2000+rpm hesitation... fuel pump?

[britlude]

hi all, merry xmas/happy new year....

as it's coming to the end of the xmas break, it seems my car has decided now is the ideal time to have a hiccup....

when cruising at lower revs, 1500-2000, if i gently accelerate , the car is hesitant, 'fluffy', and doesn't really want to do anything....

i suspect its fuel pump related as when i get to 4500 rpm it takes off like a scalded cat! i'm guessing it's associated with the fuel pump resistor.... i did think pump, but when that gets the full power post 4500(ish) rpm, there doesn't seem to be any lack of oomph, so the pump can keep up with full power at the lower half of the top end rev range....

tomorrow i shall try the fuel resistor bypass trick, just to see if that removes the problem and go from there.... check the resistor value and connection leads....

(i'll order a new fuel filter in the mean time and sort out a pressure gauge for the fuel system)

depending what the resistor reads on the meter, i may be looking at a new fuel pump to fit in the spring.... any recommendations as there's a variety of non-oem options... normal use, rather than race! (circa £100 for a pump, rather than £400 for the OEM pump and the bracket, when i already have the bracket seems excessive!)

[goldnsx]

Nothing more to add as I guess you're on the right track. Bad o2-sensors could result in a similar hesitation. Bypassing the resistor will tell you. There are plenty of options out there, some better, some less. They all need more current. So make sure you'll upgrade the OEM wiring if you don't go with an OEM pump. I prefer a Denso pump as it offers OEM quality but I didn't find just the pump. But I'll guess there should be a substitute. Whatever you do DO IT RIGHT (new gaskets...) as the labor is pretty timeconsuming...

[britlude]

found this comparison, discount the bosch as that's not in tank! http://realstreetperformance.com/Fue...ison-Test.html


and SOS... https://www.scienceofspeed.com/index...tting-kit.html

[Hagasan]

found this comparison, discount the bosch as that's not in tank! http://realstreetperformance.com/Fue...ison-Test.html


and SOS... https://www.scienceofspeed.com/index...tting-kit.html

Hi Jonathan, if you need a pump and want to go the Walboro route I have a brand new one I bought from SOS that I've never used. Still in packaging. Just let me know if you need/want it.. I'd have to check the box in the loft or my receipt as I can't remember if I bought the fitting kit they also sell

Cheers,

Gary

The reason I didn't use it is because of my SC kit. One of the Dutch guys had an issue because of the better flow rate which messed up his mapping. He also had an SC. I just erred on the side of caution and stuck to OEM as my setup was similar to his..

[goldnsx]

I also had the Walbro (from SoS) and had bad luck. I've bought two of them, one for me, one for my friend. Too bad I didn't give him the loud buzzer. His one was quiet while mine made noise to the extend that I went for the Denso Supra in the end which is very quiet and OEM quality. I've just had bad luck with the Walbro. With a very loud exhaust I might have left it in.

[NSXGB]

Rock Auto seem to stock a Denso pump.