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.

[britlude]

made myself up a jumper link today and took it for a drive... unfortunately it's currently an intermittent problem so not sure it was actually doing it today..... i shall have to take it for a longer drive tomorrow...

in the mean time i did give the inlet a quick clean (wasn't too bad)
WP_20171230_12_30_18_Pro by jon sutherland, on Flickr

and cleaned the air filter (K&N) and re-oiled it....
WP_20171230_12_23_36_Pro by jon sutherland, on Flickr

...odd that it had a clear bit.... still, it's a K&N, at least i have the option to clean it!!!

ordered myself a fuel pressure gauge/kit to check the pump health!

]

[britlude]

took it out today and drove until it started to stutter/fluff..... stopped and put the relay jumper widget in and continued... the same piece(s) of road were fine, no fluttering.... so just to double check I swapped it back to the resistor and set off on the same roads...... it was ok.....

so....... is the resistor having issues when it gets hot (which it was) and after the swap out had cooled, and once swapped back hadn't had enough time to get back up to faulty temp?? i'll order a new resistor anyway.....

i also found the recent wet weather had caused the car to get damp/steam up again... tracked it down to the thin rubber seal/edge/trim between the moulding that goes over the door and the roof... the one that SOS charge $40 for, but then want $53 to post it on the slow boat, when I know it'll fit into a big jiffy bag! and it's not actually the right one for over-the-top fitment.... https://www.scienceofspeed.com/index...x-1991-05.html

when the rain is sufficient to drench the roof, the water can get under this seal, then onwards getting behind the rubber on the b post... then down the door pillar...

new mouldings seem to be discontinued, but are way over priced! unless there's good s/h hands out there at a reasonable number!! not found any so far!

i've also sourced some waterproof foam that goes inside the over-door moulding... if the moulding have ever been off, it'll probably be useless anyway (same sort of deal as the rear light seals)

i'll probably have to order the resistor from SOS to try and dilute the shipping, but of course it's sunday and B/H, they don't have it listed on the site, so can't get things underway.

[Hagasan]

Jonathan, why don't you just get the parts from Marc Perez.. Sure it'll be cheaper for both the part and shipping? It'll cost what you say it costs if you get my meaning..

[britlude]

SOS had the rubber extrusion made, so can't get it anywhere else.. tho it has to be modded to work where i want them....but i'm working on it! i've ordered from Marc before, i know what you mean!

i've also found a place over here with VERY competitive pricing... just waiting for confirmation, and to find out what the catches are!!!




does anyone know what the resistance should be of a good resistor?? can't find any mention anywhere