Trouble Starting (Fuel Pump Upgrade/Replacement)

[joseph0205]

Ok, so, I've been having problems with starting my 98 R33 Gts-t recently. It can vary from turning over and never firing to starting but running very poorly and stalling to working fine seemingly at random. On more than one occasion, by playing with the fuel pump wiring, fuse or plug the car will start and run perfectly, i do not know if this is the actual problem because it seems so intermittent however, i do know that the car will run roughly/stall without the fuel pump plugged in (I swear I didn't forget to connect it, i was "testing"). If anyone has had a problem similar to this and fixed it that would be great to hear but being vague and intermittent I don't hold much hope.

The real meat of this post is, if i were to replace the pump is there a nice drop in replacement that doesn't cost and arm and a leg while not being from the Chinese lucky dip bag on ebay? my other thought was to upgrade to a Walbro 255 (GSS340) or a Bosch 040 because eventually my plan is to buy something reliable and diesel (and high off the ground so ramps aren't necessary for everything ) and throw some money into this car so i figured i may as well plan for power as i'm most likely to get a new car within a year. But i have read mixed things about both the bosch and walbro from a general trawl through the forums, is there a clear winner? Also if i do end up going this option, do I have to upgrade the wiring to the pump and what is the best way to go about this, my thoughts are to use the current power wires to trigger a separate fused relay.

 

Anyway, thanks in advanced for any help

Joe

Edited September 18, 2018 by joseph0205

[iruvyouskyrine]

Very difficult to diagnose over the internet, but a new fuel pump can only be a benefit. Clear winner is Walbro 255 which can be had for around ~$130 just make sure you buy from a reputable source online (EFI Hardware etc)

Also remove and clean AFM and check the wiring to the AFM isn't burn or missing a ground.

[joseph0205]

I have found that the pump runs perfectly when just wired straight to the battery and the car will start and run beautifully so its down to either the wiring or the fuel control module which is conveniently hidden under the rear seat, wish me luck?

[iruvyouskyrine]

The good news is you can put the FPCM straight in the bin. Use the ecu fuel pump trigger (usually a pull to ground) to trigger a relay (any 30A relay should be fine) and then run a new appropriately sized wire straight from the battery, through the relay and to the fuel pump. Won't have any more issues.

[joseph0205]

5 minutes ago, iruvyouskyrine said:

The good news is you can put the FPCM straight in the bin. Use the ecu fuel pump trigger (usually a pull to ground) to trigger a relay (any 30A relay should be fine) and then run a new appropriately sized wire straight from the battery, through the relay and to the fuel pump. Won't have any more issues.

That IS good news ? what is the use of the FPCM does it control the pump with PWM or is it just one of the Japanese complexity for the hell of it type deals (IE the idle air system).

Do you happen to know the colour of the ECU trigger wire?

Also there is already a large relay attached to what look like the main wires of the fuel pump attached to the side of the boot fuse box but it looks very OEM so I may have the wrong thing (I just matched the wire colours and that's never reliable)

 

Anyway, thanks for the terrific news 

Joe

[iruvyouskyrine]

I know in R32 it's the white wire with purple trace however i have never done it with an R33 so can't comment on it directly. However with a multimeter and some googling i think you should be able to figure it out pretty easily.

Also the FPCM is just a two stage device, under condition X the fuel pump receives 10V and under Y it gets 12V. Better to run it at full voltage all the time. 

[tridentt150v]

fuel pump wire is black with a purple trace at the ECU...from memory. 

And just before you go tearing wires out and throwing them over your shoulder, try running the pump with a dedicated earth wire first.

Plenty of time to go wire mad afterwards.

 

[joseph0205]

2 hours ago, tridentt150v said:

fuel pump wire is black with a purple trace at the ECU...from memory. 

And just before you go tearing wires out and throwing them over your shoulder, try running the pump with a dedicated earth wire first.

Plenty of time to go wire mad afterwards.

 

I have tried hooking a solid connection straight to the grey wire connection of the FPCU to ground and nothing has changed, so it is either the wire itself or something else i don't know.

 

I have drawn a little mud map of what i believe is the wiring diagram but i can't really make sense of it myself. So the black-pink/purple wire into the relay in the boot is the trigger from the ecu which must mean the blue-white is either a ground or 12v supply from somewhere (depending if the ECU pulls the black-pink/purple to ground or if it supplies it 12v) however, it didn't show any voltage or continuity with ground. (from memory i believe the black-pink/purple showed like 4M ohm to ground while the car is switched off so i assume that the ECU drops it to ground). 

 

Now the light blue wire branches of to 3 places, the input of the FPCU, the front of the car somewhere and the main line into the  positive side of the fuel pump. The grey wire is what i believe to be the switch for the fuel pump by allowing it to connect to ground when the FPCU is happy (maybe i should buy it flowers or something, it doesn't seem to like me much) and gets triggered by an orange wire that i believe i have read is triggered by the ECU only when it senses the engine is turning (using either the force or the CAS, neither would surprise me at this point). this grey wire also runs to a random connector which is apparently a ballast hidden in the boot somewhere. Black is just the ground for the FPCU.

