Hey guys! I've got a 94 xj with the 4.0. Recently, I was doing some general diagnostics and tested my fuel pressure. At the rail at idle speed I had a steady 29 psi. According to my manual it should be 31 at idle. Would being 2 psi low cause any issues like lack of hp or low mpg?

Also, I noticed that all the replacement regulators in the stores are specified as having a 39 psi operating pressure. What's the deal with that? Thanks you in advance for your answers!

 

My .02 is you are fine. The"39 psi operating pressure" is with the vacuum line off the regulator, then you look for about 10 less with it on.

http://www.jeep4.0performance.4mg.com/tech_specs.html

 

Oh, well that makes a lot of sense. Thanks for the great info!

 

How good are the aftermarket regulators? Anybody make a good one?

 

No prob Doug, happy trails. Adam...I'm a bit "old school". I'd feel better about a regulator from the JY then a new one. That's just me though. (don't loose the spacers between the O rings on the connection!)

If your pressure is low you can crimp/squeese the rubber return line closed and see it the pressure spikes. If it doesn't, the low pressure is from something else.

 

Just putting it out there, I frickin' love this forum! There are some super smart guys on here.