As it says, my Z has trouble starting when its not been heated up. After i run it for about 10-15 mins, it can turn right back on no problem within the next half hour. My first thought was the fuel pump. But i got a pressure guage and heres what i got...
With the ignition on (pump priming) 44psi
Ignition on (car still off, and pump done priming) 36psi
Car running is a steady 35psi.
I also noticed that if i primed the car and then turn off the ignition, i loose about 1psi every two mins.

So the pump is ok with priming the car, so i dont think its that, but im pretty sure that the fuel pressure is supposed to hold at 44psi instead of drop as soon as the pump is done priming. so i checked the vaccumn to the regulator, it its a good steady 20 In of mercury. Any ideas on what the problem could possibly be? Thanks

 

also just to clarify some more, the battery is new and all, and it cranks easily. IT just takes about 15 seconds before it can start. In the 15 seconds, there is several pops and stuff like its trying to hit, but doesnt.

 

More than likely it is the fuel pump but not in the way you think. There is a check valve in the pump and it appears to be leaking and allowing the fuel to drain back away from the fuel rail. You saw the problem when you said the pressure drops about 1psi every 2 minutes.

To confirm this is the cause of the hard starting, the next time you start it after sitting for a long while, cycle power on for 3 seconds but don't crank the engine. Then off. Do this 6 or 7 times and after the 7th time, crank it like usual. If it now starts very quickly, you know it's from the fuel draining away from the fuel rails.

There are other ways to fix this problem other than replacing the fuel pump.

 

Well, usually the priming method works ok with my car to start it. Now what should i do about this check valve business? this pump isnt very old (like 2 years old), but things go wrong everyday, so there no doubt in my mind that its the check valve. Whats the easy way of doing it instead of replacing the pump?

 

Could also be the fuel pressure regulator. Check the vacuum hose coming from the FPR (on back of intake manifold) that goes into the passenger side of the intake. If it smells like gas, or has liquid in it that could be the problem.

 

If you check the fuel pressure and everything checks out, try your plugs and wires. Mine would crank forever and had a helluva time starting cold, but I changed my plugs and it starts first try everytime

 

If the pressure regulator where causing your problem, the long amount of cranking to start the vehicle would be from flooding. So cycling power before cranking would only exasorbate the problem. Also, the longer the car sat, the easier it would be to start since the fuel would evaporate off. Also it would richen up the A/F ratio and really screw with the fuel mileage when you ran around town.

The other method to fix the problem would be to install a check valve inline but it's not easier than replacing the fuel pump. It just gives you another challenge that happens to a better way to deal with the problem. But notice I said challenging. I recommend the Aeromotive check valve and it can be adapted from the hard lines to the 6AN size quite easily. For us that have a different fuel system that is.

There appears to be more pumps that fail due to bad check valves than any other problem. Wouldn't it be nice to not have to replace the pump every time this happens. And once the check valve is installed, it can be replaced even more easily than replacing the fuel filter. I also recommend the installation of a petcock to allow changing fuel system components without draining the entire tank. Seems I can never anticipate when the fuel system needs attention and always have a full tank.

 

k new update, i just looked at my spark plug, and according to autozones website, they are the spark plugs for the ls1 camaros and not the lt1. u think that could be the problem?

 

Not unless the reach of the 2 plugs is different.