need some cummins help

[WilltheThrill]

I know its no IDI but you guys have helped me out so well in the past.
So my dads 126000mi 06 dodge is giving him some trouble. Driving down the road volt gauge seems to drop and the truck acts like its going to die the check engine lights comes on. Then the truck jumps back to life and goes back to running like normal? we just changed the fuel filter, and still same problem??? after a couple days the engine light goes off and all is good.
Due to the voltage drop he thinks the serpentine belt has stretched and is not right, any ideas?

 

[dsltech83]

What codes does it have in it- that would be the best place to start if the Check Engine Lamp is on.

 

[benton]

it might be the alternator dieing! and i dont think its the serpintine belt because the have spring adjust idle tesioner if im not mistaken!

 

[itsacrazyasian]

I know its no IDI but you guys have helped me out so well in the past.
So my dads 126000mi 06 dodge is giving him some trouble. Driving down the road volt gauge seems to drop and the truck acts like its going to die the check engine lights comes on. Then the truck jumps back to life and goes back to running like normal? we just changed the fuel filter, and still same problem??? after a couple days the engine light goes off and all is good.
Due to the voltage drop he thinks the serpentine belt has stretched and is not right, any ideas?

Did you scan the CEL?

 

[BigRigTech]

You need to check the codes, also check for good clean power and ground to the ECM....The voltmeter going nuts sounds like it could be a poor ground to me.

 

[WilltheThrill]

I will see pops and the truck tuesday, I will be pulling codes and looking into grounds...any other ideas?

 

[jperecko]

is it only when cold? cummins have intake grid heaters which take power like crazy so if it is dropping voltage when cold... it is just the grid kicking on

they tend to cycle a bit

 

[itsacrazyasian]

Well without codes we're shooting in the dark. I will tell you this though if you get a p2509, check the batteries and the heavy battery cables well. And when i say check the batteries i mean load test them. I've had a bunch of trucks with surging idle or random stalling due to bad batteries. They usually had a p2509 stored though. One truck had a bad ECM but it was a tow truck and i think the owner tried fiddling with it himself and burned the ecm up.