Replaced battery now truck doesn't run right

[sam hain]

Last week I went to start my truck and it just clicked, checked voltage on the battery and was 10.

Removed battery and replaced it with a brand new one.

Ever since my truck has a very low idle and has mis-fire codes stored P0172 and P0175, CEL is not on though.

Idle is around 3-400rpms and has a noticeable mis/skip in it. Transmission also shifts hard up/down.

I've checked the battery with the truck running and it shows 15v being put to it at idle so I know the alternator is working. 

Once driving it seems to run fine, normal power etc. The problem seems to be at idle.

I've removed the battery cables twice now and let the computer drain again, then hooked everything back up.

Someone on the facebook group said to let it idle for 5mins and it should "learn" again and reset the idle. I've done that and it didn't help anything.

I've got a shop nearby I thought about seeing if he could hook up his scan tool and see if it shows something my little cheap code reader doesn't.

Just to note, the truck ran fine before the battery issue. It was the stock battery (4yrs old) so I assumed it died because of age.

[sam hain]

Update:

 

Found out you have to do a battery reset to the computer, having it done tomorrow will report back.

[carnau]

2 hours ago, sam hain said:

Update:

 

Found out you have to do a battery reset to the computer, having it done tomorrow will report back.

Ok, Is someone going to charge you for this? There is no such thing as a battery reset for the computer. Trust me, I know. I have put in 1000 batteries in these trucks and never ever have had to do this. I also work at a GM dealership with a mass of other techs who also replace these batteries never having to do this.

 

Let's start by doing this. Who installed the battery? 9 times out of 10 if someone else installs your battery other than a tech you will have this issue.

On top of the battery itself is a Battery block. A lot of times things either get left loose here or the metal bracket gets cracked during removal. This is a very thin piece of metal that transfer the power. Below is a picture of the Battery Block. The next picture has colors on it and I want you to check this the way I explain.

 

First, The green circles on the image. I want you to gently wiggle these wires and see is they are loose. Also take an 8mm Socket and tighten them up just to make sure they are tight. A lot of times these will be left loose and are not seated correctly. Make sure they are in the right order too. You will see numbers on them. Number 1 cable should go to number 1 on the block ect.

 

After all these have been checked and made sure they were tightened correctly. Goto this step if you have not found the problem.

 

Take a test light (a cheap test light with a cheap bulb is the best. So don't spend a lot of money if you don't have one. Buy the least expensive one that's NOT an LED test light. You do not want an LED) and test all the red spots on the picture to the ground. So connect one side of the test light to the ground post and touch the red spots with the other and make sure they all light the test light up FULLY. If one is not as bright as the others, make sure to let me know. They should all light the test light up bright.

 

Let me know what you find when you have checked this.

[sam hain]

Thanks for the help Chris, I will check these and let you know.

[sam hain]

My setup doesn't look exactly like the picture you posted. I don't have a check light I'll have to go get one, but all the connections were tight. I noticed I didn't have a wire on #3 I looked everywhere and didn't see a loose wire. 

 

[midwestdenaliguy]

For what it's worth, my battery just died in my 2016 Sierra Denali and I replaced it myself. Zero issues and no 'battery reset'. Never heard of that.

[sam hain]

I found a test light, everywhere I put it I the light lit up.  I started the truck after checking everything (cold start) and it started normal, idled up to about about 1200rmps for about 30sec then dropped down to about 400rpms and started missing. IDK know what's going on, the truck ran completely normal before the battery died.

[Snowcamo]

Sam. Did you have a shop install your battery? Did you/ they notice a spark when the wrench touched the body of the truck? What else could have gone wrong?

Sent from my LM-G820 using Tapatalk

[evad]

maybe check plug wires and other connections in area of battery .....might of got messed up when taking out bat ..??? sometimes its the stupid things

[sam hain]

16 hours ago, Snowcamo said:

Sam. Did you have a shop install your battery? Did you/ they notice a spark when the wrench touched the body of the truck? What else could have gone wrong?

Sent from my LM-G820 using Tapatalk
 

My FIL removed the battery for me since I'm working from home because of COVID, I put the new battery in. No sparks or anything like that. Just very strange how the problem seems to only be with the idle. Once driving you would never know anything was going on.

[sam hain]

14 hours ago, evad said:

maybe check plug wires and other connections in area of battery .....might of got messed up when taking out bat ..??? sometimes its the stupid things

I've looked over the battery area no less than 10 times now and can't find anything obvious. At this point I may need another set of eyes to look it over because I'm not finding anything.

[sam hain]

Buddy of mine has a matco scan tool, problem (oddly enough) is the Mass air flow sensor. His scan tool showed one code for it, plus he has a 2015 Silverado and we swapped out his mass air flow sensor and my idle returned to normal. 

[midwestdenaliguy]

2 hours ago, sam hain said:

Buddy of mine has a matco scan tool, problem (oddly enough) is the Mass air flow sensor. His scan tool showed one code for it, plus he has a 2015 Silverado and we swapped out his mass air flow sensor and my idle returned to normal. 

Glad you found the issue. Sucks when a different issue pops up right when you fix one and it really throws you. Got it resolved quickly though!