help with fuel pressure on fd

[asp]

i got the car tuned,all was fine was pullin well in all gears,
took it easy most of the way home till i wanted to over take a few cars,5th gear went to boost it a bit got to 6k n it bogged down over fuelin,
tech edge went to r,i tryd to boost it a few more times got the same bogin down,that is what happend,
now this is my problem,
fuel pressure was 38psi,my regulator would not let me alter the pressure.so i bought a sard 1,now its gone down to 20psi also it will not alter,
so i got my old reg with stock pump rigd it up to 12v,it worked fine,alterd it 2 what ever i wanted,did the same with sard reg and walbro pump aslo worked fine.
stock or walbro pump in tank will not give me more than 20psi,i also checked what volts i was gettin at the pump 12.01 i seen wen ignition was turned on,
some thing else i tryed was measurein the fuel pressure at different places,fuel rail.fire wall.b4 the fillter all 20psi.all tryed with engine crankin over.,
 any body got any ideas

[MillSpeed]

So when you had the pump connected to an external power supply you were gettin 38 psi, but when it was connected to the 7\'s supply you were only gettin 20 psi even though you\'re still seeing 12v accross the pump? That\'s fookin weird. I wonder if the pump\'s getting the current it needs to work at full capacity. Does the ECU have any control over the pump load?

[asp]

external supply had 75psi at 1st as fpr was turned up a bit as i was not gettin ant pressure while it was on the 7,
Does the ECU have any control over the pump load?id like to no this.

maybe i could use 12v from the ignition,with bigger wire,

[MillSpeed]

Aye, that\'s an idea. I\'d run a direct feed from the battery through a relay operated by the ignition switch. I assume it\'s ok for the pump to be running continuously?

[MillSpeed]

Ah ha, just been doing some rummaging...looks like the fuel pump runs at two speeds. Apparently it\'s a common mod to run after-market pumps full speed all the time.

[asp]

il try a feed from the cars 12v n not the fuel pump 12v,cant c a problem with the pump runnin all the time,

any body id still like to no if any 1 has any thing else to say,
i dont like goin round the problem,if i can fix it i would rather fix it.

does any 1 no bout the ecu tellin the pump to lower the pressure?

[MillSpeed]

Yeah, there\'s a resistor that cuts the speed of the fuel pump at idle. I wonder if something\'s gone wrong with that? Just thought, would probably be a better ides to use the original fuel pump feed to trigger the relay.

[asp]

wen i fitted the 1st fpr i set it to 32 so on no vacume i had 40psi.
i cant even get 19 or 21psi now stays on 20 what ever i try,

so with the 2 speed thing,do away with that n do it straight of the 7s 12v,that i think will work,il do that then,
just a little iffy if some thing has broke,and im goin arround it,

[asp]

Just thought, would probably be a better ides to use the original fuel pump feed to trigger the relay.[/QUOTE]

now thats a go idea,every thing is in the boot then,
cheers fella

[MillSpeed]

I know what you mean mate, would defo still try to track down the problem.

[asp]

thing is if this works now,i probly 4get about the proper problem,

[antnicuk]

I have always run a seperate wire, bigger than the stock one to the pump with a new relay and an ignition feed to the relay to switch it.  This way you know the wires can support the current needed.

This is more important with an aftermarket pump.  

Never had a problem with the pump running full speed,  this was just mazda trying to stop the car running rich at idle and failing emissions.

[88GT-R]

Hi,
Ref Sard Regulator...They are adjustable. I had a similar problem when i installed mine for the first time. Where the vaccum nipple is, below that are two nuts. Loosen the upper nut, and adjust the static pressure to about 38psi, using the lower nut. Which one do you have? Does it have a label on it showing 200kpa-800kpa?

John

[asp]

its the 200kpa-800kpa fpr,if u read my 1st post idid say i could alter the pressure while it was connected to 12v but not the cars 12v,cheers for replyin thou the nuts on mine r the other way round lockin nut is at the bottom n adjuster is top nut

2day i pulled the tape off the wires that go to the pump,to check them.found that the hole wire loom was twisted round n round.the pump wires had fused together for about 2"
iv fitted a relay straight of the battery now and all works well,
cheers for the replys,
 new fuel pressure is 30psi at idle and 40psi at 0 vacuum
 does that look ok?

[Carl]

Hi Chris,
up the pressure at idle to around 38 to 40 psi just to be on the safe side.
Then carefully monitor the AF\'s when you get some boost and revs up.
Let me know how you get on.
Regards
Carl