i have had a new cam (xe224/230 112) for a couple months now and it has been tuned by pcmforless. however i feel like the power is not really there. i know my fuel pump is pretty weak because it has a hard time starting, especially when low on gas and i have a new fuel filter, opti, plugs, wires etc.. Anyways i was just wondering if a fuel pump can be responsible for a loss in power even though it runs fine?

 

It's possible but the best thing to do is check with a fuel pressure gauge, it screws in behind your intake there is a fuel fitting, run it through your hood, gently close it, angle it towards your windshield where you can see it and test drive, should be around 43psi I think for stock, it may drop under load to about 37-41 give or take a little but no less. If it's an aftermarket sometimes if the hose on the fuel pump (where it bends with the fuel tank level) is not set correctly it can actually crimp the fuel supply. Others may have more expert advice, but hope this helps a little.

 

anybody else, or is this the best route to follow??

 

How many miles on your stock pump?
I hooked up a guage to mine and it seemed to be within specs, I did not tape it to the windshield and do WOT testing though.
My car seemed down on power somewhat so I put in a Walbro that I had sitting here just collecting dust cause I was too lazy to put it in.
Car pulls much better up top now.
I think my old 135k mile pump was getting weak. It starts much better now as well.
Need to get to the track and see if my numbers improve.

 

I'm not sure if just checking pressure is the way to test a fuel pump.
You also need to check volume. There should be a spec somewhere that tells you how much fuel it should pump in a certain time period.
You can have pressure and not have volume.

 

Yes, the pump can be the reason for the loss. If the pump can't keep pressure up top, you will be losing power. Even more dangerous is that you will be running extremely lean at those RPM's.

If you do a pressure check, monitor the guage all the way up the rev range. It should hold steady. If it drops at higher RPM, it's an indicator of a failing pump.

You can also run a scan and watch your injector constants as the RPM's climb. Climbing pulse-widths and a corresponding low O2 millivolt reading points to a pump that can't keep up. Running too lean can damage your engine.

 

NOT at WOT! If you don't have the volume at WOT the pressure will show a corresponding drop as well...

 

Not according to Holley's tech line. Maybe fuel pressure with fuel injection and carbs is different though.
The example that was given by them was to go play with your kitchen sink. If you turn it on about 1/3 way you have volume and pressure. If you crank it open more you are going to have a much greater volume at nearly the same pressure. Kind of a crude example, but it works.
The car in question had a steady a/f ratio on a wideband but power just stopped at about 5000rpm and stayed consistent. The stock 3/8" fuel line was killing fuel volume even though fuel pressure stayed consistent. Holley's reply was it's time for a bigger pump and fuel line because of the lack of volume.
But like I said, maybe with the higher pressure a fuel injected car operates at there would be more of a drop in pressure if volume is lost. But I'm not sure...

 

Your example would be true in a case where the lines aren't matched to the power output. I don't think that's the case here. The stock fuel lines are more than enough for the horsepower we are talking about. He isn't anywhere close to maxing them out. In this case, the loss in pressure at higher RPM's would be a good indicator of a pump that is weak or failing.

 

Pressure is a good indicator 99% of the time. That is what you need to check with a gauge. Your engine definitely needs proper pressure for the injectors to deliver the fuel as they should.