Voltage meter still below 14 after new battery & alternator - Page 7 - JeepForum.com
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post #91 of 96 Old 06-15-2012, 10:31 PM
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Originally Posted by ratmonkey View Post
One of the problems we're having here is that you are using incorrect terminology. Luckily, we can catch your meaning on most of this. But i still have no idea what 30a circuit you needed to buy on Ebay.

Technical discussions require precise technical language to hold meaning and actually end up at correct solutions.
is this normal

14.01 volts at start in the morning
13.88 volt after I drive for 30 mins
13.77 volts after I turn my car off and back on
13.00 volt with wiper defogger head lights flasher on radio on.
12.40 volts in reverse then back up to 13.28 in drive
12.75 volts in idle.

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post #92 of 96 Old 06-16-2012, 08:19 AM
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I just read your entire thread.
Ratmonkey is right in saying the terminology your using is a little confusing when your trying to troubleshoot electrical problems.

Voltage is the potential between the - and + of the battery, that should be 12v, 2v for each cell in the battery.
Mostly, everything in the vehicle needs that potential to operate at it's designed inefficiency.

Current (amps) is the working (power draw) part of electricity. When you multiply the amps times the voltage you get the Wattage that is being used by a particular part of the circuitry.

A 30 amp circuit is just that! A circuit that is designed to supply and protect a circuit that has the potential to draw 30 amps of current at 12 volts. If the circuit draws more that 30 amps as in the case of a defective part or a short, the fuse will blow. That leads me to a question.


New battery, cables, ECU, good grounds,...smoke? Electrical? or engine?

At idle, with all of the accessories off, the voltage output of the generator should be around 14v. At that time it is also charging up the amperage that is lost during the high draw operations. If the accessories are still on (air conditioning), the low speed of the engine might still be showing you a 12-14v supply being produced, but the amperage is being sucked out of battery.

Is the ac still on when you have not selected it? It will slow the engine down causing the generator not to put out what is needed to charge the battery, plus it will suck the current out of it too. If the ac is on remove the connector on the compressor to see if what your looking for gets better. Any charging above 12.5 is good, but normally 13-15v is what would be considered optimal.

It might be a good idea to start pulling fuses while the engine is at idle just to check what is pulling so much current that it will take down your battery.

Here is the info for that b7 connector there should be 8 volts for the sensors. Why are you asking that question?
Attached Thumbnails
b7.PNG   b7a.PNG  
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post #93 of 96 Old 06-16-2012, 04:46 PM
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I was wondering how do I remove a belt pully on my alternator it does not fit my belt, I need to to remove my old pully from the old alternator and put it on the new 130 amp alternator.
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post #94 of 96 Old 06-18-2012, 10:59 PM
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just for anyone who has the problem's I've had please check the following wires battery ECU and make sure you have the right alternator installed because I spent 3 years with a voltage problem and went through 6 alternators 4 ECU a wire harness 3 battery's and a whole fuse system and spent a total of 1500.00 on a mistake of installing a 90amp alternator which was the problem all a long not the ECU not the battery and not fuses, or wiring for that matter, it ended up being the wrong alternator the 94 Grand Cherokee should have 117amp or higher the 90amp does not work in this car, I installed a 130amp and I am getting 13.77-14.1 volts all the time now, make sure you have a 7ribs pully not 6 rib also buy a volt meter and check voltage make sure you do not do what I do.
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post #95 of 96 Old 01-09-2016, 04:04 AM
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Edit nevermind just seen the age of this thread.
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post #96 of 96 Old 01-09-2016, 08:17 PM
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one word get a new ECU.
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