HEST light on too often...

[Rawze]

(06-25-2016 )Brock Wrote:  A local mechanic said there is a differential pressure sensor on thr side of the dpf and he has seen those cause similar constant regen issues.

That is correct. Poor quality regens sometimes are caused by ...

* Dirty IMAP and/or Exhaust back pressure sensors.

* Clogged Venturi and other EGR piping.

* the Delta-P for the EGR (bad sensor, leaky joints, and/or clogged tubes going to it)

* The egr valve sticky

* leaky EGR cooler, or excess oil consumption/blow-by

* leaky injectors, creating poor combustion.

* High crank case pressure due to clogged crank case filter or excess ring wear.

* Turbocharger out of calibration or not positioning properly due to excess wear.

* A bad and/or leaky exhaust manifold gasket or turbo gasket.

* A leak in the EGR piping where it goes around the back of the engine, or at one of the other joints.

* Worn out, or clogged tip on the Doser Injector.

* A CAC leak that is causing lower than normal fuel mileage, or an after-market CAC unit (like Duralite etc.) that is slightly restrictive.

* An exhaust leak between the back of the turbo and the front of the DOC/DPF. Even a slight leak can have a serious impact on how well it regens.

* the Delta-P for the DPF not reading correctly (bad sensor, leaky joints, and/or clogged tubes going to it)

* The DPF or DOC clogged and/or face pluged by ash, coolant or oil buildup.

* The DOC can be simply worn out and have little to no chemicals in it due to either age, or the fact that too much oil, coolant, or even unburnt fuel from regening too often washing it out.

* A cracked DOC or DPF

* A slipped injector or valve cam

* A very dirty air filter

* bad driving habits where you are taking it out of gear/coasting too often (this cancels the regen cycles).

* Using a lot of PTO and/or idling it for several hours at a time.

* Having the wrong program in the ECM for that style of truck and/or DPF. Many people change the HP rating for engines incorrectly.