What Affects Fuel Systems?

[markdem]

sometimes my stagea doesnt want to drive. ill put my foot flat and it'll sputter n pop without any power. ive checked around the engine for things like vac leaks and changed spark plugs. i think it might be something to do with fuel delivery. ive heard of some skylines dropping voltage to the fuel pump on idle to save fuel. perhaps the fuel system gets stuck in 'economy mode'?

id like to test the parts on the car that affect how much fuel the car gets. ive already thought about checking manifold pressure sensor and throttle position sensor and obviously rpm. can anybody think of anything else that would affect how much fuel the engine gets?

also, where is the fuel pressure sensor and how would i test it?

[QWK32]

Changed the fuel filter at all? It also could be a failing fuel pump, they are fairly cheap these days so it would be worth swapping out for a new one.

The dual voltage comes from the fuel pump control module. The ecu tells the FPCM when to run at the lower voltage, it is about 8 volts. It only does it at idle, I did a bit of testing in it out of interest. Ill pm you a little DIY PDF I made up on how to bypass it. What model stagea is yours? It's for a S2 but it might be the same as a S1.

Looks like you've pritty much covered most of the bases. The only other thing on the fuel system is the fuel pressure regulator, it's on the end of the fuel rail and should have a vac line going to it as well, if the vac line has popped off, or the reg is cactus, it will lean out under boost.

[markdem]

yeah man that PDF thingy you made would be awesome! the more info the better i have an s1 stagea with the an s2 engine - same as the r33 s2. cheers bru

[markdem]

i had a look over that PDF document. well explained and the diagrams and pics help a lot! awesome job man. and thanks for the help! ill test it out when i get some daylight to work with

[QWK32]

i had a look over that PDF document. well explained and the diagrams and pics help a lot! awesome job man. and thanks for the help! ill test it out when i get some daylight to work with

yeah i guess there won't be too much difference between the S1 & S2. i'd say the parts will be in roughly the same spot but the wire colours may be different. even if it doesn't fix the issue its another thing to cross of the list hey.

[markdem]

hey man i just did the mod. it was easy as - thanks to your instructions! they really helped get the job done quickly and more importantly; correctly! the car still needs more testing as it was an intermittent problem but i think i can already feel a difference in acceleration

thanks for your help bru