voltage question - 96' C1500 5.7

[jsgold]

Our truck clicked and did not start all of a sudden this evening on the first crank. Just a couple of seconds and when I tried again it fired up. I drove it a few miles and restarted it three times. Each time it clicked then started like the battery was low all in one motion. I just brought it in a ran a couple of voltage tests on it. The battery sitting had 12.69 volts, engine running 13.4-13.6.....with all lights on 13.1-13.3 volts. Does not seem real low although I know some of these trucks usually run a little higher. I hooked up a 6 amp hr charger to it and it went up to 8 on the meter and then dropped after 15-20 seconds to 3. I charged it for about 5 minutes and repeated the tests, same thing but it did not click. It jumped back up to 8 then dropped rapidly back to three and it is on charge even now. Some of this most likely won't mean a lot and I have yet to check the cables over as it is dark but it may be a weak alternator now suppying enough amperage or possibly a weak battery. The battery is about 18 months old give or take. I don't have a factory manual on this truck unlike my others. How does the voltage sound so far???

[kahjdh]

I would do a voltage drop on both cables to and from the starter than do a current test if you can track down a big enough amp clamp.

Also what does the voltage drop to when cranking? if it goes below 9.5 the batt is weak.

[brcidd]

Could easily be the starter solinoid where the copper contacts come together. I have had several act just like yours- but not engage the starter the second time...When mine would not start, I'd get the click, but nothing else- maybe 30 mtimes in a row.

My advantage was that I have remote starters on all my vehicles, which allows me to go underneath my truck (Dually) and activate remote starter, then with a hammer, tap on starter right when I hear the click, then starter engages and engine starts. After about 3 or 4 bouts with this issue, I opt for a new starter.

Based on what I went through, a new starter was in order and curred the problem.

[j cAT]

the best way to get to the issue here is clean and check the battery connections. then have the battery LOAD tested..this will show if the battery is weak or has an open cell/internal open defect ..new batteries defective can do this type of issue like you have where on one moment it starts normal then another time not..


after the these are checked out then it can be bad/loose connections at starter or the solenoid on starter..being a 1996 the starter may indeed be in need of replacement..

sometimes a starter can open like worn brushes or worn solenoid contacts..some the bushing is worn causing the starter to bind up on the flywheel ..

the alternator output voltage varies on temperature...on cold start the voltage at 50 deg f will be about 14.75 volts DC..when the engine is at operating temp and the air temp is 50 deg f the voltage should drop to 13.25-13.75 volts /////in a hotter area like AZ 115deg f it will be in the low 13 volt range...below zero f it will be 15 volts..

a weak battery will charge very fast as the cells are damaged..

8 amps is quite high on charge from a charger...meaning the battery was drained somewhat..

with the engine off turn on your headlamps and see how long the volts stays above 12 volts..if not long it would be in the battery or charging ..

[jsgold]

I charged it last night for six hours and this morning removed, cleaned and installed the cables on the battery. The charge rate was a pretty constant 3 amps. It went up to 7-8 for a few seconds, then dropped. Now the battery (after sitting several hours) registers 12.69 volts and charging shows 14.65 +- on my digital meter. I had noticed for some time that my dash guage was showing 2 marks below the 14 amp mark and I was curious that perhaps the alternator was getting old. Now it is back above the 14 amp mark on the dash and all seems well. My suspect is the cables although I won't rule anything out right now. I remember that when I first got this truck the darn thing stalled out on me on my way home and everything went dead. I checked and the cable and found it was not fully tightened. Started right up and about a month later it did it again. The cabel was not dirty, and still looks clean although I did hit it with the brush a little. You really have to torque it down so maybe the cable is not making the best contact....Of course with 238,000 miles and a 96' model that would be no surprise. I will keep tabs on it and let you know further.

[j cAT]

Originally Posted by jsgold

I charged it last night for six hours and this morning removed, cleaned and installed the cables on the battery. The charge rate was a pretty constant 3 amps. It went up to 7-8 for a few seconds, then dropped. Now the battery (after sitting several hours) registers 12.69 volts and charging shows 14.65 +- on my digital meter. I had noticed for some time that my dash guage was showing 2 marks below the 14 amp mark and I was curious that perhaps the alternator was getting old. Now it is back above the 14 amp mark on the dash and all seems well. My suspect is the cables although I won't rule anything out right now. I remember that when I first got this truck the darn thing stalled out on me on my way home and everything went dead. I checked and the cable and found it was not fully tightened. Started right up and about a month later it did it again. The cabel was not dirty, and still looks clean although I did hit it with the brush a little. You really have to torque it down so maybe the cable is not making the best contact....Of course with 238,000 miles and a 96' model that would be no surprise. I will keep tabs on it and let you know further.

you need to get the battery load tested.. this is how to determine if it is defective . If it is weak this should be replaced for free since it is not that old.

the voltage to the battery from alternator if between 13.75 and 14.75 volts with the weather as it is now in your stated area is quite normal..measure this when cold also when engine hot..it should be in this range..do not use the dash volt guage as being accurate..

grounds as well as the positive connections ALL must be cleaned and secured..looks don't help ....

cleaning connections is required whether this has 30,ooomi or 300,ooomiles..same thing will happen !

make sure the battery is mounted secure ,,,,,,,,,,,,,,,,,,,,,,,,,,,not flopping around...

[jsgold]

Yes, the battery will be tested in the next day or two. I have an Advance auto store pretty close and have to get a battery for my 2004 Blazer anyway so I will take care of both. The blazer's battery lasted for 7 years...time for a new one(2.97 volts left...dead. LOL)
I generally clean cables once a year on the battery end. Probably need to check the other ends too. Dash guage reading was only important to me as I noticed it back to the original level as before. I will take some other readings and get the battery tested and get back in a couple of days. If everything tests out OK I will pull the cables and either clean further or replace. I use this old truck to pull my boat and camper, and it normally does not get driven more than once a week at the most. I have had to drive it more as of late though. Regardless, don't want to have to deal with a dead battery 40-50 miles from home.

[j cAT]

Originally Posted by jsgold

Yes, the battery will be tested in the next day or two. I have an Advance auto store pretty close and have to get a battery for my 2004 Blazer anyway so I will take care of both. The blazer's battery lasted for 7 years...time for a new one(2.97 volts left...dead. LOL)
I generally clean cables once a year on the battery end. Probably need to check the other ends too. Dash guage reading was only important to me as I noticed it back to the original level as before. I will take some other readings and get the battery tested and get back in a couple of days. If everything tests out OK I will pull the cables and either clean further or replace. I use this old truck to pull my boat and camper, and it normally does not get driven more than once a week at the most. I have had to drive it more as of late though. Regardless, don't want to have to deal with a dead battery 40-50 miles from home.

with batteries volts and amps output is required when testing..

I have had intermitent opens and shorts with batteries...they can be tricky..the load tester with the battery fully charged is the only sure way to know if its good..

post back how the battery tested and if bad what manufacturer..my batteries are getting at 7 yrs now so I am going to buy one soon.

good luck !

[4x4junkie]

wouldnt hurt to check the ground connection between the motor and frame, as well as frame to battery, we all know how ground lugs tend to cause several issues on these vehicles........ and lower voltage reading woould be affected more by a bad round connection when starting.