FC3S_Bat

Hello, i am looking to replace my fuel pump on my 1990 convertible. S5 6port. I was told car is running lean. I already cleaned all 4 fuel injectors (3 injectors were a bit dirty). Replaced spark plugs (replaced stock with iridium bur10....something. Higher heat rating.) And still struggles to start now and then. I have to keep pumping the accelerator for motor to start. So im moving on to the fuel pump, i read from RB that all 13b require 5psi to function better? Or at full capacity without leaning out on higher rpms. Which is also an issue. Up to 6k the car feels great and then slowly stops pushing power after 6.5k.
Should i just replace with an oem pump? Or does anyone recommend something better than oem.

nyt

iTrader: (1)

walbro 255 is a cheap and easy replacement.

Pete_89T2

iTrader: (4)

What makes you think it's running lean? Do you have a WBO2 hooked up to measure AFRs? When you say "Up to 6k the car feels great and then slowly stops pushing power after 6.5k", that sounds pretty normal for a stock S5 6 port NA that is still stock -- power does start to drop off > 6K. The difficulties you're having starting maybe completely unrelated, and could be due to other causes (e.g., weak compression, fouled spark plugs, flooding, etc...). Switching to the colder (BUR10 heat range) plugs isn't going to help your starting situation as those plugs will tend to foul sooner on a street driven car - you should switch back to the factory recommended BUR7's (leading) & BUR9's (trailing) for a stock engine driven on the street.

Anyway, if you do need to replace the fuel pump, a great upgrade is to get an OEM Nippon Denso fuel pump for a mid-'90's (Mk IV) Toyota Supra turbo. You can find these at any parts retailer (Rockauto, etc.). It flows better than a Walbro 255, is quieter, and is OEM Toyota reliable. Costs about the same. Plus the fitment is a drop-in replacement for the FC fuel pump.

nyt

iTrader: (1)

also, might want to try the filter first, especially since they're cheap and easy to replace.

FC3S_Bat

The person i take the car to (town rotary mechanic/builder) took temperature readings from the headers while the car was running. Rear housing was up to +400°f front was +200°f he said according to his readings the rear was running lean...

FC3S_Bat

Also, when the car struggles to start, white/blue smoke comes out the back. Once the car starts, smoke will come out for 3-5 seconds. After that it doesnt smoke anymore, at all.

Is there anything i can mod to make it gain some power on the upper rpms?

Emissions were removed
Rb header
3" pipe, straight with muffler
Aluminum CAI
That's all.

diabolical1

iTrader: (3)

- change the fuel filter

- check the compression

- check the timing

- get rid of the colder plugs

- make sure your auxiliary ports are opening all the way, if at all

FC3S_Bat

Yes the aux ports are open. I removed the actuators sleves when motor was out.
Are the cold plugs good for Short term/track use only?
Thanks btw.

diabolical1

iTrader: (3)

will they work? yeah, probably. as long as they start the car and they're not fouling out while you're running they are okay to use.

however, i'm thinking the real question is are they a better choice than a hotter plug for your situation? i tend to think not, but i may not be the best qualified to say so with certainty. you will know for sure when you see how long they last and compare it to how long a hotter plug lasts.

for your leisure: https://www.ngk.com.au/technical_info/heat-range/