98 blazer battery problem
#11
11-08-2012, 05:07 AM
I agree with captain, you come here looking for help and he gives you ideas to try and you decide to toss 220 dollars into it without diagnosing it. Not trying to be rude or anything, but you should diagnose it first.
#13
11-08-2012, 05:58 PM
well no ive been looking into a new alt for some time now i was just waiting for it to go out i wasnt waisting any money like that until it happend. but today i got out of work when it was dark so i couldnt work on the truck but i did let it warm up and unhooked the positive cable from the battery to check the regulator and the truck kept running so im sure its something else.
#14
11-08-2012, 08:10 PM
Not a good idea to disconnect battery cables while the engine is running. It can do permanent damage to the electronics. Check the voltage while it's running, & post what you find.
#15
11-08-2012, 09:22 PM
oh i didnt know that i turned everything off im not sure if that helps. but ill have to go buy a ohm meter tomorrow when i get out of work. it started today but it acted like it did not want to just barley cranked over.
#17
11-09-2012, 05:49 PM
Woops! Thanks for correcting my spelling 
How to check parasitic draw:
Make sure the ignition and all accessories are turned off including the dome lamps, glove box lamp, phone charger, power inverter, etc, everything must be turned off.
Disconnect the negative cable at the battery and leave it disconnected for at least 2 to 3 minutes.
When power is restored to the memories, there is a substantial amperage surge, (spark) to energize the various keep alive memories in the vehicle, (PCM, BCM EBCM, clock, radio, key FOB receiver, remote start receiver etc etc). This surge must not be allowed to pass through your DVOM, (Digital Volt Ohm Meter). It would most likely pop the internal fuse, or cause the magic smoke to escape from your DVOM... instantly. To avoid this, the memories must have battery voltage to them, and amperage draw must be stabilized, before parasitic draw is checked. With the battery cable removed, put a short bolt in the negative terminal of the battery. Then peel back the rubber insulator on the negative cable end to expose the eyelet. Connect a 10 gauge wire, (maybe a foot long or so), from the bolt to the eyelet. There will be a spark to energize the memories. These two connections must be tight, I use a vise grip on each end. Do not operate the starter unless the battery cable is connected to the battery. Wait approximately 5 minutes for all of the memories to energize and stabilize. After they stabilize, the combined amperage draw of the memories should be under 1 amp.
Set your DVOM to the "DC AMP" scale. Most DVOM's only have a 10 amp maximum testing capacity. Connect the test leads to the "COMMON" and "DC AMP" receptacles on the DVOM. Using alligator clips on the probe ends, connect one probe to the bolt in the battery, and the other probe to the negative cable eyelet. Polarity doesn't matter as the DVOM will detect it. Disconnect one end of the 10 gauge wire and read parasitic draw on the DVOM. Maximum allowable parasitic draw varies on vehicles, but the standard rule of thumb is less than ~1200mA. The higher the draw, the quicker the battery will discharge. If draw approaches 1 amp, it will discharge a battery in ~30 hours.
If the draw is excessive, start pulling fuses, one at a time, until the draw drops to an acceptable level. Remember to close the doors if you get inside the vehicle to pull fuses. When the draw drops, you've found the circuit that's causing the problem. Best to get a schematic and start hunting
In a nutshell, that's it. You can probably find more using a Google search.
How to check parasitic draw:
Make sure the ignition and all accessories are turned off including the dome lamps, glove box lamp, phone charger, power inverter, etc, everything must be turned off.
Disconnect the negative cable at the battery and leave it disconnected for at least 2 to 3 minutes.
When power is restored to the memories, there is a substantial amperage surge, (spark) to energize the various keep alive memories in the vehicle, (PCM, BCM EBCM, clock, radio, key FOB receiver, remote start receiver etc etc). This surge must not be allowed to pass through your DVOM, (Digital Volt Ohm Meter). It would most likely pop the internal fuse, or cause the magic smoke to escape from your DVOM... instantly. To avoid this, the memories must have battery voltage to them, and amperage draw must be stabilized, before parasitic draw is checked. With the battery cable removed, put a short bolt in the negative terminal of the battery. Then peel back the rubber insulator on the negative cable end to expose the eyelet. Connect a 10 gauge wire, (maybe a foot long or so), from the bolt to the eyelet. There will be a spark to energize the memories. These two connections must be tight, I use a vise grip on each end. Do not operate the starter unless the battery cable is connected to the battery. Wait approximately 5 minutes for all of the memories to energize and stabilize. After they stabilize, the combined amperage draw of the memories should be under 1 amp.
Set your DVOM to the "DC AMP" scale. Most DVOM's only have a 10 amp maximum testing capacity. Connect the test leads to the "COMMON" and "DC AMP" receptacles on the DVOM. Using alligator clips on the probe ends, connect one probe to the bolt in the battery, and the other probe to the negative cable eyelet. Polarity doesn't matter as the DVOM will detect it. Disconnect one end of the 10 gauge wire and read parasitic draw on the DVOM. Maximum allowable parasitic draw varies on vehicles, but the standard rule of thumb is less than ~1200mA. The higher the draw, the quicker the battery will discharge. If draw approaches 1 amp, it will discharge a battery in ~30 hours.
If the draw is excessive, start pulling fuses, one at a time, until the draw drops to an acceptable level. Remember to close the doors if you get inside the vehicle to pull fuses. When the draw drops, you've found the circuit that's causing the problem. Best to get a schematic and start hunting
In a nutshell, that's it. You can probably find more using a Google search.
#18
11-09-2012, 08:14 PM
thanks for the info i started the truck up after i got out of work it started up just fine just a bit slow but after it ran all day i got from point a to point b without a problem but im still going to check to see why its acting like that tomorrow on my day off.
