Finally had the car tuned and the fuel pump was at 115% around 330whp. A few months ago I did a brand new walbro 255. What could be causing it to max so soon? Probably going to just order another one in the near future but just curious to what caused this in the first place...

 

it was also in the car for two months before being tuned

 

You might be confusing your fuel pump with IDC (injector duty cycle.) You need larger injectors

 

He said specifically that it was the fuel pump though. Spec ops tuner too so he does know his ****... I did ask about the injectors and he said it was definitely the fuel pump.

 

I got to 374whp on the stock pump so something is defineatly wrong, a walbro 255 should be good for around 500whp.
Have you tried measuring voltage going to the pump?

 

No I have not even gone into it since we changed it.

 

If this is Cody, then yes it seems to be the fuel pump... an evo VIII with mild bolt ons a Walbro 255 and stock injectors usually max out at around 350 dynojet... this car could barely make it to 300... it was at like 106% IDC at 22 psi after turning it down after the injectors were static at 25 psi... You need to check the wiring and voltage to the fuel pump and make sure you aren't dropping voltage during a pull and that it is stepping up the voltage when you transition into boost... The car did have an AEM in it with the previous owner, so I don't know if the wiring was messed with or not...

 

You need to figure out what is wrong with your car not just but a new pump.

 

I did not even think about Brandon's setup being wired different... That makes sense to me. I could ask Brandon if it was wired any different to stArt with also. Thank ya Freddy!

 

Something is wrong with the car too possibly

 

Spoke with Cody this morning and informed him the car was rewired when I had it. I'd presume Mike returned it to the stock setup when he took the Buschur double pumper out though.

Definitely not impossible for a bad Walbro either, I've been through a couple in my day.

 

I'm going to volt test it on Monday at Mikes when I get off work. I have to go over there anyway. Then I'll just go from there.

 

One thing is clear, a Walbro 255 lph pump cannot be expected to deliver full capacity with the factory wiring. Drifto verified this long ago, when we measured about 13.5V at the pump while under load. We found that upgrading power and ground with dedicated wiring brings 14.3V to the pump. Check the voltage vs. flowrate graphs, and one will find that while 0.8V doesn't seem like much on paper, it makes a substantial difference.

FYI

 

Good info. I'll keep that in mind when testing the voltage next week. Thank you sir.