Long crank time, fuel pump or injector?
I inherited my moms '97 4.6 thunderbird 8 years ago. She bought it back in 2000. As long as I can remember it always took excessive cranking before it starts.
I've been taking care of the car and did a full tune up last year, compression test, mustang wheel swap, vogtland lowering springs, trac-loc rear, etc. After all that I drove it about 800 miles and went back to driving something else. It's been driven maybe 3000 miles since 2008.
Recently I did some tests to see why it cranks so long.
After sitting overnight I connected a fuel pressure gauge, it read approx 5 psi.
One key cycle gave it 10 psi, another key cycle gave it 15 psi, another gave it 25 psi. It still cranked long before starting. It has 36 psi running, 45 psi with the fpr vac hose off. Turned the key off at 45 psi and it dropped to 35 and held for 15 minutes. I just assumed there was a problem and took the gauge off.
It runs fine though. I'm thinking either a check valve in the pump module is letting the fuel line drain back. Or one or more injectors are leaking.
What could the problem be?