Jeep dies or sometimes won't start.

[natebivens]

I have a 2001 jeep grand cherokee, with a 4.0 powertech I6. The engine will sometimes die while at an idle. Or, it won't start if you don't get it started on the first try. If I wait for about 30 minutes, then it will start. I bought a fuel pressure gauge and checked the pressure. With the key turned on pressure comes up to 45 lbs and then bleeds down very slowly. I waited for about 5 min. And, it bled down to 39 lbs. When i started it the pressure came up to 44 lbs. But, the needle was jumping like crazy from 44-41 lbs. Do I have a bad regulator? Or should I change the fuel filter first?

 

[TerryMason]

I'd start by pulling any codes from your Jeep that you can. Either do it with the key, or take it to the local parts shop.

 

[Dragon5126]

Terry is correct. ANY computer controlled vehicle that wont start like this should always be checked for error codes first. they may tell you exactly what is wrong. With that said... the pressures listed are low for a fuel injected vehicle. The computer may tell you why. If it doesnt then you ALWAYS trouble shoot with the KISS principle . Do not be offended by the explanation. KISS stands for Keep It Simple Stupid. This means always start with the most simple possibility first and then climb the ladder. most simple after asking the computer to tell you whats wrong? the fuel filter (there is a slight problem you may face on the fuel filter as is noted ahead). Next is debatable depending on who you ask, and your vehicle it self pressure regulator or fuel pump... if the regulator is easier to pull and check than accessing the pump you check the regulator if not then you go for the pump. I dont know your specific vehicle but I know chrysler... they mostlikely did not put an accessport in the floor of the body above the fuel tank to get at the pump which is located inside the tank (and probably also has an internal fuel filter as well) so that means you will need to drop the tank... and skid plate.... Oh how I long for the old ways of automotive engineering!