Soot Level Rising Fast while driving 2014 Volvo 670 D13 What could it be?

I've had this happen, but it can be a number of things. In my case, it was a bad injector.

 

I had the same problem, pinhole leak in my CAC. I would get them to do a monitored regen again and rule that out, but of course this could be a lot of things on an emissions tractor.

 

The way I found out was to rule everything else out first. I had the DPF taken apart and cleaned just in case. It wasn't even close to plugged, so I moved to the EGR system next. I was getting high exhaust temperatures as my soot gauge was rising, and I think it was because the spring in the EGR valve was weak and allowed the valve to open under boost. I had it replaced, and everything went back to normal for about 800 miles. Then injector #2 went out, and the soot level started acting up again, although the exhaust temperatures stayed low, unlike with the EGR valve. There was also the noticeable misfire while the engine was running. Before I replaced the EGR valve, I was kind of hearing a misfire/rattle noise when I would lightly accelerate, so I think the injector was acting up all along, and I didn't know it was a problem until it went out for good.

What you can do to troubleshoot your EGR valve would be to take a rubber glove and put it around a pipe coming out of the EGR cooler. Then you disconnect the plug that powers the EGR valve so that it doesn't open when you turn on the truck. If you start the truck and the glove inflates, then you've got a leaking EGR valve.

The first time my soot gauge was acting up, it was because of plugged up ports on the venturi tube. In that instance, the turbo would not hold pressure steadily. It would bounce between 5 PSI up and down around where it should be, and you could hear the turbo kind of surging and lagging.

If your truck is completing a regen and the temperatures are within spec, then I probably wouldn't look at the 7th injector as a problem. I took mine off and cleaned it up and replaced the gasket, but I didn't expect it to fix anything. It's just something I do preventatively while the DPF was off getting cleaned. I think 2014 and up have an AHI module that controls the fuel pressure to the 7th injector. There are a couple of valves and springs in there that are susceptible to getting blocked up if you don't change your air dryer cartridge regularly. Since you're not having problems completing a regen, I don't think there's an issue here, but it's something you'll want to keep on top of.

I think exhaust or boost leaks might mess with your pressure sensor's readings. If the computer believes you're normally supposed to have 25 PSI, but you really have 20, then the differential pressure sensor on the DPF is going to interpret that as a 5 PSI restriction, or whatever it uses calculates that. It can work similarly with an exhaust leak. If any pressure is lost between the sensor and the engine, it will read that as a restriction. I had mine tested when I was troubleshooting my soot gauge. You'll usually notice worse power and fuel mileage, and sometimes a noise with a boost leak. Exhaust leaks will be soot around the affected area. Boost test will be pressurizing the intake system and spraying everything with soapy water, and exhaust test will be putting smoke into it and seeing where it comes out of.

 

Start with the glove test for your EGR valve. It costs you a rubber glove and you can do it yourself.