[urq] Fw: I Eat Fuel Pumps - What is Going On

[Patrick Carlier]

----- Original Message ----- 
From: "Patrick Carlier" <p.carlier at pandora.be>
To: "AF" <afinn1 at gmail.com>
Sent: Tuesday, February 17, 2015 10:52 AM
Subject: Re: [urq] I Eat Fuel Pumps - What is Going On


> Usually these pumps have an internal bypass wich should take care of
> excess flow and / or pressure .
>
> I do agree that if the pump flows to much for the regulator to handle , 
> you'll end up
> withto much much presssure on the fuel rail .
> But that's an other issue , and it should not harm the pump in any way .
>
> Fuel pumps really really hate low pressure on the  intake side .
> It'll kill a pump in "no time " . Btdt got the T-shirt , two of them 
> actually .
>
> One cause is a restriction between the fuel and the pump .
> Could be rust in the tank , could be a filter , a flexible hose .... 
> anything .
> Pull the hose from the fuel pump , and check if you have a decent steady 
> flow .
> No hickups , no hesitations should be seen .
>
> A second possible cause is tank ventilation .
> If somegow you don't get air in the tank , the pump will suck it vacuum .
> I think that is what you're hearing when you say you have a lot of 
> pressure in the tank .
> So try this :  , fill the tank only halfway , and do some serious runs 
> with the filler cap removed  .
> I bet it'll make a difference .
>
> Best of luck
> Pat
>
>
>
>
> ----- Original Message ----- 
> From: "AF" <afinn1 at gmail.com>
> To: "urq" <urq at audifans.com>
> Sent: Tuesday, February 17, 2015 5:13 AM
> Subject: Re: [urq] I Eat Fuel Pumps - What is Going On
>
>
>>I just found this on a bosch website. Maybe I need to measure my fuel
>> pressure. Maybe I don't need an 044 Racing Pump?
>>
>> *Fuel pump → fuel pressure regulator compatibility*
>>
>> Whilst it has become common practice to fit high flow competition type 
>> fuel
>> pumps to standard road cars, it is important to consider whether other
>> system components are suited to this modification. The function of the 
>> fuel
>> pressure regulator is to maintain system operating pressure at a preset
>> factory value. This regulator can only do this within its’ nominated 
>> return
>> flow specification, an abnormally high fuel flow may exceed the 
>> regulators
>> ability to control fuel pressure as it cannot recirculate the fuel back 
>> to
>> the fuel tank quickly enough. This situation will result in an abnormally
>> high fuel pressure and/or erratic control.
>>
>> Andrew Finney
>>
>> 1985 UrQ
>>
>> On Mon, Feb 16, 2015 at 8:09 PM, AF <afinn1 at gmail.com> wrote:
>>
>>> I really need the collective wisdom of what's left of the list... a 
>>> little
>>> background first.
>>>
>>> when I rebuilt the UrQ I stupidly did not cut open the tank. I mean the
>>> car had sat outside for 15 years. I should have known better. I wen 
>>> through
>>> 3 fuel pumps, then I switched to the 034 Motorsport 1 litre sump can and
>>> 040 motorsport in-tank pump with a low pressure feeder pump. I went 
>>> through
>>> 2 of those 040 series Bosch pumps before I realized the tank was FULL of
>>> crap and killing pumps. I did everything wrong, I used a 10 micron 
>>> pre-pump
>>> filter which was too fine, I tried the original filter-like plastic
>>> pre-pump thing, but last week I finally decided I knew the solution and
>>> stripped all the plumbing out and went back to an aeromotive 100 micro
>>> pre-pump filter, a bosch 044 racing pump and at Patrick's suggestion I 
>>> put
>>> a pressure damper on the outlet of the pump. I cleaned and POR15'd the
>>> tank. I cut the filter sock completely off the intake in the tank. I
>>> thought this was the last time I had to mess with the system.
>>>
>>> This weekend at the track, 70 degree day, the pump is buzzing like a 
>>> hive
>>> of bees and then either overheats or vapor locks after the last run of 
>>> the
>>> day. I had to wait for something to cool down before it would run. It 
>>> would
>>> start, run, then stumble and die. Lots of pressure in the tank when I
>>> opened the filler cap.
>>>
>>> Can anyone possibly tell me why this pump seems to be dying now after 6
>>> hours of use? What is happening that is killing it? I do have an 
>>> adjustable
>>> fuel pressure regulator and 034 tuned it to produce more fuel as I was
>>> running a little lean. Is this an issue of the pump flowing too much 
>>> fuel?
>>> It's a tuned ABZ V8 but these pumps should be good for 700 hp right? I 
>>> am
>>> truly at a loss.... Any help is appreciated.
>>>
>>> Andrew Finney
>>> 1985 UrQ V8
>>>
>> _______________________________________________
>> Audifans urq mailing list
>> Manage your list connection: http://www.audifans.com/mailman/listinfo/urq
>> http://www.audifans.com/kb/List_information
>>
>> Pictures/Polls/Database at: 
>> http://autos.groups.yahoo.com/group/urquattro/
>>
>>
>