WS6HUMMER

On my 00 3500 I'm having problems getting it to start especially when its parked on any kind of incline. I'll turn the key on let the "wait to start" light go out and it turns over like I ran it out of fuel. Usually after 3 attemps it starts. I have been going crazy trying to figure this one out, it never did this untill I had the fuel tank sending unit and lift pump changed. If its parked in my drive-way (which is pretty level) it starts no problem even after sitting all night. The only time it starts easy on an inclin is if I've just killed it within 30 minutes or less. Whats the deal with this, anyone ever have this kind of problem? What can I do ?
TIA
Hummer

CTD NUT

Sounds like the fuel system is draining down if it sits too long......I'm not sure what causes this......I have heard of some sender assemblies sucking air and causing hard starts and running problems when the fuel level drops below where the line has failed.

WS6HUMMER

Thanks alot anything helps, I'm completely in the dark on this one!

CTD NUT

No problem....I'll let you know if anything else comes to mind......others will chime in for sure with their .02.

BTW, any pics of that WS6? Sounds slick!

WS6HUMMER

Thanks alot man, I appreciate the reply and the help.
BTW I crawled up under there and found a leak @ the quick disconnect where the plastic line connects to the metal line that feeds the lift pump. I pulled and pushed on it to try to make sure the line was connected properly. If it leaks down again I'll pull that connection and replace the O-ring and post up how it turns out. And here's the pic of the car, please excuse my ugly mug, this is a profile pic I have on another forum.

CTD NUT

Sounds like you may have found the problem.......that could explain the leak down when shut down for awhile and the hard starting since it could suck air there. Good job.

Cool WS6! Looks like a wild ride! Pretty lady you have there too! I'll excuse your mug this time but hers can stay!

WS6HUMMER

LOL! Thanks we're gonna tie the knot sunday.

CTD NUT

Cool!! Congratulations...

WS6HUMMER

Thanks.

The line I thought was my problem turned out to be just a return line. I guess what ever's leaking is driping on that line and trickling down the return line. I even double checked all my injectors to make sure they were good and tight.....they were. Now I'm wondering what's giving me so much trouble, the line I thought was my problem T's in to the return line that comes off the back of the injector pump and another line that comes directly off the back of the head and has a banjo fitting on it. I'm assuming these are all return lines anyway, got any suggestions?

BTW when I cycle the key 3 times it reads "P Done" on the tripometer screen.

Clunk

Look at the connection on the fuel tank side of your lift pump. Somebody reported an air leak at that connection and just did away with that connector and used a small hose clamp to make the connection.

BigBlue

The quick connection on the tank is notorious for letting air in the lines. Replace it with a piece of hose pushed onto the fitting and put a hose clamp on it and be done with it. I've also heard of the return line leaking and causing the same problem. One of the members on here (I can't remember his name to save my life) had the exact same problem as yours and I think he finally solved it by replacing the return line. You could probably do a search and find out who it was and how he fixed it. If I were you though, I'd save your pennies and replace the whole fuel system. Run 3/8" fuel line from the tank to the injection pump and mount a holley blue on the frame and eliminate the stock fuel pump altogether.

That's a slick looking car. How you like that cam? I've been looking at it for my dad's C5. Congratulations on the wedding.

Huff nPuff

It replaces the old lift pump,with a fuel pump module in the tank.No more air leaks in the lines causing no starts or drivability problems.If it does leak it will show you where the leak is with a diesel leak, and probably wont shut you down.

BigBlue

The best pressure i've heard coming out of the new pumps is 8psi at idle and 1 at WOT. Not exactly a great thing on a VP44 equipped truck.

Huff nPuff

And 1lb of solid fuel flow is better than 20psi of frothy aerated fuel.Which is what happens when you line up High volume pumps and supply it with 1/4in of effective diameter supply line.The lines coming of the fuel module are very restrictive and are prone to leaking,under a strong vacuum thoughs leaks will froth the fuel.This wont happen if you pressurize thoughs same lines.

BigBlue

True. But I'd rather have 15 psi of fuel pressure than 8. My pump is mounted on the frame about midway between the tank and the engine and so far so good. Been that way for about 3 years now.