Jump to content


Photo
- - - - -

Mpi Resistance Feeling


  • Please log in to reply
16 replies to this topic

#1 Classicmini63

Classicmini63

    Stage One Kit Fitted

  • Noobies
  • PipPipPip
  • 68 posts
  • Location: York

Posted 17 July 2018 - 07:54 AM

So I know my mpi needs a new pump because it’s kept blowing it’s fuse now and again, fixed this by putting a 15amp fuse in. So my mini has done this ever since I rebuilt the engine, basically I’ll be doing say 60 in 4th at around 3000rpm and the car will suddenly feel like there’s some resistance, almost as if the brakes are ever slightly on, and then a couple of seconds later all the power will come back at it will hold its own at 60 fine. And no I’m not driving up hills haha.
I’m thinking this is because of the stage 4 head and Cam etc, could this be a result of the ECU struggling to manage the overflow of fuel? Or is it simply the fuel pump dying?

Cheers

#2 Steve220

Steve220

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 4,877 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 17 July 2018 - 08:15 AM

So you fixed an electrical problem by over loading the wiring with a higher rated fuse? My first port of call is get the pump sorted ASAP!

#3 Classicmini63

Classicmini63

    Stage One Kit Fitted

  • Noobies
  • PipPipPip
  • 68 posts
  • Location: York

Posted 17 July 2018 - 08:18 AM

Yeah will do mate. It was just to get me home at the time and I drive it like once every two weeks but yeah either this weekend or next it will definitely be getting a new pump. Do you think a high performance pump would be worth it?

Cheers

#4 Steve220

Steve220

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 4,877 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 17 July 2018 - 09:34 AM

Nope

#5 Classicmini63

Classicmini63

    Stage One Kit Fitted

  • Noobies
  • PipPipPip
  • 68 posts
  • Location: York

Posted 17 July 2018 - 10:12 AM

Ok thanks. Why would it be no good?

#6 Steve220

Steve220

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 4,877 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 17 July 2018 - 10:17 AM

What do you think you'll achieve with it? To get any sort of benefit you'd need a mappable ecu or an adjustable fuel pressure regulator. A standard Mpi fuel pump will suffice. They work well for the turbo boys.

#7 Classicmini63

Classicmini63

    Stage One Kit Fitted

  • Noobies
  • PipPipPip
  • 68 posts
  • Location: York

Posted 17 July 2018 - 10:20 AM

Ok thank you, so would it be worth buying a standard pump and then perhaps the pressure regulator? Cheers

#8 Bat

Bat

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 903 posts
  • Location: Bermingum

Posted 17 July 2018 - 10:28 AM

Hi,

Just fit a standard pump, the more parts you change the less certain you will be if you still have a fault after changing the pump.

Nothing needs upgrading unless the engine has been modified from standard.

Cheers  :proud:



#9 Wiggy

Wiggy

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 1,036 posts
  • Location: Hampshire

Posted 17 July 2018 - 11:21 AM

Fuel filter been changed recently/ever?

I'd do that as well if you're going to change the pump.

#10 Classicmini63

Classicmini63

    Stage One Kit Fitted

  • Noobies
  • PipPipPip
  • 68 posts
  • Location: York

Posted 17 July 2018 - 11:45 AM

Yeah fuel filter gets changed probably every 6 months if not more. And the engine is an mpi with a stage 4 head, ported and polished inlet manifold, 52mm throttle body and SW5 fast road Cam.

#11 mini13

mini13

    Up Into Fourth

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 3,794 posts

Posted 17 July 2018 - 12:23 PM

get that pump changed pronto, and gent the proper fuse in there,

 

If the pump is killing the fuse then is probably going stiff or locking up momentarily( or there is a blockage as hinited above), which will be probably dropping the fuel pressure and causing your symptoms, upping fuse values can cause stress on the wiring and cause fire risks, obviosly i dont need to point out that this is especially the case when its related to a fuel system part.



#12 Steve220

Steve220

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 4,877 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 17 July 2018 - 04:27 PM

The throttle body won't be helping. Get back to the OEM one.

#13 Wiggy

Wiggy

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 1,036 posts
  • Location: Hampshire

Posted 18 July 2018 - 12:45 AM

The throttle body won't be helping. Get back to the OEM one.



Why's that? There's probably negligible benefits, but I can't see it being the problem, personally.

#14 Steve220

Steve220

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 4,877 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 18 July 2018 - 07:06 AM

The throttle body won't be helping. Get back to the OEM one.



Why's that? There's probably negligible benefits, but I can't see it being the problem, personally.

I said it wouldn't be helping, not that it's the causing factor. Larger throttle bodies don't necessarily mean more power or better response. There are a fair few articles on car forums about it. It gets a bit more pertinent when running boosted applications, but on nasp it appears to be more of a balance of Air velocity. I can't remember off the top of my head as I haven't have caffeine yet, but isn't the upgraded throttle body for the Mpi, 48mm?

Edited by Steve220, 18 July 2018 - 07:08 AM.


#15 viz139

viz139

    Super Mini Mad

  • Members
  • PipPipPipPipPipPip
  • 563 posts
  • Location: Ireland
  • Local Club: Irish Mini Owners Club

Posted 19 July 2018 - 08:32 AM

The fuel pump blowing standard fuse but running "OK" on higher fuse means either a faulty pump ( low fuel  pressure) or pump having to work too hard ( restricted fuel flow). Is the fuel filter your changing the standard one on the subframe or an additional one in the engine bay? Can anybody confirm if the MPi tank pickup has a gause filter like early tanks? Check pipes and hoses for kinks.






1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users