Peterbilt 386 starts and dies immediately

[shawn21998]

Hello everyone new user here long time lurker hoping y'all can help me out with this one. I have a 2013 Peterbilt 386 with a ISX15 CM2250. Truck will start right up and die immediately. Only active code is SPN 168 FMI 1 "SAE-Battery potential (voltage) data valid but below normal operating range - Most severe level" from component 128. And "Power supply ignition voltage too low" (spn 627 fmi 4) from EC-60ABS. Batteries are new and code still comes up with charger connected. I have cleaned battery and starter connections and checked grounds. Performed voltage drop on grounds at engine and chassis with around 1v drop during cranking. All fuses and relays seem good. Lowest voltage while cranking is 10.7v at batteries and 7.2 at starter. Hoping to get a diagram for OEM connector at ECM so I can test voltage at ecm. I have jpro and use cummins quickserve but the battery code is OEM and quickserve has no information for that code. Any help is greatly appreciated.

[DVT873]

Pull the pipe between the turbo and the charge air cooler (CAC) or the charge air cooler and the intake. If the turbo is seized engine can't get enough air to stay running.
If it still won't stay running drop an exhaust pipe between the cans and the turbo although blocked exhausts usually won't fire at all.

[shawn21998]

I forgot to mention I have already pulled the EGR crossover pipe to allow the exhaust gases to escape in case the VGT was stuck

[Bengy88]

Have you checked/replaced your fuses and checked for corrosion in your fuse panels/pdm?
I’ve seen a shi#t ton of paccar products give this exact issue or a no start at all caused by corrosion in fuses and inside the pdm’s…… just a thought.

[shawn21998]

(10-24-2023 )Bengy88 Wrote:  Have you checked/replaced your fuses and checked for corrosion in your fuse panels/pdm?
I’ve seen a shi#t ton of paccar products give this exact issue or a no start at all caused by corrosion in fuses and inside the pdm’s…… just a thought.

Yes I have checked all fuses in panel on firewall and kick panel along with relay center behind cluster. I have visually checked wiring underneath drivers side cab mount where they typically corrode, all checks out.

[Bengy88]

Do you have any diagnostic software to monitor voltages and ecms during this? I may have an oem harness diagram I’ll look over the night

[shawn21998]

[quote='Bengy88' pid='78456' dateline='1698200073']
Do you have any diagnostic software to monitor voltages and ecms during this? I may have an oem harness diagram I’ll look over the night
[/quote

Yes all I have is jpro but it doesn't show real time ECM voltages that I know of. That's why I was trying to figure out what pin is battery power for ECM at OEM connector. ECM is due for calibration update as well but I don't think that would cause this issue. Unfortunately I don't have access to cummins insite anymore.

[Bengy88]

I just pm’d you my number. I can send you a schematic and if you want I’ll remote in and monitor a few things and give my opinion if you want

[Rawze]

cranking up and then stumbling out sounds more like a fuel issue to me... but one never knows when they are just guessing at it on a forum...

fuel pump acting up or going out?. - Has anyone bothered to pull the fuel pump head off and inspected the plungers, rollers, cam, etc?.



Performed a plunger test to ensure they are not sinking ... and Also pulled them put and flipped them upside down to see if they go into the holes upside down, to ensure they are not not flared out slightly at the tops, causing sticking when operating?.