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biggins2001 · 04-10-2018, **(Subject: Cummins isx regen issues. )**

Good morning and thank you for adding me to the forum. I have a 2010 peterbilt 386 with an cm871 cummins that I'm having some regen issues with. The original code that the truck came in with was a 1691 aft doc conversion efficiency. Through diagnosis we replaced the doser, and removed the doc to find the doc face plugged, this truck has had multiple injector issues which I think we have finally gotten those under control. We cleaned the doc and inspected for proper light transmission which it passed, the dpf filter was cleaned 10k miles ago. After cleaning the doc it was reinstalled on the truck, reset doc/dpf counters. Performed manual stationary regen, the truck kicks up to 1200-1300 to start regen, the turbo speed starts at around 42k and turbo actuator 92%, egr valve position consistently stays at 0%, exhaust gas pressure about 140, intake manifold pressure about 12.5. Once the doc intake temperature reaches 525-540 the turbo actuator drops back between 90-91% turbo speed raises to 47-52k, intake manifold pressure raises to 18-20, and exhaust gas pressure raises to between 160-165. When all of this happens the doc intake temperature drops off to 460. When the doc intake temperature gets to around 460 the turbo actuator will then close back to 91-92%, temperature will build back up to about 540 then drop off again. All this time never getting to the point of dosing. It will continue to do this for up to 2 hours if you will let it before throwing conversion efficiency again.

Before changing the doser and cleaning the face plugged doc the intake temperature would range from 560 to 630, which again will not allow the system to get hot enough to complete a regen.

Any help would be greatly appreciated.

Brett

RTRUCKING48 · 04-10-2018, **(Subject: Cummins isx regen issues. )**

(04-10-2018 )biggins2001 Wrote: Good morning and thank you for adding me to the forum. I have a 2010 peterbilt 386 with an cm871 cummins that I'm having some regen issues with. The original code that the truck came in with was a 1691 aft doc conversion efficiency. Through diagnosis we replaced the doser, and removed the doc to find the doc face plugged, this truck has had multiple injector issues which I think we have finally gotten those under control. We cleaned the doc and inspected for proper light transmission which it passed, the dpf filter was cleaned 10k miles ago. After cleaning the doc it was reinstalled on the truck, reset doc/dpf counters. Performed manual stationary regen, the truck kicks up to 1200-1300 to start regen, the turbo speed starts at around 42k and turbo actuator 92%, egr valve position consistently stays at 0%, exhaust gas pressure about 140, intake manifold pressure about 12.5. Once the doc intake temperature reaches 525-540 the turbo actuator drops back between 90-91% turbo speed raises to 47-52k, intake manifold pressure raises to 18-20, and exhaust gas pressure raises to between 160-165. When all of this happens the doc intake temperature drops off to 460. When the doc intake temperature gets to around 460 the turbo actuator will then close back to 91-92%, temperature will build back up to about 540 then drop off again. All this time never getting to the point of dosing. It will continue to do this for up to 2 hours if you will let it before throwing conversion efficiency again.

Before changing the doser and cleaning the face plugged doc the intake temperature would range from 560 to 630, which again will not allow the system to get hot enough to complete a regen.

Any help would be greatly appreciated.

Brett

Did you ever perform the egr tune up?

Rawze · 04-10-2018, **(Subject: Cummins isx regen issues. )**

Also check to ensure you have the right program in the ECM for the build. that can do things like that too.

biggins2001 · 04-11-2018, **(Subject: Cummins isx regen issues. )**

egr tune up and new egr cooler was completed on this truck about 65,000 miles ago when engine was rebuilt. I am in the process of going through the entire egr system and cleaning the system again now.

RTRUCKING48 · 04-11-2018, **(Subject: Cummins isx regen issues. )**

How's the regen history look like?

biggins2001 · 04-12-2018, **(Subject: Cummins isx regen issues. )**

While cleaning the egr system we found that the barometric pressure sensor was mostly plugged. Cleaned the sensor and installed a new delta pressure sensor just because there really isn't a good way to clean the sensor and know that its clean when you re install it. After cleaning the egr valve and all the sensors the temperatures ramped up like they should and completed a proper regen.

Thanks for the help guys.

RTRUCKING48 · 04-12-2018, **(Subject: Cummins isx regen issues. )**

(04-12-2018 )biggins2001 Wrote: While cleaning the egr system we found that the barometric pressure sensor was mostly plugged. Cleaned the sensor and installed a new delta pressure sensor just because there really isn't a good way to clean the sensor and know that its clean when you re install it. After cleaning the egr valve and all the sensors the temperatures ramped up like they should and completed a proper regen.

Thanks for the help guys.

Good deal glad you found the problem