Emissions Faults (Technical) - Pls Advise

[Quantum]

It's a whole big operation for me to run ET as I have to replace the disk in my laptop since I normally run Linux.

After this latest test it looks like I'm punked, skunked, and defunct. No clear answer.

Have the whole system back together, removed the injector and put it in a baggie, and started the engine 3 times, each run being about 2 minutes. All that was in the baggie is the first picture. That doesn't look like I think it should be after 3 starts, although it does smell like DEF.

Second picture is ET SCR 1. Terrible pressure. Its behavior is clear: the pump runs forward for 1.5 minutes, then stops and reverses. There seems to be enough volume and pressure when forward.

So if the pressure reader is wrong, there is not enough fluid in the baggie because it's just circulated at first? It would make sense for them to do that. It doesn't seem possible to order just the pressure transducer as I believe it's in the pump assy at the outlet, which is $2,500. Can I hotwire the transducer if it's bad? If it's just a switch, surely so.

Pulling a vacuum. I have a shop-vac. I've run over the DEF cap (left it on the track) and that's $75, so I have only a baggie stuffed in there for now. I do have an HVAC vacuum pump, so maybe I could rig up a cover with schrader fitting and put my pump/gauges on it. I'm 90% sure my system is closed, but it may be worth testing.

This is the sum of what I know after carefully going through every stage of the system in detail. It's good to have confirmed that DFP regen is inhibited because of this, although now I'm at Stage 2 of a plugged-up DPF. Not long before Stage 3 and I have to disassemble the whole top of the machine to remove and try to clean the DPF. (although back-pressure is zero)

 

[BigWrench55]

Bypassing the pressure transducers will not get you anywhere. The ecm needs to see the pressure it wants or it will trip a code. Another thing is if you don't have dealership level ET you will not be able to reset the ash and soot levels after doing a forced regen. There should be a test in et that will allow you test fire the doser what you call the injector. Cat didn't design the system and I am certain that it is a licensed Version of what Cummins designed. You may want to try Cummins for a new def pump.

 

[Quantum]

Well that's not good news. But I'm going to test the transducer to see if it's just a switch and probably bypass it anyway. I do have ET 2017 Factory, but I don't find where to reset ash and soot levels, although I am an amateur.

I've gone through the schematics (attached) and all they give is a square block for the DEF pump box. But there are wires for the pressure sensor coming out of it so I'm confident that the device on the output line is a pressure transducer. Nothing else could be it, just heater and pump wiring.

The 3.8 liter engine is Kubota, and I've searched extensively for an in-line DEF pressure sensor with no luck. Maybe when I open up the DEF pump there will be a manufacturer somewhere.

I have tried Kubota for an injector after I found the part number on it, and Kubota charges more than Cat! ($1,200)

 

[Quantum]

So the pressure transducer is absolutely inside the DEF pump box, and it is a transducer not a switch because {der} it reports the DEF pressure.

It is the device on the output line, and I've broken it down to the part shown. I put a probe into the port to test if it's a switch, and may have damaged the delicate aluminum membrane.

I didn't think to look for plugging of its ingress port, as I'm so panicked about this, which may well could have been the problem. (before I probably broke the sensor) It has 3 wires, which may mean it's a potentiometer.

It has cast into the plastic the brand Epcos (which is a TDK company), and laser-engraved are the (faint) numbers:
BL10 11 4026786
BS8621M3200B021

Epcos does in fact make pressure transducers, although G**gle is baffled by either number. I can't find any Epcos pressure transducer or sender in this formfactor.

 

[Birken Vogt]

I have had numerous cases of small electronic parts like this that are only reasonably available through Cat or similar. Even though the manufacturer may sell other products from their line to the general public.

 

[Quantum]

Sure, but unfortunately Cat's SIS only lists the whole DEF pump box as a FRU. There is no part# for any parts internal to the box. I'm supposed to buy the whole box for $2,500. I am not supposed to be doing any of this and it is 'certainly none of my business'.

