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Nova Wake
February 1st, 2010, 19:11
Ok now my jeep is on the side of the road away from me for the night but here is the problem.

About three months ago my check engine light came on and i lost all power to my jeep and it stalled at an intersection, i rolled it to the side of the road and tried to start it again about 10min later it started fine and there was no cel anymore. Ok its been fine for three months.

resently the cel came back on, and stayed on for a day go away for two and then stay on two days. And if i let it sit for two days my truck wouldn't like to start, it wouldn't get any power no buzzers no lights nothing, then leaving the ignition on for a min all power would restore and be fine the rest of the week. But today, everything got real dim and then dimmer and the nothing. Jumped it once lasted about 200 yards before it stalled, jumped it again stalled in another few hundred yards, everything would get dim dimmer and the nothing. Tried to jump it a third time and didn't want to start at all, lights still on but so dim barely visible. turning the ignition it would try turn over and then just click repeatably. Also my radio would turn on and off, on and off. And my heat would only work on high but it sounded like it would fluctuate the amount of air it would blow.

95 jeep Cherokee automatic 4,0 194,000 miles
I did smell plastic or rubber burning once maybe twice but didn't take alarm and may be unrelated. Now my question is is it the alternator? or is a cell blown in the battery? or other? does a bad battery throw a cel?


if its the alternator what tools precisely do i need to do a side of the road repair?

Nova Wake
February 1st, 2010, 19:38
is it the alternator?

ehall
February 1st, 2010, 19:48
sounds like battery is toasted, probably have a bad wire and/or terminal

try a known good battery, clean the terminals, check the wires

my2monkeys
February 1st, 2010, 19:49
Probably the alternator. A basic socket set with metric sizes will get it done. Sounds like you might need a new battery now, as it was completely drained when alternator was out. You don't want to employ the new alternator with a weak or dead battery, this will harm the new alternator. Good luck.

blondejoncherokee
February 1st, 2010, 19:56
tools for the alt: basic wrenches and sockets. super easy. loosen the tension on the belt( on my renix its the ps pump, not sure about the HO) then take off the electrical connectors and tbe 2 bolts that hold the alt. on. swap in new alt. grease up bolts, and reinstall. dont over tighten the belt either. youre done. maybe 15-20 mins? thirty if you dont know what youre doing. you could pull the alt first and have it tested too before you buy a new one , but i also think it sounds like an alternator. i know on the renix one bolt is 13mm and the other is 15mm. the positive battery terminal nut on the back is 10mm. the ps pump bolts are all 13mm as well(on the renix)

joe_peters
February 1st, 2010, 21:10
1. Doesn't matter if it is the alternator, cables, or battery, or some combination.

2. Get a fully charged battery, install it. Clean the cable ends when you do this.

3. Drive it to someone that knows what they are doing--you ignored plenty of warnings to land yourself in this situation.

Matthew Currie
February 1st, 2010, 21:47
Have you tried to get the CEL code? Not much point in OBD if you don't use it.

Check the wires and the battery itself first. Make sure the braided wire that connects the rear of the valve cover to the firewall has not turned to dust. It's easily missed. Test things. Don't just throw money and parts at it. Alternators are not cheap enough for testing by substitution.

Get (buy or borrow) a battery with juice in it, make sure it's actually well connected, and read the code. (engine off, ignition only, key on, key off, key on, key off, key on - and then watch for blinking lights. Each code is two blinked digits. Expect 12 for recent battery disconnect, and 55 for end of sequence. All other codes are trouble. Get them on the net or post back here. )

If it was intermittently dying then restarting, I doubt it's the alternator, especially if nothing showed on the charge light or voltmeter. Or at least I doubt it was the alternator when it first occurred. What's wrong now is more difficult to say.

If you boost a bad battery in an XJ or other vehicle with Mopar fuel injection, it will run very badly at least for a while. They're sensitive to the bad voltage and unfiltered alternator output that come when the battery is not properly taking a charge. So even if you do get the charging working, and then start it with a boost, expect it to run lousy for a while until the battery stabilizes. If the battery is really bad, it will not run well until you replace it.

orange
February 2nd, 2010, 01:42
X2 Joe's post.

Should run long enough with a good battery, fully charged, to get to a place to repair it (a few miles) if cables ok and clean connections.

