14 replies to this topic

[Fossy313]

hi guys,

 

wanted to put the PBV on my mini after the rebuild and was wondering what fuel pressure anyone is running out, Haynes manual says 1.0-1.3 bar, but I have read on different areas that people have got theirs on 2.4-2.6 bar at idle and i'm wondering if anyone knows actual facts?

 

cheers

 

Craig

[Guess-Works.com]

MPi's run at about 3 bar, spi's approx 1 bar.

[Fossy313]

Cheers john checking that's at idle yes?

[FlyingScot]

System pressure for MPi as John says 3.0 bar +-0.2 bar at idle (source Rover Workshop Manual RCL 0193)

FS

Edited by FlyingScot, 18 May 2015 - 03:55 PM.

[Fossy313]

scot cheers mate, I think im gonna put the PBV, I have a feeling the reason my mpi takes longer to crank is the current fuel pressure regulator that's on there at the moment.

Edited by Fossy313, 27 May 2015 - 09:37 AM.

[tmsmini]

The pressure should be the same in the rail even above idle. There is nothing to regulate the fuel pump to a higher or lower pressure except the pressure regulator, excess is returned.

 

I have been wondering about this as well as there have been times when it has taken a few seconds longer to get started. I wondered if it was the regulator or pump causing the problem.

 

The worst time was in 40 degrees C and after 4-5 hours of driving. It took 20-30 seconds before catching. Now it is every 15-20 th start, it may take 10-15 seconds to get going.

[Steve220]

The regulator is based on the flow rate of the pump. If the pump gets tired and isn't as powerful, and the flow reduces, then the fuel pressure will drop.

 

If the car is struggling to start, then i wouldn't necessarily start with the fuel, look at the spark. Reason being as if there was a slight reduction in fuel pressure, it would still fire or splutter.

[Fossy313]

Well she's dedinantly getting good spark, and if it's run for a bit then a quickly pop into the shop and jump in the car it fires up straight away because it's warm or my reasoning is pressure is there, however left over night it takes a few cranks to go,

Which is why I'm thinking fuel pressure?

Could try the next spark plug up but how do I find what the next one is ? bPR6ES

[Steve220]

What are you leads like? Could the coil pack be tired?

[Fossy313]

Coil pack could be tired I suppose but once again it's a case of another £50-100 that is a guess....I'm doing a rebuild so if it's the same after I will look at the coil pack and leads.

[Fast Ivan]

The coils on the mpi normally start to fail when they are hot, or at least that's normally when the problems become evident.
But you could test the coils primary and secondary resistance to help diagnoses

[Fossy313]

How would I do that??

[Fast Ivan]

I'll send you a guide Craig

[Fossy313]

Cheers mate

[Bobbins]

MPi's run at about 3 bar, spi's approx 1 bar.

Is 1 bar pressure in the Spi setup considered to be ‘low pressure’ in terms of appropriate fuel lines?