Bad fuel pump symptons...

[Boss 351]

Well I have a problem at WOT, and that is my engine is running out of fuel. Fuel filter is new and injectors are clean. I undid and checked my EFI harness before so that's in tip top shape as well. It's basically stuttering above 3500rpm but I don't hear any pinging.

One thing I noticed is that when I turn my electric fan on, my fuel pump makes a different sound. I still have the stock alternator on there so maybe my pump isn't getting enough voltage? I'm thinking about getting a better pump anyway, something like a 190 or a 155?

 

[superhuaman]

what kind of combo do you have?

you should have a 3g alternator (or any kind really if its bigger than stock) for your electric fan. that way you dont have to worry about voltage starvation of your fuel pump.

if you upgrade your fuel pump, just get a 255, theyre cheap on ebay, like $60

 

[Boss 351]

Currently it's stock but not for long. I have performer RPM intake, 65mm TB, 73mm MAF, 24lb injectors and aluminum heads coming in for my new engine which will be just a 306 for now. I was going with a stroker but changed my mind at the very last second...

 

[superhuaman]

oh ok...usually a stock pump will only be a problem when you upgrade other things, but if it's bad enough (like yours probably is) then it will cause that "rev-limiter" feeling. it would not hurt to change the pump. just drive until the tank is empty, and then drop it. i did mine in a couple hours.

EDIT
also, the fuel filter can cause this problem, but you said its fine.
is the problem present all the time, or just when the electric fan is on?
it wouldnt hurt to pull codes either...

 

[HISSIN50]

You've noted that pressure is less than adequate at WOT at 3500 RPM (or whereever your issue happens)?

The lack of pinging is a little strange.

I agree that with your plans, you'll need a pump anyhow - you can swap it early if desiring to do so.

Good luck.