98xj

So I ran the truck through a carwash, and got the undercarrige sprayed. 10 minuted later I'm broke down in an intercection. The voltameter was reading 0 and my radio wouldn't come on. Engine was running and revving but had 0 power. Couldn't even move out of the intersection.
Now battery acts dead and engine won't turn over. Had to arrange rides home for the fam, so I haven't had a chance to look at it at all.
Of course its sitting there with 60bucks of gas I just put in it.
It backfired a little before it started dying.
Any thoughts?
Distibuter got wet? Alternator suddenly failed? O2 sensor maybe?
It started right up this morning and I ran it through a buncha puddles and all was fine.
Help!

 

My first look would be the alternator personally

 

x2. Especially if it's the original alt. IMHO, the alternator for the XJ isn't in a smart location. Right near the ground, and soaking it can mean its demise. But, you said the Volt meter just dropped off? That is strange, as seeing even if the alternator failed, the battery should have kept 12 volts until it drained shouldn't it?

 

X3- and do most people move them??? Where 2 and how??? Cause I would like to move mine.

 

Yeah I peeked under there and if that's not the original alt then it has had a hard life.
Imma test the battery tomorrow and try and jump it just bin case it was water.
I'm scared it has fried things. The volts dropping off and my radio not coming on worries me. Also....wth~ if I can't go through some puddles in my yard how do people mud these things!

Lol.

What's a good alt? Also....if I change the alt are there other things recomended to do while its off? Belt? Compressor? Upgrade the wiring back to the starter? Prolly all of the above.

 

Make a big a$$ splash guard out a a truck mud flap. Sounds like you lost a ground somewhere

 

Yeah... I'm not too knowledgeable on Jeeps just yet. But I've had bad grounds and alternators die. If your alternator went out, and your battery was crap (end of it's life), your vehicle will fail quickly. However if your engine was still running, you were still getting juice to your plugs... Just weird. Unless your engine did eventually die, along with everything electrical (brakes, steering, radio, lights). If it were a bad ground, I don't think you'd get any power at all. Also, I believe it will still run with a faulty o2 sensor... Correct me if I'm wrong.

 

Yeah...it was still running...but with absolutely no power to the wheels. Almost like it was outta gear....but it was in gear. Just wasn't enough power to push it.
It went from driving great to undrivable with a dead system in like 10 minutes. I just don't get it.

 

I had a guy ask me to look at his jeep once. It had dim lights everywhere, ran like poopoo and started kinda funny. It has a bad ground right where the negative battery cable attached to the body. You might consider that your alternator went south and shorted out your battery. Try unhooking the alternator and jumping the jeep with a battery charger and leaving it attached if it starts. It would deffinately be a shorted out alternator at that point

 

Now that I see you have a 98, your voltage regulator is built into your ECU and getting it wet could definately cause you a problem... or 100

 

Well,
I'm going to get out to at this afternoon...hopefully my bfg's are still on it when i get there!

Can I do that old trick where I jump it off, then pull the battery positive off? I know some cars you can't do that anymore.

I've got a sneaking suspicion ill be having it towed to a mechanic. Mostly cause that's how things go for me.:banghead:

 

Absolutely not. Do not try this! I used to do this 30 years ago on my 66 Chevy, but the technique isn't safe any longer.

Spikes and transients can ruin anything that has solid state electronics on it like the alternator and computer for starters. I personally have worked on a couple of XJs where the owners have done this and been a lot lighter in the wallet after doing so.

Here is a good article that explains why you should not do this.

http://www.troubleshooters.com/dont_...ct_battery.htm

Troubleshooting the charging system is not particularly difficult with some basic knowledge and test equipment.

 

I'm glad you posted this. I guess I was really lucky. I had an electrical issue on my rig, and asked a friend to help me replace the battery (I wasn't feelin the best). Anyways, of course this friend was my friend's stepdad, and he grew up in the time when people had the older vehicles you could do this kinda stuff with. So, after he swapped it, without any chance to say "hey, hold up a sec", he started it up and disconnect the positive cable. Now, idk if I got lucky because mine is a '91 OBD 1 or what, but luckily after reading what you posted, I had nothing happen. I will be sure though that it doesn't happen again.

 

as for disconnecting the battery to test, I will mention 1 weird fact, I know some motorcycles if battery is disconnected they shut off, even though the charging system is fine, I found out the hard way when a cable broke from vibration & it shut off, & playing with it, & later working at a bike shop. so every thing would be fine, but it will cut off when battery is disconnected, & has to be trouble shooted with a meter.

unsure if any automobiles work the same, because of the electronics, I never tried

 

Good call.
Well I'm going to poke around a bit then and see what I find. I call myself an electrician at work, but low voltage isn't my thing. I'm going to try to jump it first to see if it was just a wet distributor/alternator.