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Discussion Starter · #1 ·
Over the past couple days my '89 2.5L has been starting up oddly. It cranks over but seems to have trouble turning over, but just as it sounds as if the battery were about to die and you'd hear clicks instead of the engine turning over it fires up and comes to life. You turn the key and it turns strong then fades as if the battery were not keeping or holding a charge and sounds like its about to not start. I went to charge the battery last night and hooked it up to my trickle charger and it showed "charged" on the indicator.

The dash lights come on full brightness and the headlights work with just the key in the on position. Fuel pressure seems to be ok as once it catches it fires right up strong. Could this be the alternator or is it the starter? I'll check my connections this weekend when i have some time.

Any thoughts what this could be?
 

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The easiest thing to do is to remove the battery and alternator and take them to be tested at your local auto parts store.

If they test good, put them back and pull the starter. Take the starter in to be tested. From your description of symptoms, I suspect the starter but I would do the easiest things first. If you feel particularly energetic, you can take all three in at the same time.

Parts store tests aren't always 100% accurate, but unless you have your own high quality test equipment, the parts store tests will give you an idea of where to look.

Good Luck, L.M.
 

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Clean terminals. Most of them have coating on them from the factory (aftermarket replacements, of course) that prevent good connections.
 

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Discussion Starter · #4 ·
Can they test the alternator and battery while its in the vehicle? starter as well? Also, will the 89YJ starter fit other year models?

Thanks!
 

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I've never tested an alternator before (at a parts store) but I'm sure it has to be out of the vehicle. Starter definitely has to be out of the vehicle. Battery can be left in the vehicle.

Starters are pretty much the only parts that aren't compatible year to year. They differ greatly, depending on the flywheels.

The starter test is not accurate at all. I've replaced three starters that are bad, but they all tested fine... I wouldn't recommend relying on it.

Keep in mind that you're taking a part out of the normal environment it's in where the issues are occurring. Without perfectly replicating the vehicle conditions, you won't get a good test.

You're better off underneath the Jeep with a test light on the solenoid power wire. Have someone turn the key to start it. If there is power to the test light, but no crank, starter is bad.

Given your conditions I'd be surprised if the starter is bad. You likely have...
1. Bad alternator
2. Bad battery that is just discharging any sort of charge applied to it (seen it before)
3. Other issue

Put a multimeter on the battery. Should be charging at 14V. Wait for your issues to occur, and see if the voltage drops. If it does, then you want to run a voltage drop test on the alternator power wire and positive terminal, and then the engine ground and negative terminal.

The idea of a voltage drop test is that any resistance on the circuit will draw voltage.
 

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'89 YJ 4.2 with MC-2150 Carb & HEI, 2-1/2" Ex. AX-15, NP231 SYE, Adams shafts, F&R ARB, 3
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Does it start right back up after you've driven it and start it shortly afterwards?
I wouldn't count on your trickle charger to give you a true read. I had a motorcycle battery go completely dead, wouldn't take a charge but the charger had the little green light saying it was charged.
Could just be time to replace a tired Battery if it hasn't been replaced in the last couple years. Here in AZ I can count on replacing batteries in almost all my cars every two years at the beginning of each summer, 2 so far this year already.

Good luck finding the issue.
 

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Over the past couple days my '89 2.5L has been starting up oddly. It cranks over but seems to have trouble turning over, but just as it sounds as if the battery were about to die and you'd hear clicks instead of the engine turning over it fires up and comes to life. You turn the key and it turns strong then fades as if the battery were not keeping or holding a charge and sounds like its about to not start. I went to charge the battery last night and hooked it up to my trickle charger and it showed "charged" on the indicator.

The dash lights come on full brightness and the headlights work with just the key in the on position. Fuel pressure seems to be ok as once it catches it fires right up strong. Could this be the alternator or is it the starter? I'll check my connections this weekend when i have some time.

Any thoughts what this could be?
A battery can say good on a charger but when put under load it will fail quickly. If you put a meter on it will show 12-14 and under load drop to 3-4-5. This usually means there is a bad cell in the battery.
 
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