ZDriver96

Ok... The car starts easily on a cold start or if the car only sits for 5-10 minutes. But if the car sits for an 1-3 hours its hard to start.. Takes maybe five seconds of the starter turning before the car starts..
What could cause the car to not want to start as easily?

All ignition components are new except for the coil.

Stl94LT1

Do a fuel pressure leakdown test.

ZDriver96

Hooked a fuel pressure gauge up to it..

I primed the fuel pump (accessory on key position) and pressure shoots up to 40psi but does not hold. I thought the pressure was suppose to hold even if you turn the key to the off position.

I also pulled the vacuum line to the fuel pressure regulator when the car was running and no change occurred. I thought the PSI was suppose to increase because pulling that line simulated full throttle?

What do you guys think?

Also when the car is running it holds at 42ish psi... When I give it gas it jumps up. So when running it looks fine.

Car doesn't run bad but I thought that the PSI is suppose to hold in the fuel line. Thats why there is a bleed port there so you can relieve the pressure when taking the pressure gauge off

hey01

leaky injectors.


my car did the exact same thing to be except it went away after i stopped putting E10 in it. As long as i stay away from anything blended with ethonal its cool.

ZDriver96

https://www.camaroz28.com/forums/sho...=fuel+pressure

Found this good link from 2006 explaining the issue.

Quote from Injuneer

"There are four things that can cause the pressure to drop quickly.....

-leaks in the fuel lines.

-leaking diaphragam in the pressure regulator. You should have checked the vacuum pump before replacing the regulator, that would have told you if the regulator is the problem.

-leaking injectors. You can pull up the fuel rails, pressure the fuel system (do not try to start) and look for drips.

-weak check valve in the fuel pump. Hardest one to diagnose, but if you rule out the others, this is all that's left."



How do you check the vacuum pump though?

Stl94LT1

Pull the vacuum line off of the fuel pressure regulator. If it smells like gas, the regulator is bad.

ZDriver96

no fuel in the vacuum line. Gonna go pull the injector rail and see if any leaks show when I prime the fuel pump..

What possible harm can occur from having a leak in one of these areas?

seawolf06

Can't the motor hydro lock if too much fuel gets in the cylinder?

ZDriver96

just went out and pulled the injector rail... no injectors leak fuel when key is put to the on position..

So only a weak fuel pump check valve and leak in fuel lines left?

I had a shop put in a walbro 255lph about 6000 miles ago or year and 1/2. hmmm.


Not sure about it hydro locking? I thought that was only with water being introduced.

ZDriver96

I was thinking... there is no wetness in the vacuum line that connects to the fpr ... but... When i pull the vacuum line off while the car is running there is no change in pressure. I believe there is suppose to be a good increase in pressure (at least 5psi) when that vacuum line on the tip of the FPR is pulled off. So I'm thinking that could still be the problem??

sn8ke eatr

does it turn slow or normal speed

ZDriver96

Turns at a normal speed.

Hopefully when i figure out why my pressure isn't holding... that may fix my hard start issue...