Fuel pressure on tickover-Urgent please

[Davey]

I need to know what the fuel pressure should be on tickover, with no vacum (if that makes sense) :?
Cheers, Dave

 

[Davey]

Found it somwehere else, it should be 2.45bar.
Mines 3.2, i guess thats why my car's a bit rich :?
Anyone know anything about fuel pressure regulators :?:

 

[AJ4]

I thought it was supposed to be 3bar with no vacuum :?:

 

[zia]

it will depend on the fuel pump.big fuel pump generally increase the fuel pressure even though you have stock regulator.

zia

 

[BFMurphy]

my pressure is just under 4 bar at idle and rises to just under 4.5 bar when i rev it.

 

[Davey]

Now I'm really confused :?
The manual http://www.mummachummas.co.uk/gtir/IDLE_ADJUSTMENT.PDF say's 2.45, and I thought it should drop when you rev it, because you are letting more fuel into the inlet manifold.
My 'R will hardly start because it's so rich, but if you remove the fuel pump relay, it starts perfectly, indicating too high fuel pressure?

 

[zia]

do you have stock regulator? has it been squashed? are you using stock feul pipe work?



zia

 

[Davey]

Everything is standard, fuel wise, I presume the pump is standard as well.
Pipe work looks OK.

 

[MarkTurbo]

I know you werent getting any fault codes but maybe the ecu has gone mental and is just chucking loads of fuel in.

I wouldnt have thought having higher fuel pressure at idle would make it run like that, the amount of fuel going in is controlled by the ecu telling the injectors how much to put in surely :?

It might be worth trying another ecu just to make sure it isnt that.

 

[zia]

if you remove the vaccum hose does the pressue increase? how have you tapped the guage in?

zia

 

[mattygti-r]

ive a DEFI BF fuel pressure guage good bit of kit from memory its around just under 3 on tick over and on 1bar over 4

 

[Davey]

I wouldnt have thought having higher fuel pressure at idle would make it run like that, the amount of fuel going in is controlled by the ecu telling the injectors how much to put in surely

I think the idea is, that although the ecu controls the pulse of the injector (frequency and length of opening?), if you have more pressure in the fuel line, then more fuel will be injected, even though the injectors are doing the same thing they were before (if that makes sense). It's like opening a tap, if you have more water pressure, more water will come out, even though the tap is open the same amount.

Trying another ecu sounds like a good idea, dunno who's got one round here though, might have to have a word with Ben

if you remove the vaccum hose does the pressue increase? how have you tapped the guage in?

I didnt do it myself, cos i havent got a gauge, my mechanic did it, dont know what happens with the vaccum on/off.

its around just under 3 on tick over and on 1bar over 4

Still dont understand that, I would have thought fuel pressure should dercrease when more fuel is called for, thats why you need a higher capacity pump when you run more boost.
I hate being stupid :?

 

[mattygti-r]

heres my guages with just the keys in the ignition hence hte "warning" on the defis

 

[Keira]

Still dont understand that, I would have thought fuel pressure should dercrease when more fuel is called for, thats why you need a higher capacity pump when you run more boost.
I hate being stupid :?

the fpr is rising rate, for every increase in boost the fuel pressure increases with it

 

[Davey]

Well, why didnt someone say so before!
Nice looking dials Matty, bet they werent cheap :?

 

[mattygti-r]

edited for kieron :roll:

 

[Keira]

how many more times are you going to pointlessly post a picture of your gauges then ??? :lol:

 

[MarkTurbo]

I wouldnt have thought having higher fuel pressure at idle would make it run like that, the amount of fuel going in is controlled by the ecu telling the injectors how much to put in surely

I think the idea is, that although the ecu controls the pulse of the injector (frequency and length of opening?), if you have more pressure in the fuel line, then more fuel will be injected, even though the injectors are doing the same thing they were before (if that makes sense). It's like opening a tap, if you have more water pressure, more water will come out, even though the tap is open the same amount.

What i meant to say was having higher fuel pressure wouldnt chuck so much extra fuel in that the car wont run

I'm just crap at explaining things :lol:

 

[Keira]

edited for kieron :roll:

thank you :lol: