Mx13 head scratcher

[Perro903]

2016 t680.mx13

New customer asked if I could look at truck, sure why not. Pulled up, hooked up and retrieverd code. Many random codes. I clear codes and some of the previous come up and then some new ones. Every time I clear code new codes come up and some of the old ones go away then come back up later. The craziest part is there is no CEL only calling for a Regen. The egr has been blocked off but I do not know if it's "tuned" for it. I do not know the history of this truck. When I checked voltages and resistance on wires, from ecm and out of ecm, to the first sensors I got codes for (egr temp, temp after bpv, oil temp, and humidity) they checked out fine. After clearing couple of times those went away just to get a new set of sensor faults (coolant level, coolant temp, oil pressure, can communication on bpv, scr temps). Did nothing but reset fault. Maybe the ecm go bad?

[mikkhh]

Most if not all "tune" "mandate removal" solutions on those MX13 are plain garbage!!!!!!

First step to get it fixed and running properly look up how much for new dpf doser, new scr doser, new dpf/scr cans . If price for those is acceptable then have ecm reflashed to stock and then see what is actually wrong.

Remove all those blank off plates, fit new OEM back pressure sensor, boost pressure sensor, dpf differential sensor and have egr cooler cleaned/washed, clean intake with vacuum and it should work or at least show codes.

It is very common for newer MX13 engines to spin injector pump cam lobes even et 150 000miles. If they have fuel pressure fault codes do not replace pumps as a first step, remove pump and cups that ride on cam and look for wear. I usually like to warn beforehand about things that may be wrong, way better than other way of bad new that keep coming and coming.

[Perro903]

I didn't have any fuel sensor faults. Oil pressure to low, temp sensor after BPv shorted to high, oil temp sensor shorted to high, can communication bpv slow. Mostly temp sensors shorted to high. I check wiring to each sensor flagged test points at the sensor, from ecm, to ecm, voltage and resistance with and without load and put a resistor across the to trick ecm to read sensor but nothing changes in the live view.

[mikkhh]

For the MX's, Sadly there is no proper deman solutions out there for those. All your problems could be due to the programming that is made by somebody. Only proper solution for those as of now is to fix the mandate and keep it running stock. It has got ecm + acm (mounted on cans). ACM is made by red engine manufactirer and also other parts of emissions system too are designed by red engine company. Dpf dosers etc.

If just the cans had been gutted then outcomes might be little better. But full "solutions" like block off plates are absolutely terrible with their programming.

There is no silver bullet in acm either, absolutely no way to turn those things off there...

[Perro903]

10 4. That's the way I'm leaning because I don't know for sure it's programed for demandate. I found the block off plate at the end of my work on it. It was 1 am and I was ready to get to bed so didn't dig deeper. He just asked if I could look at it because if it was to much he was just going to sell the truck. I found some burnt wires caused by an exhaust leak so figured that was majority of the problem but nahhhh. I'll have to call customer and see all that was done to that truck . Thanks for the responses

[mikkhh]

Easy test for properly working mandate is check to see if tailpipes are sooty (I use finger to check and show result). If yes then there is problem going on, either cans are just done or somebody has gutted them. No cleaning or baking is going to fix those filters, if they have failed completely DUE TO lack of maintenance - cans need to be regularly dry cleaned in special kiln oven to keep them operating properly and for many years to come.

First thing to do on emissions equipped trucks regardless of make and model is egr tuneup that has to be done YEARLY to keep engine running properly. It can be hard for truck owner to understand the importance and justify the cost, since you may be one out of hundred who says that things like that have to be done.

Fixing things for people who want to fix things fixed cheapest way possible to sell on is not something that is easy also since there is going to be lots of crying about cost and cutting corners.

[Perro903]

Update, his "mechanic" probed wires in the ecm connectors and spread the contacts open where they were getting any voltages. Repaired. All codes went away. Fixed!!!...... NOPE, he called back the next day asking why I didn't fix the truck. Well apparently apparently that wasn't the main issue, main issue is truck would start up and die within a second. Turn key off, start up, die every time. I've fed u dye to find leaks but none showed, removed the check ball in filter tube out, and no codes. I pushed diesel in through the priming port at 40 psi and managed to get it running for a minute, killed fuel to priming port and it died. Turned the fuel back on to priming port and it's doing the same exact thing as without prime, crank and die. Idk about this one. With pressure on the priming port I have pressure, and retains the pressure, up until the lift pump after that I haven't checked yet. Any help out there?

[mikkhh]

Did you check camshaft for spun lobes? Very common issue, they have two high pressure pumps that are driven off of camshaft. With any fuel issues it is the first thing for me to check on those.

What about rail pressure? If you remove power to priming pump it stops giving out fuel? I use 5bar diesel car pre supply pump for priming, if you cut power to pump engine will cut out due to lack of fuel


What fault codes it has now? Rail pressure codes?