Need Off topic help

[Chevyboy_0]

Hey guys, I need some help with a Jeep, I know its not an International Motor but I figure someone could help me. My girlfriend has a 2000 Jeep Cherokee, it has the 4.0L Inline six in it, this morning she went to start it up to go to school, the batt was dead, later today she jumped it and it fired right up then the motor died almost right away, so she jumped it again, it started up and then it died again after about 5 mins.

After work today I came over and went and it fired right up and I drove it around the block and didn't notice much till the motor started to warm up, once it hit the operating temp which is about 210* I started to notice the motor hesitate and slow down to about 300RPM. once it slowed down the motor started to lope like it was staving for fuel and reminded me of a Big Block with a radical cam in it.

I noticed that the Voltage was normal around 14 volts, and oil pressure was good, We have 2 theories one being a bad Alternator the other being a bad Throttle Position Sensor. Does anyone have an idea as to what might be the problem?

Again I know this is a 6.9 or a 7.3 but you guys know what your talking about and I need some help with this.

Thanks

 

[Knuckledragger]

If voltage is good, alternator is OK. Could be a clogged fuel filter. They will run and die like you describe, then the dirt will settle out after a while. Start it up again, the engine runs then starves out again.

 

[OLDBULL8]

Check the inline fuel filter under the car along the frame rail.

 

[1991 F350 Crew]

When you went over did you have to jump it again? I have had a ton of experiences with that era Jeep and Dodges. When the batteries die they won't run right until the battery is replaced. And even when it is, they have to "re-learn" their idle and such. I'd jump them with no throttle and they will fire and stall a couple of times, then have a very low idle. Just let it run for a while with a battery with good voltage and you should be good. Unless there is something else going on.

 

[Agnem]

A bad alternator would be easy to discover with a volt meter. If it has fuel injection, it should have a schrader valve. Find it when it dies and see if you can get fuel right away when you turn on the key.

 

[Chevyboy_0]

When you went over did you have to jump it again? I have had a ton of experiences with that era Jeep and Dodges. When the batteries die they won't run right until the battery is replaced. And even when it is, they have to "re-learn" their idle and such. I'd jump them with no throttle and they will fire and stall a couple of times, then have a very low idle. Just let it run for a while with a battery with good voltage and you should be good. Unless there is something else going on.

When I went over I did not need to jump it, I just turned the key and within 2 cranks the motor fired. So what your saying is that when the battery goes dead the ECU needs to "Re-Learn" the correct idle? So the remedy would be fire it up and let it idle for a while be it will even out? I'm gonna replace the fuel filter(s) just to be safe.

 

[Optikalillushun]

id also thoroughly clean the battery cables and any end u can easily get to. we have this problem a lot at work. irratic no starts and it turns out the battery cables are corroded even though we clean em at each service.

if u can, load test the battery after giving it a charge.