coloradojeepxjowner

Two mornings now my 02' grand cherokee with the 4.0 liter in wont start. Now the temp says -9 degrees this morning but she just cranks away. I feel that it is a electronic/computer problem. When I turn the key on it the gas says empty, the battery gauge says below normal. And the light with a key and a slash though it stays on. Now I know it has gas cause yesterday when it didn't start I thought someone stole my gas overnight. So I brought Jerry cans from work and put five gallons in, then when I went to start it the gauge now showed 3/4 of a tank. And she fired right up.
But this morning it says empty again. When I crank on the starter it cranks fine, doesn't sound weak at all. Just no fire

dave1123

Hey, guy! Nice to talk with you again. Little nippy out there in Colorado, is it? I think it's coming my way.

I think you should check the battery supply wire to the PCM. If it's molded into the cable end, it may be loose because of the cold. This will cause a voltage drop throughout the circuit. Try a good jumper wire and see if the guages and lights work right. The battery seems to have enough juice to crank the engine but it's not getting through to the rest of the system.JMHO

coloradojeepxjowner

The PCM is located on the firewall on the passenger side? The wire harness from the battery was replaced recently when the wires corroded about a month back.

coloradojeepxjowner

I will check all the wire connections when I get home today.

dave1123

My Bad!! I meant the PDC. You know, where the fuses go! LOL@ME. I'm talking about the 4 ga. wire that comes off the battery and goes to the PDC. (How stupid of me)

coloradojeepxjowner

I will check that, maybe the jeep dealership didn't tighten everything down when they replaced that harness here last month.

coloradojeepxjowner

Checked the wiring, everything is tight. And again the damn thing starts when I get home. The temp got up to 23 today. I am gonna steal my wife's spot in the garage tonight, maybe it will start in the morning. Maybe I will throw a block heater in it tonight....

dave1123

You can throw an electric blanket over the top of the motor to keep the electronics warm. I've used that when I didn't have a block heater. My wife didn't appreciate it however. But now I have a twin bed blanket just for that purpose. She insisted I keep it!

She really got annoyed when I used one of her old pots to boil my motorcycle chain in oil. I really thought she was going to leave then. She really didn't care about the pot. She just thought I should have asked!

Just one of the speed bumps of marriage.