Jeep Grand Cherokee 2001, Rough starting

Maintenance/Repairs
1

Hey,

my 2001 Grand Cherokee is really struggling when starting. It takes about 8 or 9 seconds of cranking to finally turnover and start. Its like this in all weather cold or hot. But if I have been driving it say just down the road and to the gas station it starts up right away. Yet the second it sits for a while, half hour or more it takes a while to start. Any ideas?



Thanks for your help, Ben

2

How many miles are on your JGC? 4.7L V-8 or 4.0L I-6? How long since it had a new set of plugs?

3

Ignition parts are always a suspect with hard starting, but it sounds to me like the vehicle requires the extra cranking to re-pressurize the fuel system after sitting for a while. Check the fuel accumulator, or whatever Jeep calls that part. Its purpose is to keep from having to crank the fuel pump so long just to pressurize the system.

4

The next time you go to start the engine after the vehicle has sat for a period of time, 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 a dozen times and then try starting the engine. If the engine starts right up, the check valve in the fuel pump assembly is defective and allowing the gas in the fuel system to drain back into the gas tank.

Tester

5

It’s a 4.0L I-6, and its got about 104,000 miles. As for the plugs, I cant recall the last time they were changed.

6

Hey tried the keys on and off about 7 times and it still cranked for about 6 or so seconds. Though I did read somewhere that the fuel pump on these models had a defective seal, I guess that does make sense. Is there a way to check if there is a bad seal from the fuel pump causing it to loose pressure or something?

7

Connect a fuel pressure gauge to the fuel rail. Turn the ignition switch to the run position to build the fuel pressure. Turn the ignition off, and watch the pressure gauge to see how fast the fuel pressure bleeds off. If it takes 15-20 minutes for the pressure to bleed off, that’s normal. But if the pressure bleeds off immediately or after just a few minutes, there’s a problem with the chack valve.

Tester