Hello, I drive a 2001 Jeep Cherokee XJ with the 4.0 motor, and 214k miles automatic. I have heard things about the dreaded fuel pressure drop which causes you to have to turn the key 2-3 times to get it started, which my Jeep just developed after I changed the fuel tank gasket due to evap code leak. So I have been told it could be my fuel rail leaking, or the check valve in the fuel pump. Well today, as I was going about my business, I turned my Jeep on on the 3rd try, and my check engine light started to blink. So I ran the codes and they were misfire codes for cylinders 5 and 6. Could this be because I need a new fuel pump completely? I assume my fuel pump isn't getting fuel to the engine like normal because the cylinders are firing off beat. How could I fix this? By changing the whole fuel pump? Or do I have a bigger issue?

 

test the fuel pressure with a gauge you can borrow from a parts house.

 

Okay great, where would I test the fuel pressure? On the fuel rail?

 

Yes. There is a fitting on there.

 

Okay, what should the pressure be running at when it is off and on?

 

http://www.underhoodservice.com/tech...uphill-battle/

 

Do Like this vid.

 

okay so I tested the fuel pressure on the rail and it was running at 50psi which is what it's supposed to be, then I cut it off and I know it's supposed to stay at 24psi for at least 5 minutes, but the gauge went right to 0. Now I looked at all the injectors and there is no visible leak and no smell of gas up in the engine compartment. The fuel pump hums before it starts so I'm guessing the sending pressure from the pump is good, but what's supposed to hold it in the rail isn't good. It sounds like either the check valve is bad or I've heard it could be the fuel filter but they are a part of the fuel pump so I'm not sure what's the issue

 

Bosch 67658

http://www.rockauto.com/en/catalog/j...assembly,10147

 

Time for a bluetooth sender unit and smartphone software to fit that fitting... What do you think? So it can be monitored while driving and differing load conditions

Thank you my friend for your kind words when I came back. Just needed to let you know I did catch that Cruiser and appreciate it very much Sir.

 

what??

 

They have wireless bluetooth technology for our code reader plug that works with a smartphone, quite well actually and cheaper than a code reader. Why not make one that taps the fuel line in systems that do not have a pressure sensor so that it can be monitored in real time while driving it under load and Etc. Having proper pressure sitting at an idle is not always accurate to what you might be getting under load and high flow conditions.