I attached a small transfer pump to my 2001 XJ’s battery to pull gas from a generator and into a fuel can. This took all of 3 minutes. I attempted to start the truck, and got nothing but ”tic tic tic tic.” So I had my neighbor come over to give me a jump. I turned the key and it didn’t want to start. I pumped the accelerator a couple times and turned the key again wile lightly pumping the pedal and eventually fired up as I lightly rev’d, but died as soon as I removed my foot from the accelerator. I fired it up again, gave it a couple revs, release the pedal…it died. I did it once again, but this time after it started I just maintained a steady hold on the accelerator at about 1500 rpm for a minute, then it stayed on. I drove off about 8 miles, stopped, started it normal once to check on another unrelated issue…and it fired up and ran fine during the minute I had it on before turning it off. 5 minutes later, “tic tic tic tic,” as expected because the battery wasn’t given sufficient time to charge, but I also had the same problem getting it to stay on once jumped. What could this be? My guess is a dying alternator. I've had no issues with starting and staying on before.

2001 XJ
185,000 miles
probably original alternator

 

you know mine did the same thing for a while. it started in the winter and i thought maybe it was to cold, but then when the heat came around it did the same thing. its almost as if when the enigine is warmed up, its starts fine. but when dead cold you have to idle it. I ended up putting a small nut on the throttle. it now idles at about 700-800rpms but it starts and stays on.

 

Does your XJ have a TPS?
Does your XJ have a IAC?
Does your XJ have Fresh Ground Connections?

 

The battery is just still dead.

Charge the battery over night on 2amps. If that doesn't fix let us know and we'll go from there.

 

I'll do that, but the question would be, why is the battery dead to begin with? There's no way that tiny pump (Mr. Gasket #12S) should have been able to kill the battery in that period of time.

Throttle position sensor? I don't know. I'll have to check.
IAC? Again, I don't know, but I will check and see if it needs cleaning.
Fresh Ground Connections? Is that a technical name of something or are you asking if the all the ground connection and been cleaned or replaced? They have not been cleaned or replaced.

I will add one other factoid about my vehicle. It's idle hasn't been very steady for some time now. It has a small fluctuation of about 50 rpm or so....just enough to see the needle on the gauge moving.

 

Go do a proper reload of your battery and have it load tested. This all started after you drained it with the pump, so go from there.
The rough idle can be a few things, we'll get to that once the battery is dealt with.
And it is possible that the battery might be just good enough to get you started, but weak enough to cause issues after this.
Let us know how you go.