Fuel Pressure test results

[jj7]

After i made my own fuel pressure gauge,which total cost was around 12$, i tested my car`s fuel pressure and theses are the results:

Idle: 3bar (43.5 psi)
Rev.Engine: around 3.6bar (52.2 psi)
Static with engine off: around 2bar (29 psi)

per bentley,my car spec is 3.5bar, and from the results above,does the fuel system of my car seem normal?

Any input appreciated

PS: the test was done at the end of the fuel rail (return),front of the engine

TIA

jj

[Javier]

they all seem excessive and are useless, you should take the pressure at the incoming hose to the fuel rail (or even at the pump output in the trunk if your filter is new), but never in the return hose.

This link is applicable to M30 engine, think I recall that pressures for M50 a slightly higher, Winfred may help (or the Bentley as an alternative, I trust him the better).

http://www.bimmer.info/forum/showthread.php?p=15307#post15307

Javier

[winfred]

those numbers sound ok, do you have a running problem or are just playing with the car? the pressure will be lower at idle and other times of high vacuum due to the fuel pressure regulator

[Jon K]

Can you link to how or tell how you made the gauge?

[Bill R.]

the motor not the return, and as Winfred said his pressures seem normal or within the allowable ranges.





they all seem excessive and are useless, you should take the pressure at the incoming hose to the fuel rail (or even at the pump output in the trunk if your filter is new), but never in the return hose.

This link is applicable to M30 engine, think I recall that pressures for M50 a slightly higher, Winfred may help (or the Bentley as an alternative, I trust him the better).

http://www.bimmer.info/forum/showthread.php?p=15307#post15307

Javier

[jj7]

I truly appreciate the inputs,but before i carry on please correct when wrong i am still a begginer and learning from you guys,and each time i am given a hint or two it sticks and adds to my knowledge,as for some comments of mine they go as follows:

1- the link for making the pressure test gauge http://minimopar.knizefamily.net/quickfpg.html , this link is really nice and got some other info can be useful,the gauge i made is almost the same idea but simpler,i will try posting some pics of it.

2- the testing was carried out on the front side of the engine,where the fuel rail is closest to cylinder No.1,the fuel hose is coupled by a plastic clip,and joined with crank ventilation hose.(is it the return or supply)?

3- the car is running with a flat spot/hesitation at take off,and it gets worse when the A/C is on, the idle drops when A/C is turned on too.I was attempting to rule out the FUEL factor,since the injectors were recently serviced and tested,fuel filter new,a hose coming out of the tank was replaced after some cracks were found.At high speed nothing of the hesitation is noticed,nor the A/C makes any difference.

I hope i am on the right track here,yet,guidance is required :)

TIA

jj

[Bill R.]

of flow. The one you tapped into is the supply line and the other is the return linehttp://www.realoem.com/bmw/diagrams/q/77.png









I truly appreciate the inputs,but before i carry on please correct when wrong i am still a begginer and learning from you guys,and each time i am given a hint or two it sticks and adds to my knowledge,as for some comments of mine they go as follows:

1- the link for making the pressure test gauge http://minimopar.knizefamily.net/quickfpg.html , this link is really nice and got some other info can be useful,the gauge i made is almost the same idea but simpler,i will try posting some pics of it.

2- the testing was carried out on the front side of the engine,where the fuel rail is closest to cylinder No.1,the fuel hose is coupled by a plastic clip,and joined with crank ventilation hose.(is it the return or supply)?

3- the car is running with a flat spot/hesitation at take off,and it gets worse when the A/C is on, the idle drops when A/C is turned on too.I was attempting to rule out the FUEL factor,since the injectors were recently serviced and tested,fuel filter new,a hose coming out of the tank was replaced after some cracks were found.At high speed nothing of the hesitation is noticed,nor the A/C makes any difference.

I hope i am on the right track here,yet,guidance is required :)

TIA

jj

[Javier]

there was a clogged return hose, and never heard about that.

Javier