I installed a Walbro fuel pump about 2 years ago now on a '97 Lt-1 and have had starting problems ever since. It takes about 10 seconds of turning over before it will start if I don't prime the pump. If I prime it 2 or 3 times, it will start relatively normal. I do have a fuel pressure guage on the fuel rail it it shows solid pressure when I prime the pump but it immediatly drops off when the pump is done priming. It seems as if the pressure is bleeding off somewhere. Any ideas before I go ahead and drop the tank to pull the pump out again?

 

i know it's just a check ball issue, not sure where it is though, i'm thinking its not in the pump but the can? the check ball should stop fuel from draining back and hold steady pressure with the key off. that's why it's hard to start because your loosing all pressure.

 

well its def. hard to start due to the press. bleeding off, and it can only happen for one reason. a leak. now, there are 3 poss. locations for this leak that would not show as an external leak. #1 and most common is the pump itself. there is a check ball inside the fuel pump and it should stop the fuel from returning to the tank through the pump itself. since this started at the same time as your pump install, its prolly the pump. but the other two poss.s are #2 the regulator. it could be ruptured and bleeding the press. off into the intake mannifold through the vac. pipe. disconnect the hose when you key it on to press. the system. you'll see it come out the line nipple on the regulator. and the last possibility is an injector thats sticking on. GM has special lines that would plug in between the fuel rail and the feed/return lines that have shutoff valves in them. that makes it really easy to determine exactly where the fuel is goin. but, most cars have some rubber line in them somewhere you can pinch off with vise grips to do the same thing. Im not sure if the LT1 has any rubber in the fuel line anywhere though. DO not pich off the plastic lines. lol. obviously theyd break. you could rule out the fuel inj.s though by lifting the fuel rail out of the intake, keying up the ignition, and makin sure NOTHING comes out of the inj.s. dont crank it, cuase then fuel WILL spray out.

 

it could be a pinhole in the hose from the pump to the sender top(inside the tank) as well

 

I doubt it's the fuel pressure regulator because I rescently put an aftermarket one on and it still does the same thing. I have also tried a different set of injecters and they didn't make a difference either. There is no external gas leak, I know that for sure. It has to draining back into the tank, possibly through the pump.

 

excellent idea. I even had one blow the crappy little supplied hose right apart. that sucked cause ofcourse the tank had to come back out to replace the hose. I learned not to use that cheap crappy rubber line that comes with the kits. that one was a granetelli (repackeged walbro).

 

I'm 99% sure I found the problem. After ripping out the rear-end and half the exhaust and the tank, I pulled the fuel pump out, turned on the ignition and found the gas was leaking like crazy where the crappy clearish-yellow plastic line clamps on the the sending unit hard line. It was clamped on there with a hose clamp provided with the kit. I tried tightening it but to no avail. I'm simply going to replace it with some rubber fuel line and several hose-clamps. And to think I was running nitrous like this...yikes!

 

FWIW, make sure you get the proper line for the job, or that will just happen again in the future.

 

dont use that supplied line OR the factory accordian line. just take it off and get some HIPRESSURE fuel line. and another tip, when putting on the clamps, do not overtighten them cause you can cause the clamp to cut into the hose, making it weak and possibly making the same problem come back. but, do make sure it is tight enough to hold. you might want to do the same test after replaceing the hose before installing it into the tank the rest of the way and reassembling the exh.