99 XJ 4.0L with 147k miles.

Having kind of a rough idle so i thought i do a fuel pressure test and here is the result.....i sure something is wrong.

Fuel filters and regulator was replaced less than 1000 miles ago.




Please advise.
Thank you.

 

Anyone?

 

Fuel Pressure Regulator Operation: The pressure regulator is a mechanical device that is not controlled by engine vacuum or the Powertrain Control
Module (PCM). The regulator is calibrated to maintain fuel system operating pressure of approximately 339 kPa (49.2 psi +/- 5 psi) at the fuel injectors. It contains a diaphragm, calibrated springs and a fuel return valve. The internal fuel filter is also part of the assembly.

 

Thx for the reply but i'm not understanding

 

It looks like its ok... (49psi +/- 5 psi) but I dont think it should be jumping that much.

 

How's it idle now? better? Is your regulator adjustable? I don't think fuel pressure at the top end of the specs would be a bad thing.. long as it isn't leaking.
You might also check the return line.

 

Idle fine with a little rough when idling, before and after the regulator replaced, and no, regulator non adjustable.

Replacing the regulator helps with the starting of the Jeep, no more 2-3 cranks, it starts right up every time.

I'm just trying to find the problem with the rough idle......might have to check the exhaust manifold/gasket.

As long the bouncing is normal i'm just gonna move on.