Ok same problem I posted a while ago. 85 iroc, TPI, auto, crane regulater. Fuel pump started to get loud and then the car lost a LOT of power when I gave it gas, so I figured the pump was going bad. I replaced the fuel pump and in-tank filter, but not the ext. filter because it looked really new. Anyways, long story short, new pump started sounding like the old one (getting real loud towards the end of 15 minute trips around town) and the car had the SAME stupid problem, started to crap out after the car was on for a period of time, give it gas and its like it has no fuel, so I replaced the brand new intake pump AGAIN, this time with a new ext. filter, new strainer, ect................well guess what. SAME PROBLEM IS THERE!!! AWWWWWWWWWW!!! Car runs beautiful for exactly 1 minute, then starts to run like crap and the fuel pump gets real loud. I have NO idea whats going on. When I popped the hood one time when the car was starting to crap out and stall, the pressure gauge was steadily going DOWN. 40......30.............20..........stall. I don't get why the pump won't hold pressure and why its getting loud. This is the second new pump, new filter, and a brand new Crane regulater set to 47 psi. What gives??? anybody??? pleeease!!

 

Did you ever pull off the new "external" filter and checked for it being clogged?

 

what happens if you crack the fuel filler neck cap open when it starts dropping psi? another thing maybe power to the pump like the oil psi switch?

 

yep and yep. The first "new" ext. filter was somewhat clogged, had some rust residue in it, but the new "new" ext. filter I took out twice today and yesterday to check it, its perfectly clean, blows through really easy. And yeah I tried driving with the gas cap off too, makes no difference.

 

How do your fuel lines look? I have to change my fuel pressure line that goes from the fuel filter to the throttle body tomorrow because it is badly corroded and partially clogged.

The Trickster!!!!!!!!!!!!!!!

 

Did you clean your tank out? ANY dirt at all in the tank will screw up the fuel pump. The strainer only catches the biggest peices. Everything you see in the external filter went through the pump once. The pump is basically 2 plastic gears meshing and spinning, so if a chunk gets caught between them, it can either jam them, or wear them out/cut a groove in them. Sometimes if a tanks extremely dirty bout the best you can do is replace the whole thing.

 

Have you inspected the fuel supply line from front to back?
Maybe a stone hit the line somewhere and dented it.
The rubber portions of fuel line may be suspect also.
I've seen where the inner layer seperates and lays over blocking most of the fuel flow.

With a cold, non-running eng;
Try disconnecting the fuel return line just above the steering box where it goes from rubber to metal.
Place the disconnected rubber line in a container and power the pump so it runs continously (well for 30 secs or so). Not sure what the flow rate is supposed to be, but you should see a pretty good flow.
If the flow is weak, try the same thing with the fuel supply line.
If it's still weak, start working your way back towards the gas tank.

With the pump groaning like that, you have a restriction somewhere or the pump has become damaged.

 

Thats a good idea, I think I will try that at work tommorow. If that doesn't fix it, I'm clueless and I will definitely sell the car. A shame too, because even though I'm used to driving my firebird, this little 305TPI hauls *** when it runs right.
Chris

 

possible pin hole in your fuel line?fuel pump relay getting weak,its on your firewall beside the brake booster,,had the same problem on a 87 formula,,relay and new fuel line fixed it

 

Voltage to the pump (measured at that little block behind the rear passenger seat) was a solid 14 volts while the car was running so I don't think thats the problem. I'm stumped, I'm literarly going to put the car in the paper tommorow