Fuel Pump issue

[ak1234]

has anyone had any issue with your fuel pump when your car sits for ling periods of time ... this will be the second time the fuel pump has become stuck and will not work ... the cause has to be the fuel we are getting in the usa ... last time the pump had some white powdery stuff ... my boss 302 mustang had the same issue ... I wonder if i could blow some air thru from the fuel line in the engine compartment to try to dislodge it ?
   
   Ron

[Superarnie Mk2]

Hi Ron, is your fuel pump electrical or mechanical? I have an electric pump fitted. It is a new Aeromotive A750 and is located close to the differential. I have only run my new engine in total for about 1/2 an hour but my pump has suddenly stopped working. I believe the pump is cooled by the fuel that travels through it so I wondered if there had been fuel starvation and it may have overheated or maybe suffered from cavitation issues. Another thing I have considered is that the fuel pump is gravity fed from the tank but the drop from the tank to the pump inlet is negligible so wondered if that may be an issue. I have since given it a gentle knock with a mallet and the pump kicked back into life, so I'm not sure what the issue may have been. I would be interested to find out if anyone else has had any similar problems. I'm not expert Ron, but could the white powdery stuff be corrosion, you often find aluminium materials corroding in that way. Sorry I can't offer further advice.
   Gary

[Rob.Hendriks]

Also have the A750 pump installed and it works very well, even after being left for extended periods.
   It would seem that there are other issues here: as mentioned white powder suggests alloy corrosion, if this is finding its way into the fuel pump then one must suspect the tank is corroded or alloy components within the pump are corroding, either way a full investigation of the fuel system would be advisable
   The A750 pump must is gravity fed and should be at least 4" below the tank outlet. The outlet and feed line should be a minimum of AN-8, preferably AN-10. If the pump is sticking after sitting, it would suggest that there is perhaps some corrosion, have you checked for water in your fuel? The pumps run on very close tolerances so they recommend a 10 micron full flow pre-filter to prevent any foreign objects getting to the pump and jamming the internals, which could also be an issue

[Superarnie Mk2]

Hi Rob. Thanks for the advice, my fuel supply hoses are correct and I have the correct filters before and after the pump. I'd be interested to know where you have mounted your pump. I think though with the mK4s the fuel tank is mounted high up behind the rear cockpit bulkhead so attaining a 4 inch drop, I'd guess was quite straight forward. On my car th tank is mounted low in the boot so I am having difficulty with that drop. I suspect that may be my problem though.

[Rob.Hendriks]

Gary
   The feed diameter and drop are very important.
   Given the size of the pump and the filter assembly I had no option but to mount mine in the boot (see picture below), the only other locations that could be considered were at the base of bulkhead behind the seats i.e. just forward of the lower A-arms (very cramped) and on the outside of the spare tyre well e.g. have the pre-filter and pump along the passengers side and the post-filter and regulator/bypass along the drivers side, with a braided hose running around the rear connecting the two
   If your filtration is fine then I would still suspect corrosion is causing the pump to stick, or electrical contacts
   
   

[Superarnie Mk2]

Hi Rob, thanks for the info and image. The trough underneath where your fuel pump is, is where my tank is unfortunately. I have no drop from the fuel outlet from my tank to the pump. If I was to work out some sort of bracket to mount the pump lower, the ground clearance would be very little. I'm struggling to think of a solution. I'd be interested to know if any lightweight owner has an electric pump and if so where it is mounted as I suspect their tank will be mounted in a similar position to my own.
   Regards
   Gary

[Rob.Hendriks]

Gary
   Are you running injection or carbs? the A750 is a 45psi pump for EFI and the drop to feed it is critical, as is the supply diameter. An alternative should it be possible would be to use an in-tank pump
   https://www.aeromotiveinc.com/product-category/stealth-fuel-systems/

[westcott]

In a former car i had the tank hanging below the trunk as on 60s cobras or MK IV Lightweights. I cutted a hole in top of the tank, installed a Tank service plate and frame and mounted the intank pump to the plate.
   Together with some small sump walls around the pump inlet it worked fine for all kind of EFI or carb.

[Superarnie Mk2]

Thanks guys for your inputs. I have since removed my Aeromotive pump and stripped it down to find one of the two magnets which surround the motor winding had broken off and attracted itself firmly onto the windings! The pump is Knackered!. I am unsure if it is as a result of a manufacturing fault or an inherent problem with my fuel supply. I have ordered a new Bosch 044 pump which I have read good reviews of. I have turned my pump mounting bracket upside down which will drop the pump by about 2 inches below the tank. The pump pre filter bracket will be modified this week to place it below the tank as well. I'll keep you posted!

[Rob.Hendriks]

Bosch 044 is a good pump if you get a genuine one... 90% of them are Chinese copies
   The guys at Aeromotive are very helpful, should you wish to go back to them contact
   
   Brett Clow
   Tech Director
   Aeromotive, Inc.
   913-647-7300  Ext. 109
   tech@aeromotiveinc.com

[Superarnie Mk2]

Thanks Rob, I will do.
   Regards
   Gary