R33 gtst not getting enough fuel

[vxsr33]

Hey guys

Basically took my car for tune at chequered tuning but for some reason my car is running lean above 10 psi boost and therefore not getting enough fuel, so the car was untunable.

I got a nearby shop to install a topfeed 1000cc injector kit before the tune.

My mods are power fc and z32, hypergear r34 highflow, blitz return flow cooler, full 3 inch exhaust, apexi pod, bosch 255 fuel pump and now the injectors.

This has got me stumped because my fuel pump is around 4 months old and ive changed my fuel filter within the last 7000km.

Could the workshop that installed the injectors done it wrong somehow?

Just looking for some possibilities on what could be causing this problem.

Thanks for any help people.

[wildeagle44]

Check fuel pressure

Has the pump been rewired or still stock relay setup?

Change filter again

e85 or 98?

[KiwiRS4T]

I can't find any reference to a Bosch 255 fuel pump. Sure its a genuine article? If it is in fact a Walbro they really need a direct power supply at full voltage. Can you get a fuel pressure test? Have a look in the tank to see if the pickup is compromised somehow. Put an airhose through your fuel lines.Did the tuner have any suggestions as to what to look for?

[vxsr33]

Thanks for the response guys.
No the pump hasnt been rewired and its on 98.

Sorry im not that familiar with fuel pumps it might not be that model but im pretty sure its an upgraded bosch one.

The tuner said it could be fuel pump, faulty fuel reg or fuel filter and they did mention it could be due to the wiring. I supplied a tomei fuel reg with the injectors in case the shop needed to install it.

Im picking the car up tomorrow and going to change oil and fuel filter. How can i do a fuel pressure test or do you need a shop to do it? Could rewiring the fuel pump fix the issue? Power im aiming for is 250rwkw

[GTSBoy]

Fuel pressure gauge install is the first thing that should have been done before the thing even stopped turning the rollers while it was still on the dyno.  The best time to check pressure is when you can sit there holding the dyno controls in one hand and the fuel pressure gauge in the other with bonnet open!

[vxsr33]

Fuel pressure gauge install is the first thing that should have been done before the thing even stopped turning the rollers while it was still on the dyno.  The best time to check pressure is when you can sit there holding the dyno controls in one hand and the fuel pressure gauge in the other with bonnet open!

Thats the thing with chequered tuning, they only strictly tune and expect your car to come in with everything running perfect. They wont diagnose problems for you or do any checks.

[KiwiRS4T]

250RWKW shouldn't require any massive fuel supply so there is a fault somewhere. If you are not comfortable with pulling the fuel pump out to check it you will need to find a shop to do the necessary checks on the fuel system and directly wire the pump. Stock FPR should be fine - they rarely fail but should be checked anyway.

[vxsr33]

Ok i will look into directly rewiring the pump myself.

I had to get an aftermarket tomei reg installed with the topfeed injector conversion kit. The tuner says that the fuel reg could be causing the issue and he also said it could be a knockoff non genuine one.

[HarrisRacing]

I don't see how an fpr could cause a drop in pressure on top unless it's plumbed incorrectly. Send us some pics of that first so we can make sure everything is plumbed correctly. Rewire is almost mandatory on these cars. Mine picked up a lot of flow with new wires. I'd be worried your pump isn't genuine

[vxsr33]

[vxsr33]

Heres some pics of how its setup. It took about 10 cranks to start the car this morning which isnt normal, it usually starts immediately, even cold starts

[Dale FZ1]

Be wary about linking the cold start and full load fuel delivery issues.  Probably totally unrelated.

Cold start will be something in the tune.

Fuel delivery problems probably the pump wiring and/or a kinked/restricted fuel line as per previous posts.  At 250rwkW you aren't really asking too much in terms of flow capacity.

Sounds like you need a tuner who will/can work with you to diagnose and solve problems.

[Guilt-Toy]

the walbro 255 needs to be run with a relay,  also mistakes made during installation could also cause this.

 

[HarrisRacing]

I'm leaning toward something kinked with fuel lines in tank. I replaced the factory hoses the first time i did my pump and they didn't hold shape and kinked. Went back with factory and it worked fine after. Does your fuel pressure hold when you shut the car off?

[vxsr33]

Thanks everyone for the input

Right now im thinking i might as well get a new fuel pump just in case it isnt genuine, check all the hoses, directly wire the fuel pump and change the fuel pressure regulator, it might be a fake tomei one and i dont want to risk it.

Can anyone recommend a good fuel pump and fuel pressure regulator for my needs?

This stuff is new to me but im willing to give it a go myself.

[KiwiRS4T]

Stock FPR - you may need an adapter to fit it to your aftermarket fuel rail. Walbro should do it.

[tridentt150v]

I wouldn't waste any $$$ until I had the fuel pressure checked.  Its a simple 5 minute job and any mechanic can do it.  You need to diagnose the weak link..........no use spending $1,000 for a $5 fault.

[89CAL]

^ ^ This x 1000 ^ ^

[vxsr33]

Its not that i want to waste money, its just that i would rather the peace of mind and reliability of having a new fuel pump and directly wiring it. I will bring it to a mechanic to get it pressure tested.

Can anyone point me in the right direction with how to put the stock fpr back on. Because as i said i think my tomei one might be a fake item (didnt know prior to it being fitted). Where can i get an adaptor for it?

[tridentt150v]

Sorry, but are you listening????  Don't do anything till you get your pressure tested.  You need to find the fault before introducing more random parts and issues.