Nova Wake
February 2nd, 2010, 14:52
Ok wasnst fun but did a roadside repair in 20 degree weather in the snow, replaced the alternator and battery, Engine light is now gone and it ran fine all day. i did bust the hose on the air box that goes to the engine and ill need to replace. Ehe heater only works on high but i think that that little 4 pronged thing under the glove box went bad. Idles at 11, and when driving im at 14 on battery.

winterbeater
February 2nd, 2010, 16:29
Sounds good. And you are right in that your blower motor resistor probably blew the thermal fuse. During tests, we found that the the resistor was under more stress when forced to run at lower voltage. Watts = volts x amps, so to get the work done at lower volts draws more amps and as you know, fuses work (blow) on more amps.

One more reason to turn your HVAC off when parking so that key on, with the starter drawing down voltage too, the blower motor won't be trying to draw more amps over the thermal fuse.

And high bypasses the resistor and thermal fuse completely, as a safety factor to make sure you have defrost.

orange
February 2nd, 2010, 17:36
"Idle at 11" - does NOT sound good! ???

Matthew Currie
February 2nd, 2010, 18:08
"Idle at 11" - does NOT sound good! ???Depends on where the measurement comes from. If he's running the fan on high and the dash voltmeter says 11 it may just be the fault of the voltmeter.

I agree, though, that a battery reading should show 14 at idle, and it would be a good idea to get that reading with an accurate meter.

Nova Wake
February 3rd, 2010, 16:03
the fan is on high and when stopped it falls only about two points, it looks to me as if its at around 12, if im costing and not hitting the gas it stays at 14 never below, only when im stopped dead still.

winterbeater
February 3rd, 2010, 16:09
Back to testing voltage at the battery again. A common recurring theme. Multimeter on battery should read 14. The in dash voltmeter is not in an effective spot in the wiring.

But...........if it's all still working and starts up after you turn it off, it can't be too bad.

joe_peters
February 3rd, 2010, 17:44
At the battery with a voltmeter:

Static voltage 12.5 (static means engine off, zero load); engine running, at idle, 13.6~14.5 volts (no load). If you don't have that, fix the problem.

Nova Wake
February 7th, 2010, 04:00
with nothing on no heater no lights it idles at over 14.5, close to 15, driving it increases a tiny bit. As soon as i put the heater on its highest setting it dropped to around 12.5, high beams drop it to around 13.5.

The heater blower resistor is blown i believe, and it only works on high, the amount of air being blown fluctuates. If im stopped it blows slower than if im driving.

Matthew Currie
February 7th, 2010, 06:05
with nothing on no heater no lights it idles at over 14.5, close to 15, driving it increases a tiny bit. As soon as i put the heater on its highest setting it dropped to around 12.5, high beams drop it to around 13.5.

The heater blower resistor is blown i believe, and it only works on high, the amount of air being blown fluctuates. If im stopped it blows slower than if im driving.If that's with voltmeter at the battery, you have a problem. First thing I'd do is double check that the wiring as good and connections solid. And of course you need to make sure the belt isn't slipping. If everything is good, then it sounds as if your alternator is not putting out sufficient current, or at least it's not getting to the battery.

If you just put in a new or different alternator, perhaps it's defective. If you can, try taking it out and running it in to B&B Auto Electric in Rutland. They'll test it.

There's definitely something wrong here.

winterbeater
February 7th, 2010, 06:43
In re-reading this thread, I miss any indications that you disassembled, cleaned, and securely reassembled all connections between the alternator, battery, engine and body. This includes all ground connections. The wiring is only half of the circuit. The other half is the engine and body. A weak ground or other connection can choke down the current from the alternator to the battery. You must have the complete circuit.

orange
February 7th, 2010, 09:41
A voltmeter means a hand held testor to read the volts at the battery terminals ON the battery.

Also known as a V-O-M or multimeter. 'bout 10-20 bucks at the store for a good one (more expensive not needed).

-----------

The grounds MUST be disconnected and cleaned. "Looks OK" means nothing as just the thinnest film of corrosion can be a non-conducting connection. Cables and wire can be eat up inside the insulation and 'Look' OK on the outside.

Testing is the best way to verify all is well. A multimeter is Very useful.

If your battery cables are green and corroded where they connect to the "clamp" end that attaches to the battery, they are suspect.

Remember that a circuit is hot(+) going out, and Negative coming back and BOTH (+,-)must be good to work properly.

(a 6 volt drop in (+) going to a headlight = dim light. OR a 6 volt drop on (-) ground side will also = dim light.

orange
February 7th, 2010, 13:03
X2 with winterbeater

joe_peters
February 7th, 2010, 20:22
Winterbeater and Orange have it covered, only thing I would add is make sure the battery is fully charged and then have it load tested. Overcharging could be an indication of a failing battery.