I have a 95 dodge ram cargo van with a V8 5.2 with 103k miles. When my engine sits overnight, it take several tries to get it to start. I decided to perform a fuel pressure test today. As I suspected, I was getting no fuel pressure when the key was turn to ignition ON position. Only when the engine is running, I was getting 60 psi. Immediately after the engine is shut off, the fuel pressure is dropped to zero within 2 seconds.

Through researching, I think the problem is the entire fuel pump unit. Has anyone have a similar issue where fuel pressure drops this fast? What are the chances that its the fuel injectors causing this? I want rule things out before replacing parts. Any advice is appreciated. Thank you.

 

I have a 95 dodge ram with a V8 5.2 with 103k miles. When my engine sits overnight, it take several tries to get it to start. I decided to perform a fuel pressure test today. As I suspected, I was getting no fuel pressure when the key was turn to ignition ON position. Only when the engine is running, I was getting 60 psi. Immediately after the engine is shut off, the fuel pressure is dropped to zero within 2 seconds.

Through researching, I think the problem is the entire fuel pump unit. Has anyone have a similar issue where fuel pressure drops this fast? What are the chances that its the fuel injectors causing this? I want rule things out before replacing parts. Any advice is appreciated. Thank you.

 

Merged duplicate threads.

 

This happens when the check valve in the fuel pump assembly leaks and prevents the fuel lines from holding pressure. Until the pump assembly is changed, you can turn the key on then off several times before attempting to start it. Doing this will prime the lines with pressure and allow it to start easier.

 

I've also tried priming the pump by turning the key on and off with the fuel pressure gauge attach. Each time the fuel pressure would only increase by 1 psi and immediately drop back to zero. I have a leak, however I don't smell fuel or visually see gas leak externally. So what you are saying is the check valve is more suspected than the fuel injectors? Thanks for the replies.

 

That is correct.

 

I really do appreciate the replies Alloro. I will pull the fuel rail to confirm no leaks are coming from the injectors. Next, I will attempt to replace the fuel pump assembly. I will report back once it's completed.