isx cm2250 enigne brake

[hct5]

alright so the truck is shutting down with a fault code 3253, but all the testes pass. it says in the possible causes that Excessive engine oil or diesel fuel being introduced into the exhaust system from the engine could be the issue. the driver stated that it only dose it when the engine brake is on. pulled the valve cover and i found 2 engine brakes that when pushed down onto the valve they do not spring back. could this be the issue ? they are sticking down keeping the valve open and letting excessive fuel into the exhaust system?

[Rawze]

Fault code 3253 = DPF Inlet Temp sensor is Above its Normal Range.

this can happen if it is in a regen and it goes too high .... OR ... If it is not in a regen and the DPF inlet temp sensor reads higher than the normal exhaust temperatures.

* Could be one or more of ...

* Bad, mis-reading DPF inlet temp sensor or wiring for it.

* The engine is letting oil build up on the face of the DPF and igniting due to excessive blo-by or leaky exhaust turbine on turbo.

* You have a leaky Doser injector.

* Bad Valve guide seals that are quite bad, allowing oil into the exhaust.

* Leaky injector, allowing fuel to get into the exhaust via the exhaust stroke(s) of the engine.

======================


* Will it pass an injector leak test?


* Anyone pulled the Doser pipe away from the turbo, cranked the engine up, and looked to see if it is seeping fuel from its nozzle?

* Anyone pulled the intake and exhaust piping off the turbo to see if turbo is leaky?

* Anyone replaced the DPF inlet temp sensor to ensure it is not reading incorrectly?

* Does it have an aftermarket DOC or DPF unit on it? .. If so, this could be the issue.

* Anyone pulled the DOC and DPF, taken detailed pictures of their faces, and looked to see what kind of buildup is on the face of each?

* Anyone checked to see if the decomp tube does not have the dreaded "Volcano" in it, partially blocking off the exhaust system? ref: http://rawze.com/forums/showthread.php?t...07#pid1807


* Any mysterious coolant losses?

* Anyone removed the turbo + exhaust manifold off after a 20-second quick cold-start, then shut down to see if any of the the exhaust valves (or inside of manifold) at one or more cylinders are wet with oil or fuel?


just some thoughts.

[hct5]

we have checked almost all of this, this is the engine that was rebuilt by another shop. they had messed up installing one of the piston sleeves and it was leaking coolant into the oil. the head and injectors where tested when it was rebuilt maybe 1000 miles ago. not leaking turbo or doser, the decomp tube looks good. i just changed the temp sensor and try to do a DESA test and it stop saying the DOC outlet temp exceeded 1112 def. the dpf and doc are fairly new OEM. wondering if i should pull the doc and see what it looks like.

[hct5]

looks like the bottom of the DOC has some build up on it. i would say it covers a 1/4 of the DOC face.

[Rawze]

(03-04-2021 )hct5 Wrote:  we have checked almost all of this, this is the engine that was rebuilt by another shop. they had messed up installing one of the piston sleeves and it was leaking coolant into the oil. the head and injectors where tested when it was rebuilt maybe 1000 miles ago. not leaking turbo or doser, the decomp tube looks good. i just changed the temp sensor and try to do a DESA test and it stop saying the DOC outlet temp exceeded 1112 def. the dpf and doc are fairly new OEM. wondering if i should pull the doc and see what it looks like.

sounds to me like this engine might be doomed to fail again from what you describe on how it was inframed.

[Rawze]

(03-04-2021 )hct5 Wrote:  looks like the bottom of the DOC has some build up on it. i would say it covers a 1/4 of the DOC face.

need to tear it apart and see what this is exactly.

[tree98]

Maybe this thing sat in a flood somewhere?? Why else would just the bottom 30% of the DOC look like that.