it is old ...

https://www.youtube.com/watch?v=mnmfI3XIaAU

No more advise from me.
Wait for a guru to turn up ...... :)
----------------- BMW Z3 Das Beste Auto -----------------

Mein altes Auto riecht nach Nudeln, hat dieses Auto eine Wurst Geruch.

RatSkin
Joined: Sat 07 Mar, 2009 17:09
Posts: 25

  Z3 roadster 1.9
Location: Villach

Re: Fuel sender/pump unit problem

Post by RatSkin » Tue 12 Jul, 2016 19:23

hey it didn't cross mind about the fuel filter - i'll investigate - while i wait.... cheers

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Brian H
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Joined: Tue 16 Dec, 2008 19:55
Posts: 2502

  Z3 roadster 3.0i

Re: Fuel sender/pump unit problem

Post by Brian H » Tue 12 Jul, 2016 19:56

What caused you to have a new front pipe fitted?
Vic-Z3 wrote:Fuel starvation ......... Check the massive fuel filter.
Fit a new one if it is old ...

https://www.youtube.com/watch?v=mnmfI3XIaAU

No more advise from me.
Wait for a guru to turn up ...... :)
Good call about the fuel filter, the date is usually stamped on the filter so you can easily see if/when it has been changed

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g8jka
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Joined: Sun 18 Apr, 2010 22:16
Posts: 1145

  Z3 roadster 2.8
Location: Telford

Re: Fuel sender/pump unit problem

Post by g8jka » Tue 12 Jul, 2016 20:07

Just changed mine at the weekend, date stamped on it was 2007 so it was overdue a new one!
2000 BMW Z3 2.8 Titanium Silver Roadster with too many mods to list :-D :drive
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RatSkin
Joined: Sat 07 Mar, 2009 17:09
Posts: 25

  Z3 roadster 1.9
Location: Villach

Re: Fuel sender/pump unit problem

Post by RatSkin » Tue 12 Jul, 2016 21:55

New front pipe as it had split and blowing like a goodun! New lamber sensor as threads stripped. They also wanted to take off the manifold to remove knackered studs, but I said heat and hit! They came out sweet. A manifold off would have cost that little bit to much,
Anyway it's very likely that the fuel filter has not been replaced in many a year so at the very least it's a good thing to do. One is on order!
Then we'll see what happens.

NZ00Z3
Joined: Thu 23 Jun, 2016 02:26
Posts: 58

  Z3 roadster 3.0i

Re: Fuel sender/pump unit problem

Post by NZ00Z3 » Thu 14 Jul, 2016 10:28

Check out the carbon canister venting system. If its blocked you could be pulling a vacuum on the petrol tank. The area where the fuel gauge sender float moves is narrow. Any vacuum can cause the float to stick. If you have the pump unit out again, inspect the inside of the tank for scraping marks from the float.

What's the carbon canister? its a round canister, side mounted under the petrol tank on the left hand side, just in front of rear the sub-frame. There is a breather tube that goes under the sub-frame and up to a clip on the slide of the tank.

woodsta888
Joined: Wed 25 May, 2011 10:26
Posts: 25

  Z3 roadster 2.0
Location: Exmouth

Re: Fuel sender/pump unit problem

Post by woodsta888 » Thu 14 Jul, 2016 12:00

I had this, £400 later at the indy. Indy with all the gear no idea. It broke down again at home after filling with fuel. Wouldnt even come and pick the car up as it wouldnt start. In the end I got INPA and worked it out to be the switch before the carbon canister (Vent solenoid?). Cost £10 for 2nd hand one off ebay. TO test remove the one on the car and apply 12v to it, it should click if working. Mine started intermittently then failed totally.

When you get the symptoms of rough running and take the fuel cap off. Massive rush of air?

So if you live in the Southwest don't use Paddock motors. Awful.

RatSkin
Joined: Sat 07 Mar, 2009 17:09
Posts: 25

  Z3 roadster 1.9
Location: Villach

Re: Fuel sender/pump unit problem

Post by RatSkin » Fri 15 Jul, 2016 12:31

Great advice! thanks - i will look at the Carbon canister as i do get quite a vacuum - next week i will have my van back on the road and that will give me time to get this little inconvenience sorted.
Thanks again to all! (in the event it gets sorted :)
David

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