 

So my questions are:

1. Which of the black-pink or blue-white should be showing voltage and/or ground?

2. if i were to do away with the FPCU should i just have the relay trigger from the orange trigger line or go back further?

3. WTH does a ballast do?

4. How big was the average Japanese factory worker in 1998?

EDIT: I'm also planning on possibly future-proofing this whole system if i ever go for bigger power, will the light blue and grey wires handle, say a walbro 460 (probably never need it i just don't want to strip the car and wiring down like this again, just swap to a bigger fuse and go for it) or should i replace them with something beefier, i figure to handle up to 30amps. Will the ballast (whatever the hell that does) handle it?

 

 

Thanks for your help so far,

Joe

Edited September 19, 2018 by joseph0205
added more questions :P

[GeeDog]

Does this help?

[joseph0205]

1 hour ago, GeeDog said:

Does this help?

 

You don't happen to have the full photo or atleast know where pin 2 on the fuel pump relay goes to?

 

Cheers,

Joe

[GeeDog]

I can't remember where I got those from, but used them to rewire the fuel pump in my R33 GTST track car. I think pin 2 is 12V through the ignition switch - so live when the key is on or start - and the ECU switches pin 1 to earth to run the pump. A couple of minutes with a test light would confirm this.

[KiwiRS4T]

13 hours ago, joseph0205 said:

I have tried hooking a solid connection straight to the grey wire connection of the FPCU to ground and nothing has changed, so it is either the wire itself or something else i don't know.

 

I have drawn a little mud map of what i believe is the wiring diagram but i can't really make sense of it myself. So the black-pink/purple wire into the relay in the boot is the trigger from the ecu which must mean the blue-white is either a ground or 12v supply from somewhere (depending if the ECU pulls the black-pink/purple to ground or if it supplies it 12v) however, it didn't show any voltage or continuity with ground. (from memory i believe the black-pink/purple showed like 4M ohm to ground while the car is switched off so i assume that the ECU drops it to ground). 

 

Now the light blue wire branches of to 3 places, the input of the FPCU, the front of the car somewhere and the main line into the  positive side of the fuel pump. The grey wire is what i believe to be the switch for the fuel pump by allowing it to connect to ground when the FPCU is happy (maybe i should buy it flowers or something, it doesn't seem to like me much) and gets triggered by an orange wire that i believe i have read is triggered by the ECU only when it senses the engine is turning (using either the force or the CAS, neither would surprise me at this point). this grey wire also runs to a random connector which is apparently a ballast hidden in the boot somewhere. Black is just the ground for the FPCU.

 

So my questions are:

1. Which of the black-pink or blue-white should be showing voltage and/or ground?

2. if i were to do away with the FPCU should i just have the relay trigger from the orange trigger line or go back further?

3. WTH does a ballast do?

4. How big was the average Japanese factory worker in 1998?

EDIT: I'm also planning on possibly future-proofing this whole system if i ever go for bigger power, will the light blue and grey wires handle, say a walbro 460 (probably never need it i just don't want to strip the car and wiring down like this again, just swap to a bigger fuse and go for it) or should i replace them with something beefier, i figure to handle up to 30amps. Will the ballast (whatever the hell that does) handle it?

 

 

Thanks for your help so far,

Joe

If you want to future proof it you will need to run a bigger supply wire and fuse...easy if your battery is in the boot otherwise you need to run a wire the length of the car. The stock trigger wires should be fine unless they have been damaged.

[joseph0205]

8 minutes ago, KiwiRS4T said:

If you want to future proof it you will need to run a bigger supply wire and fuse...easy if your battery is in the boot otherwise you need to run a wire the length of the car. The stock trigger wires should be fine unless they have been damaged.

Yeah, it's all in the boot that's why I was thinking over doing it while I have it all apart. And the trigger wires LOOK fine but I was asking which trigger wire I should be using, the black-pink from the ECU that powers the whole FPCU system or if I should leave it be and just replace the FPCU with a relay and use the orange trigger wire?

[joseph0205]

So by looping the blue-white wire on the relay found in the boot to 12v everything starts and runs beautifully and by what i can find about a standard R33 GTST that's just how it is done (the first picture). However, unless this blue-white wire talks the long way and runs from the power source in the boot, through the cabin and back again to get 2 inches away from where it started it must be doing something else. 

I also found a RB26DETT wiring diagram that does have the blue-white wire running to the front and into the O2 sensors on both the turbos. SO is there something different with the series 2 R33 or do i have a RB26DETT Loom in my car with a 25DET engine. I need to use the car so I am just going to wire it for now but any insight would be great.

 

Cheers,

Joe