Slow cranking but starts

[Roadboy]

First off, new last year-battery, alt(running puts out 14+v), starter and ground strap from batt. I get in and hit the key and it acts like it's got a really weak battery, slow crank and clicking. let it click/crank for about 10 sec and it will start. Check the voltage at the battery before and it's at 12+. Check with the key on and it drops to 10. I checked the voltage at the starter and its getting 12+(key off), but at the little studs on the starter (both) while cranking its getting like 5volts. When it finally starts it runs rough and wants to die, so I feather the gas for a min and she cleans up her act. This combination of things is what has me puzzled. I'm getting the starter checked later today and the only other thing I can think of is the ignition switch wiring in the steering column which appears to be quite pricey. I also ran a batt cable from the batt + to the starter and then switched it to the ground side and still no help so the cables seem good. Thanks for any help

 

[iamdub]

Try jumping it off another running car before you try to start it. Even though the battery is relatively new doesn't mean it's not faulty. The voltage is ok at rest, but it may not be able to push the amps under load such as when starting. This drags down the voltage which starves everything for power, including the fuel pump. The fuel pressure is weak at start-up, so it doesn't want to idle. Once it's running, the alternator revives everything with it's 14+ volts, and the fuel pressure jumps up to where it needs to be and all is well.

 

[sumo]

Check battery cables and grounds. Sounds like you may have unwanted resistance/corrosion.

 

[Roadboy]

It fires right up if I jump it off another car. Sumo: I replaced the ground to batt and swapped in a new positive for a min. Thanks guys I'm gonna go check the amps now

 

[dubyagee01]

Do a voltage drop test

http://www.aa1car.com/library/voltage_drop_testing.htm

 

[Roadboy]

Voltage at the battery while starting is at 6-7 volts, looks like I'm going to trade in my year old battery tomorrow. Thank you everybody

 

[sumo]

Have you had your battery tested? Bad cell?

 

[Roadboy]

Sumo, I plan on taking it in this afternoon. I brought it to work and am charging it now

 

[iamdub]

It fires right up if I jump it off another car. Sumo: I replaced the ground to batt and swapped in a new positive for a min. Thanks guys I'm gonna go check the amps now

Yup- bad battery. It may hold 12 volts at rest but it clearly can't hold that voltage under load. Hopefully it has a warranty. Duralast?

 

[ISU-152]

Ya one year on a battery is no good....hope you keep receipts