Hi. Sorry if this post is in the wrong spot. This is my first post.

Last week my truck died and wouldn't start on a jump. An auto-place tested the battery and alternator and said they were both bad, so I replaced them.

The battery gauge drops every time when we are driving and stop and it seems like it wants to die. I'm afraid to turn the wife and kids loose in it now, because I'm not sure if it is going to go deaD again.

I measured the battery voltage on the battery at idle 14.2V steady. In the morning when checking the battery it reads 12.6V with truck engine off.

It's weird because if the truck hasn't been moving and I push the brake idling in neutral, the batt gauge is stable. Only when I'm driving down the road and slow down the battery voltage drops.

I'm wondering if this drop at stops could be enough to kill the battery eventually and maybe the issue is more an engine RPM thing.

I have NO engine code displayed. I tried cleaning my batt temp sensor under the tray thinking it might be a weak connection on that, but it didn't help. I did disconnect the batt temp sensor to see what the PCM would do and it gave me a P1507, so it seems like if the batt sensor was an issue the computer would log a code?

Anyone seen this? I just don't know if the engine idle is causing the battery drop or if the battery voltage fluctuations is making the truck want to die.

Battery hasn't went dead yet, but I have not driven it much until I can tell if there's a problem.

I just drove the truck to autozone and they load tested it and battery/alternator checks ok for now anyway. Still wants to die at stops and voltmeter still drops.

Thanks for taking the time to read this.

 

what year? Engine size? Auto Tranns? Idle RPM? Miles on the truck? Need more info to help.

 

Welcome to the forum. We need the info mentioned above to give proper replies. Sounds like the idle is dropping to low when stopping causing the voltage to drop, and want to die.

 

I agree with Lxman, the altenator requires a minimum rpm to produce enough voltage and amperage to charge the battery/supply correct voltage to run the truck.

More info please

 

it could also be a bad ground or grounds. check them. clean them.

 

Hey thanks, Its a 2005 quad cab Dodge Ram hemi 6 cylinder with a manual 5 speed transmission. I did clean all battery terminals and grounds (forgot to mention that in my first post. Still it's always possible I missed something). It has 75,000 miles on it.

The RPM: Started cold in neutral it idled approx 900 RPM. Drove around the block a few times (afraid to get too far away) and when stopping it drops to 300-400RPM and idles real rough for approx. 2-4 seconds then pops back up to around 700 RPM.

I tried shifting into neutral as I was stopping to see if the tranny being engaged was influencing it, but it behaved the same.

I appreciate the help. I'm thinking about cleaning the IAC, but I'm not sure where it is. There are 2 sensors on my throttle body one right over the other. I'm not sure which one is the TPS or the IAC? I may be completely on the wrong track with the IAC though?

 

If you have an EGR Valve I would change that to as it is known for rough idle problems like you describe.

 

Ok. It's fixed except for the thing I broke in the process. I totally disassembled the throttle body and removed the TPS and IAC. Sprayed the whole throttle body with electric motor cleaner. It had a bunch of gunk in it. The IAC was really filthy as well. Now she idles at 600-700 RPM steady and smooth.

The darn IAC connector was siezed on the IAC and I broke off the locking tab fighting with it.

Not sure how to replace that, but I am going to try a metal wire tie. I dont think a nylon zip tie would hold for long with all of the heat.

It's a curse. I always break at least one thing in the process of trying to repair stuff. Dang.

I hope this helps someone else having this issue. It was kind of a PITA. Took most of the morning, but I've never disassembled those components before. The hardest part for me was removing the IAC connector and figuring out I needed a size 20 torque bit for the sensors on the throttle body.

Anyone know how to repair or replace the broken IAC connector? (engine harness side)

I also sprayed the connectors with contact cleaner while I had them off.

 

Get a connector at the wreckers and splice it in. Those little red tabs can be a learning experience.

 

thanks for the follow up, i just picked up a 2003 1500 with 180k miles, it runs great, but knowing my dad he never cleaned the intake assem. i might pull it off and clean it now to prevent future problems.