Okay this fuel problem my car is having is driving me insane. I just got my car rebuilt , street ported, and put headers , removed all cats and switched from backpressure 5th and 6th ports to an air pump so I could open up my exhaust. << that is just background info.

So it started with my fuel tank leaking drops of fuel. After I already had to rebuild my motor cause it started leaking coolant and oil. I found a rust free tank on ebay bought it and had it shipped to my house. It was very clean and rust free. I had the mechanic put it on. Problem solved..

Now there is no leak but whenever I stomp on the gas the car does fine until its powerband and starts to buck and surge. I figured a fuel filter was clogged so I took it back to my mechanic and he found no filter clogging.

The strange part is , it only has this problem when it has a 1/4 tank or less. If I put a full tank in, the car go to redline in every gear with NO problems. Is the stock pump no longer adequate since my motor is modified? I don't see how the fuel level affects the pumps ability to keep up...

I thought maybe it would be a fuel injector clogged because sometimes I smell richness of gas from my engine bay and my fiance freaks out and rolls down the window...

but the full tank or 1/4 tank makes me think its the pump?

If I do need a new pump what is a good stock replacement pump?

 

Any trouble codes?
Have you verified the ECU is operating in closed loop mode?
Have you tested the fuel pressure? Have you monitored the fuel pressure while it is doing the surging/bucking?

 

I have not hooked it up to anything
I do not know how to verify that the ECU is in closed loop mode.
I dont have a way to monitor fuel pressure.
I think its my fuel pump.. cause whether or not it bucks soley depends on
1 fuel level and load level. Maybe the pick up tube is too high?

 

did you check the condition of the tank baffeling before you put it in?

 

You can get a decent fuel pressure test kit for about $30... put a long enough hose on it and you can run it up under the rear of the hood and tape the guage to a windshield wiper and then go driving in the condition (1/4 tank?) where you think the problem is. If it is fuel pressure, either via a failing pump or a misplaced fuel pickup, you will see the variations in the pressure on the guage. If not, your theory is incorrect, it is another problem, and you will have saved yourself a lot of time and money by not buying parts you do not need.

 

I take that back. Here is what looks to be a perfectly servicable fuel pressure test set for $16.99

http://www.harborfreight.com/cpi/cta...emnumber=92699

 

well it is getting worse now. The car now has the same symptoms at a half tank.. I guess it is a failing fuel pump. I guess they just gradually fade? I have never had fuel pump failure before so that is why I am rather unfamiliar with the problems. It just cant keep up once I get to 3500-4500 rpms and no matter what gear im in if I stomp on it , it will buck and hesitate.. gosh
384$ and counting to fix this cars re occurring fuel problems..

 

http://cgi.ebay.com/ebaymotors/WALBR...=p4506.c0.m245

So I am trying to save some money but get a good pump. The replacement pump at advanced auto is a bosch pump but it runs 153 dollars. I have seen a lot of people use the walbro 255. Will the pump in the link above be just as good as the bosch. Im just trying to avoid hearing my mechanic say "it doesnt fit" and have to buy ANOTHER one....