Aftertreatment isx 871 part 5 DOC Doser injector

A comprehensive overview of the aftertreatment DOC doser injector.
We talk about flows and show mounting kit parts. When you buy the injector you can buy it as a kit with the mounting gaskets.

[@KCsAsphaltHustle]

I have a paccar mx13 epa 17 and I changed my doc and dpf all the sensors. The turbo actuator. And the egr valve. And for some reason my doc is overheating during regen. Could my fuel dossier cause this. Thanks in advance

[@ENGINESHOPJOE]

We have about a dozen of these engines in our fleet. We have had a lot of injector problems. There is a special flush and I think software update that has to be done. Paccar dealers have been fixing ours. I am not that familiar but if this has a seperate fuel doser injector it could be causing this yes.

[@KCsAsphaltHustle]

@@ENGINESHOPJOE thank you

[@Yotubefamilia____1]

I took mine off and went to freightliner and they didnt have it , So I got one from peterbilt . Do you thing thats a problem? I Dont think i got the correct part

[@ENGINESHOPJOE]

If it's the correct part number and it bolts up its ok. It should look very similar but they did make a few physical changes but nothing that would make on say - there is no way this is it. If you are worried call 1*800-cummins with your engine number and ask them the part number. If it is different give them the part number and ask them if it is correct. When you buy parts from dealers sometimes they put their part system number on it not cummins (in this case) So its ok if the box has a different number. Cummins put the part number on all parts so look for the 7 digit numeral and that should be it.

[@Yotubefamilia____1]

Thank you 🙏🏽🙏🏽🙏🏽

[@MarkZepeda-pb7pf]

My doser injector is the same on my peterbilt 579 just got a code spn3556 after treatment fuel injector 1 FMI 5 current Below Norma or open circuit. Code came on after having to charge batteries because it wouldn't crank over after LVD warning came up on dash. Any guidance could help. I would be checking the wires to harness to ACM module or could it be doser itself that's no good. And whats that blue zip tie on doser for? Anything would help thanks

[@ENGINESHOPJOE]

The zip tie clamps the pigtail to a flange on the injector so it does not break off from normal daily vibration. Dont remove it. The injector has a coil in it but it is pulse width controlled not a traditional DC circuit. At key on the ecm pulses the injector and expects to see current return. The engine ecm drives that injector. If the batteries were low that could of caused improper check verification. I would charge the batteries or get the unit running. Then do a 2 minute key off. You may have to put the unit into a stationary regen before it will verify the injector is OK. try to reset the fault even if it is active. If the injector ohms out in range and none of the proceeding worked i would recalibrate the engine ecm. It is very rare but if battery voltage is very low the ecm might of locked the fault in the fault ecm ( there is a seperate bus and ecm for fault logging). A software recal completely rewrites the controls so all the faults are erased. If they come back after a cal and the injector checked out look at the harness or a connector for that circuit. I doubt the ecm is failed or damaged- very rare.

[@realmccoy9597]

I replaced mine and it keeps dumping fuel into the exhaust system causing crazy amounts of smoke, what would cause this?

[@ENGINESHOPJOE]

If you have an ISX-871 the injector gets fuel from a housing bolted on the cylinder block drivers side. When the injector is not being used no fuel should be in that block. There is a drain valve and supply valve along with a pressure sensor in the housing. I suspect the supply valve is leaking and allowing fuel to pressurize the housing while you're driving the ECM pressurize the housing at start up and then dumps the fuel out of it. This is a self test. It then opens the injector behind the turbo. If, for some reason, there is fuel pressure in that housing. It will fill the exhaust pipe with fuel. However, you won't see the white smoke until the exhaust system gets hot enough to start to burn it. Unbold injector leave the lines on start the engine, while someone watches to see if fuel is spraying out of the injector at start up. Rarely, I have seen the housing I spoke of earlier, fail internally and always send fuel to that injector.

[@realmccoy9597]

@@ENGINESHOPJOE I've replaced the fuel valve and injector and it still continues to inject fuel into the exhaust! I reset the aftertreatment system and it went away for about 5k miles and it came back again, I reset it again and and we'll see what happens. Cm2350

[@realmccoy9597]

@@ENGINESHOPJOE I appreciate your channel and response buddy.

[@ENGINESHOPJOE]

@@realmccoy9597 The 2350 is a little different than the 871. It has an air solenoid the ecm turns on once injection is completed. That air solenoid pressurizes that injector with air to blow all the fuel out of it and the line feeding it. That is to help stop carbonization of the tip which leads to poor atomization. If the problem continues let me know and I will see what I can find on what could be causing it.

[@ENGINESHOPJOE]

@@realmccoy9597 Thanks for the kind words.