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Fuel pump presure??

Discussion in 'A3/S3 Forum (8L Chassis)' started by frank s3, Jun 12, 2013.

  1. frank s3
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    frank s3 Member

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    [Jun 12, 2013]
    Hiya guys,just wanted to know wot the fuel pump presure is and check if mines all good thanks frank
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 12, 2013]
    Fuel pressure should always be FPR + boost or in the case of idle and cruise FPR - vacuum... Assuming you have an S3 (from your username) then this should be a 3bar FPR... on idle it will be just under 3bar, on a std S3 it will be just under 4bar (0.8bar boost + 3bar of the FPR)

    Best way to check is using a fuel pressure gauge on a dyno but depending on what the year of your S3 is you can get an idea of how the pump is fairing by logging fuel blocks in VCDS...

    <tuffty/>
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  4. frank s3
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    frank s3 Member

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    [Jun 12, 2013]
    Yes it an s3 it 2002 and ive run one in line where the filter is i have a 4 bar fpr! I not long ago had my engine rebuilt and was piston rings i just want to make sure its fueling rite ready 4 maping as i have a revo stage 2 and may have got pinking when i get up to boost!
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  5. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 12, 2013]
    Don't need a 4bar FPR... bin it off...

    <tuffty/>
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  6. frank s3
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    frank s3 Member

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    [Jun 12, 2013]
    What diffrence will it make?as was told it would be better with a stage 2 i just want to be fueling enuff as ive had my engine rebuilt due to under fuleing and spent alot of time and money trying to get it rite.
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  7. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 12, 2013]
    4bar FPR puts more strain on the pump... there is no reason in the world to use one on a stage 2 tune... 3bar FPR and std injectors will be fine up to 280/290hp which tbh most cars these days don't make regardless... if you previous engine melted from lack of fuel pressure then a 4bar won't help... it will be the pump... assuming you haven't changed this already then that should be next on the list...

    Generic maps have had their day on our cars now... custom map to the condition of the engine is the better option... I wouldn't even get a map unless it was done on a dyno tbh as these engines are so variable generic maps are not really suitable

    <tuffty/>
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  8. frank s3
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    frank s3 Member

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    [Jun 12, 2013]
    I was just advised so went with it! I was thinking the pump was weak so was lookin for figures to check it b4 buying 1 guessing there pritty pricey! Im not sure if the pumps weak and is wot caused me to melt it, more inclined i had to much air! Ive been told by the fella who advised the 4 bar fpr that the pumps are usaly good and dont drop presure! Appreciateing ur help.
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  9. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 12, 2013]
    Pumps are getting old... have seen loads on the dyno clearly failing... wideband cars like yours compensate by ramping up the injector duty to meet the requested AFR by the map... once you are at a certain power level though it can only do so much and the injectors are essentially open all the time but pressure has dropped...

    Logging blocks 001, 002 and 031 with vcds will give you an idea... lambda control value in 001 will increase as this is the value of extra fuelling (in percent) the ecu is adding to bring actual fuelling inline with requested AFR.. if this is increasing as revs rise under WOT then the pumps not keeping up... 002 will show iinjector duty... anything much over 20 essentially means you are pretty much maxing them out... 031 is to keep an eye on AFR

    Bin the 4bar by the way... may have mentioned this before ;P

    <tuffty/>
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  10. frank s3
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    frank s3 Member

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    [Jun 12, 2013]
    I shall put the 3bar in this eve ;) Do you konw wheres best to get a pump from or run an inline one as a brand new 1 is 300ish from tps i would head over to badger 5 for a map but ive had so many problems that its a long drive to come home un maped
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  11. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 12, 2013]
    tbh the best one to go for is an OEM one... westy had issues with a pattern part IIRC...

    don't think it was 300 quid though... was a fair chunk of 200 though

    <tuffty/>
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  12. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Jun 13, 2013]
    I think you should not be taking this "fellas" advise dude

    REVO2 on k04 cars is not for 4bar regulators (only k03 cars is their stage 2 4bar)
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  13. frank s3
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    frank s3 Member

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    [Jun 18, 2013]
    Found a pump on euro car parts vdo is the brand is it better to go genuine or is aftermarket the same as?? Thanks again
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  14. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 18, 2013]
    I think VDO is an OEM supplier but I am sure Westy bought a VDO pump from GSF/ECP and it was just wrong... maybe ask him?

    <tuffty/>
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  15. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Jun 18, 2013]
    That wasn't me by I do remember the post. I'd learnt my lesson with the non OEM heater matrix and am now sworn to oath to only ever buy genuine vag parts now.
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  16. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 18, 2013]
    Ah... so many posts lol... no idea who it was then but at least I wasn't imagining it :D

    <tuffty/>
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  17. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Jun 18, 2013]
    For some reason I think it was Hoggy!
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  18. frank s3
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    frank s3 Member

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    [Jun 18, 2013]
    Thanks again ill try find out its just that theres about 70- 80pounds between them vag want 250ish and the vdo is 180 just want it all to be correct for maping :)
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