Another "my jeep won't start" thread...

Alright, I could use some help on this one. Well This morning when I woke up to go to football training, the XJ (1998)...started up fine, drove fine...etc. Well I parked it afterwards and went about my normal classes for the day. Well I go to drive to work, annnnnd it won't start. I noticed that I had left my dome light on, so I figured a good jump...and i'de be good. Well I tried jumping it (Optimia Red Top)...and that didn't work. The engine without the jump, would seem kinda sluggish, like it needed more juice. Well if I give it gas while trying to turn it over, it will just roar up and revv (have to hold down pedal), but as soon as I let go...boom its dead again. I went and whacked the starter, but no difference there. I was thinking well maybe I'm low on gas...but them it wouldnt be able to roar up would it? Would it be the CPS, I hope not...(po' college student ). Any ideas or leads???

freerider15 said:

The engine without the jump, would seem kinda sluggish, like it needed more juice.

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'Juice' meaning spark or gas? Everything worked OK before the dome light was left on, yes?

Well if I give it gas while trying to turn it over, it will just roar up and revv (have to hold down pedal), but as soon as I let go...boom its dead again.

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This almost sounds like the classic shot battery / alternator issue. Mind you, it could also be fuel starvation if the filter's clogged enough.

BTW, be careful about standing on the accelerator during start-up. Uncombusted fuel can end up in the catalytic converter as a result, which will burn it out pretty quickly once it's up to temperature.

I went and whacked the starter, but no difference there.

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I've had the starter go out on me in a couple of cars in such a way that it will crank, but won't get enough of a kick to actually start. This drains the battery, which makes everything work OK on a jump... But the alternator's shot as well, which means it can't charge the battery.

I was thinking well maybe I'm low on gas...but them it wouldnt be able to roar up would it?

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Depends on how much fuel is in the bottom of the tank. As long as more fuel than air is making it up to the injectors, it'll still turn over but never catch.

In order, I'd check the following:

- Battery
- Alternator
- Starter
- Fuel filter

Would it be the CPS, I hope not...(po' college student ). Any ideas or leads???

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Possibly, but a '98 with a failed CPS would be slightly unusual. I'm kinda leaning towards the fuel filter, but since that involves dropping the tank and the other stuff can be tested without removing them from the XJ, I'd head to someone who can test them and check the filter last.

fuel pump on it's way out or the resistor wire cooked (it's bypassed while cranking) One of the other sensors gone could do it too. Try cycling the key 3 times and see if it does any codes.

Just this past week I had similar problems. Since I had a new fuel pump assembly, I was convinced it was the starter. Same thing, like it needed more juice. I also had the symptom of having to depress the gas pedal and as soon as I would let off it would die.

New starter and same problem. It ended up being the starter relay. $13 from the dealer and it fires right up.

It might be worth a start, since it is cheap and easy to replace.