I own a 1988 GTA with a 305 and a 5-speed. About a year and a half ago, I started having a problem with my fuel pressure. It would vary between about 17-25psi, enough to keep the car running but certainly not running well. I thought (perhaps erroneously) that if the regulator was bad it would have a more consistent reading, but since there was a good degree of variability I replaced the pump. I can't recall the brand of pump that went in or came out, but i do recall they did look a little different. The car wouldn't run at all after this.
Fast forward until this weekend, having some free time I dove into this project again. After fixing a sloppy install of the new pump, I'm now able to get the car to run again, albeit only briefly. I now have 10psi of fuel pressure, and after extended cranking she may run anywhere from 2-30 seconds. I clamped off the return hose to the tank thinking maybe the regulator was bad but it made no difference, in fact the return line isn't getting any fuel through it at all, it seems. I'm assuming that's because at only 10psi there isn't exactly any extra fuel going back to the tank. Also, as soon as the pump shuts off it instantly bleeds off all pressure, in, like, 1 second.
So, I'm wondering, how common is it to be sold a new pump that's bad? Or somehow damage the pump wrestling it in the car? Is it possible I installed a TBI pump in my TPI car? Or should I start looking towards leaky injectors or a new regulator or some other component? Thanks in advance for any help.
Cory

 

Its more common that you'd think possible. I went through 3 pumps in 1 month, yes 4 weeks! Cost me 160 bux in towing that month. ;( Buy another pump.

 

Thanks for the response. I was leaning towards the fuel pump being bad but it seemed counter-intuitive that a new part isn't going to work properly. Is there a certain brand I should avoid or a certain brand I should try to get my hands on?
Cory

 

I put in a new pump and still have the same problem. I blew air through the fuel lines and took out the fuel filter and replaced it with a rubber hose just to eliminate the possibility of an obstruction causing this problem but it didnt make a difference. Any ideas?

 

check the fuel pressure regulator

 

clamp off the return line with a vise grip and see if the pressure goes to 65psi. if it does your pump is fine and its the regulator. if it makes no difference check the cold start valve. it could be stuck open. If its not that then remove the IN line at the rail and check pressure there, again it should be 65. if it is it is not your pump. It is a leaky injector. Don't just keep throwing parts at it. If the tests point to a pump make sure all the hoses are properly attached to the pump in the tank.

 

IROCUROC- Should the IN LINE pressure be more then what is at the fuel rail? I thought that the pressure at the fuel rail is 45-47psi!??? And what about the fuel filter??? during the pump swap, dirt and crap could have fallen down into the tank and plug something down in there!(just a thought).

 

The line pressure BEFORE the regulator will indeed (or, at least, should...) be higher than the rail pressure. Pinch off the return line, See what happens.

 

I did try pinching off the return line but had the same result. I also bypassed the fuel filter with a rubber hose but that didn't make a difference, either. I never checked the pressure at any place in the system other than the schrader valve, but I fixed the problem before I needed to. I filled an ice cream bucket up with fuel, stuck the pump in, and turned it on. My roommate's Yamaha Blaster was soaked with about a 15-foot fuel geyser that was squirting out the pressure line about midway between the pump and the plate that mounts the assembly to the top of the fuel tank. I also had a hole directly opposite on the return line. Did their use to be some sort of bracket there that is probably in the bottom of my tank now? The only thing I can think of is, that their was a bracket welded to those 2 lines that I must have broken off pulling the pump out the first time. When the bracket broke loose it left 2 little holes inside the tank on the pressurized line and the return line. Does that sound plausible?

 

i guess, go pull the tank, otherwise we are guessing.

 

What are you using to couple the new pump to the fuel line? Sounds to me like you have a bad pulsator valve or a leaky coupler hose.

 

 

I'm with John 89, when I had to install my fuel pump, I had to use a rubber coupler IN the TANK to get the fuel pump to connect to the metal hose that went to the front of the car. You bolt on the fuel pump the the sending unit assembly then bolt the coupler to the hose that leads to outside the tank. If that hose is faulty and not clamped properly, the fuel pump is just going to flow fuel all around the fuel tank...