03 hard to start

[Sireal]

My 3.7 has been hard to start for quite some time now, usually takes 2-3 attempts to fire up but runs fine once it does. Doesn't matter if cold or hot. I've replaced the fuel pump, fuel filter, throttle position sensor, injectors and spark plugs. Starter cranks like a madman. No codes. It always starts eventually but still annoying as hell. Any ideas?

 

[Sireal]

Ok so I finally got my fuel pressure test set and found out my fuel pump check valve must not be holding pressure. I replaced the fuel pump initially but can only assume it's also defective. I get 53 psi when ignition on then it drops almost instantly to 0 with key off. When I get it started it reads 53 psi and holds until I shut down. I am also assuming this is causing a vapor lock situation when the engine is hot which would explain it being harder to start when hot. I'm tempted to install an inline check valve on the fuel line to verify my suspicions. I was going to say screw it and get a mopar fuel pump assembly (replacement was Delphi) but it seems they aren't available anymore? Anyone know if there is another path for fuel to bleed off to the tank (I'm under the impression it's a returnless system)?

 

[Sireal]

Ok so I finally got my fuel pressure test set and found out my fuel pump check valve must not be holding pressure. I replaced the fuel pump initially but can only assume it's also defective. I get 53 psi when ignition on then it drops almost instantly to 0 with key off. When I get it started it reads 53 psi and holds until I shut down. I am also assuming this is causing a vapor lock situation when the engine is hot which would explain it being harder to start when hot. I'm tempted to install an inline check valve on the fuel line to verify my suspicions. I was going to say screw it and get a mopar fuel pump assembly (replacement was Delphi) but it seems they aren't available anymore? Anyone know if there is another path for fuel to bleed off to the tank (I'm under the impression it's a returnless system)?

In case anyone cares, my replacement fuel pump did indeed have a defective check valve out of the box. The replacement for the replacement works perfectly. Thankfully the Delphi fuel pump from Rock Auto had a limited lifetime warranty.