And it's matched to a Kubota engine so if anyone would have it they would, although they are pathologically unable to find anything unless I already have the part#.

Plus this is pollution-control and a very special device constructed for a particular function and certified as a unit. If there were any chance of finding who actually makes it maybe, maybe I could buy from them but chances are slim for all of this, I think.

Having gone over Epcos' whole product line of pressure sensors, this one looks like it has the characteristics needed:
Date: 2009
Pressures: 100 - 6000 mBar
Connections: 3, potentiometer

Only thing is I don't see how the formfactor could fit in the case I have, and I don't want to tear it open to see the die.

I've put in an inquiry to Epcos, although I'm sure I'll never hear back on something like this.

Edit: whoah whoah whoah... Looking at the datasheet under Ordering Codes, my second number sure looks like an Epcos part#, if we pretend the 'S' is a '5'.
B58621M3200B021

I've gotta say it is my part#. Searching on it I get a couple Asian hits, but maybe I can order free samples of it from Epcos now that I have the part#.

 

[BigWrench55]

I hope all goes well with you. If that doesn't work then take the aftertreatmeant s.n.# and go to Cummins quick serve website and look it up. I am pretty sure that Cummins has designed the system.

 

[Quantum]

Paul where would the aftertreatmeant s.n.# be? There don't seem to be any markings on the DEF pump box.

 

[BigWrench55]

It will be on the SCR.

 

[Quantum]

Whelp... there is just no other way to say it, and there is no other reasonable conclusion that can be reached:







YOU GUYS ROCK!!!

I fixed it last night.

I didn't get any response to my sample request from the sensor company, so I just presumed that I had -not- damaged the sensor, and reinstalled it in the DEF pump box after carefully cleaning out the DEF crystals WHICH WERE THERE.

I started the engine and DEF pressure was around zero then bumped to .4psi. It bumbled around there for a bit, then came up to 14psi. It went like this for a bit and I says to meself 'this is all I'm going to get'. Then it went to 20, then 24. And then 50.4! My god, I've never seen this. Then 80! I could not believe my lying eyes.

I thought well my gosh, the Inhibit on DPF regen must be gone now, so Service|ManualRegen and it claimed it'd started, but then it's always done that.... but oh, engine speed just ramped up! So I went to Info|Status, and By The Mighty Hammer of Thor, it was in regen!

A thousand degrees! Wow. I don't understand how it could get this hot, even if it bypasses the turbo. It must be using some other method.

It was very low on fuel but I let it complete the regen cycle and idle back down (~45 minutes), and now DPF load is 32%, which I believe is normal. I looked at the two reset DPF settings, but they seem to be only for when the DPF is physically cleaned so I didn't touch them. Hopefully all is good now, and there are no errors. (Hate that infernal beeper now, I guess like I'm supposed to)

I took it out for a spin on neighborhood streets, and no derate for the first time! What a relief. Neighbors seem to enjoy seeing me driving it, and I have its name in big letters on the arms: 'BLUTO'.

So there you have it. It is possible to clear a plugged DEF system with the methods I've described. But I would have lost my sh*t and defaulted to buying scary-expensive parts if it weren't for you guys. Thank you.

I have one calibration left to do, hydrostatic (traction) valves. I tried doing this without reading the directions and the machine shot forward 30' before I stopped it! Seems you're supposed to block it off the ground for this cal, lol.

Then I'll temporarily install a substitute high-rez backup camera from eBay to see if it works, since the Cat camera went blind, and if so put that in permanently. And I'll install a 2300w inverter in the back door for a chainsaw, and I'm ready to go to work.

 

[92U 3406]

These aftertreatment systems use a catalyst upstream of the DPF. Anyone in the know feel free to correct me but my understanding is that there is a fuel post-injection during regen and the extra little bit of fuel reacts with the DOC catalyst to make those high temperatures.

 

[BigWrench55]

That is great news. You have shown determination that I have never seen before. You deserve half as much of the gratification if not more. Enjoy your skidsteer.

 

[Baytril]

Did you have to replace the pump or are you still running the same one