2007 International School Bus Parked Regen

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Well it started out alright until I found out the soot level in the diesel particulate filter was at a level 5 indicated in the software readings. That is the maximum level which means the chances of cooking out the soot to conservative levels is probably not going to happen. In fact the regen never took place. The high idle stayed up but eventually the software just kicked out and would not allow the process to go to the end. This means removing the DPF and taking it to an authorized dealer who has the cleaning equipment.

I received some good news from the dealer who told me the DPF was ready and could be picked up anytime. This means we don’t have to spend over 2000 dollars on a new unit. Around 400 dollars is the average cost for cleaning which is obviously the best way to go especially if you have a fleet of diesel engines to maintain. I’m surprised how long the average DPF lasts considering the goop that collects inside the filter.

The Diagnostic Link 8 software works very well with our Mercedes MBE 900 diesels. Mercedes, Thomas Buses and Freightliner are all one company so it makes sense for them to run school buses with the Mercedes. The problem with these diesel models was when emissions started back in 2007. The predecessor Mercedes engine block was re-engineered to accommodate the emission parts like the EGR valve, EGR cooler, electrostatic oil separator and so on.

The older Mercedes are more dependable than emission controlled models simply because there are way less working parts and trying to keep the engine clean reburning exhaust to reduce NoX is way more complicated. Of course now this diesel engine is out of circulation because it could not keep up with the EPA emission standards. We have many Mercedes diesel engines in our fleet and know them very well having years of experience repairing them. The exhaust and charge air system have to be sealed with no leaks or the system will code with a 2631 which indicates something isn’t working up to speed.

It’s good to know because power loss is something we don’t need. The on board diagnostics is there to protect the engine and sense any loss of performance. So sometimes engine codes can be your friend detecting an issue while it’s in the early stages. So our bus in the video will be getting a serviced DPF installed back in it’s belly and the flow of exhaust will be back to normal. Flow and resistance matters when it comes to emission controlled diesel engines.