I have a 4.0 1997 jeep cherokee with 202,000 miles on it. Recently it has needed extended cranking (2-5 seconds) to start. It will also idle rough for a few seconds after starting and then it clears up and runs like it always has. I’ve changed the spark plugs and replaced the fuel filters on the fuel pump. I’m considering something with the fuel pressure regulations system or the crankshaft position sensor. Anyone have ideas or dealt with this before? Thanks
The next time you go to start it, turn the ignition switch to the run position so that the dash lights come on for two seconds, and then turn the ignition switch off. Repeat this a half dozen times and then try starting the engine. If the engine starts right up and runs smoothly the problem is most likely with fuel pump anti drain-back valve.
I tried the short on/off run position 6-7 times before starting and didn’t notice too much of a difference. However when I left it in the on position for 10-12 seconds before starting it was noticeable faster and didn’t had the short rough idle. So do I need to replace the whole fuel pressure regulator or do they sell the A-D valves separately. Thanks for the info!
Not the fuel pressure regulator, the fuel pump. In the gas tank. That’s your issue.
Sorry…I thought the fuel pressure regulator in the jeep cherokee was located on top the of fuel pump in/on the gas tank (I dropped it previously to change the fuel strainer). I wasn’t talking about the fuel pressure rail in the engine bay. I’m just not sure where the A-D valve is located.