what controls the fuel pump speed command from ecu?

[zen]

just done my supercharger install..ie test drive an hour ago..

now need to know what the ecu uses to control the fuel pump voltage.i know how it switches the resistor in and out,but what inputs does it montor to know when to alter fueling??

i ask as my adjustable fuel reg dont..connected it ok,but no change when i dissconect the vac /boost line to it,(on idle)..it may well be working fine (cant see the gauge once driving)..but am wondering if my fuel pump is up to it..

so..how does the ecu know when to up fueling?(ie switch out the resistor and hense work the fuel pump at max capacity)

thank you

 

[zen]

pk..its sta and airflow meter,rev input too..

 

[Bushwhacker]

If you have an adjustable fuel regulator, can't you just run the fuel pump seperately?

 

[4U2QUIK]

you can just run straight 12v. the factory regulator will bring the pressure to where it needs to be.

 

[cribbj]

Manifold pressure (vacuum) is your best indicator of engine load for the fuel pump ECU.

BTW, that's very odd that your FPR isn't changing the fuel pressure at idle. You should see 3 bar / 43 psi at idle without the hose connected, then it'll drop to about 35 psi with the hose connected. Check that it's doing that, and if not, then you need to sort it.

Either your FPR isn't working, or your hose is clogged. You can check the hose easily enough, just by feeling the end of it when you disconnect it. Then if it's OK, something's screwy with your FPR.

 

[sideshow]

normally toyota ecus change to higher voltage at 4000 rpm
so yours might be similar
anyway i always bypass the 2 speed pump as once u mod the motor u need it at hi voltage all the time
running fuel pump ecu is a pain and not many guys get them
so i just trigger the fuel pump to run batt voltage my own way and not worry what the engine ecu is trying to do

 

[zen]

sounds about right...

interestly the wide band a/f meter is giving good readings on the "iffy" fpr...still will change fuel pumpcrt to run 12v all the time anyway..it dont have a seperate ecu,the main ecu controls the fuel pump relay directly..

 

[sideshow]

what is yr ecu
did u wire up the crappy 2 speed fuel pump control
unless its a std car i never bother with it

 

[zen]

ecu is standard 1995 that came with engine (second gen)

i wired up everything,(including brake input etc...if doing a job do it properly,just like what you do..)only thing i didnt was speed sensor as car is old range rover and has mechanical type speedo..

yes i wired up crappy twin speed fuel pump..it does switch over,but i think it needs to go...

 

[sideshow]

heheh
speed sensor is probably more important than brake input
brake input is only needed when its auto

problem u get with the 2 speed pump thingys is its just another thing to fk up
and all it does it quieten pump
i dont think ive ever wired it up in over 1000 jobs hehehehe

its good to wire it all like std but it also has to be reliable
so less things to go wrong then less chances of breaking down
plus i dont have to wire it in so job takes 20 minutes less to do heheheheheheheh

 

[zen]

yes agree...

am going to fit speedo sensor,but will have to use the land rover item..found one that gives a pulse and allows the cable fitment in and out,so can still have mechanical speedo...and yes i know it controls a few things,ie fueling on decelleration..

as for reliability..well no crimps..solder,lots of extra fuses and relays..my car has only 3!!!!! fuses as standard...