It wasn’t all that long ago a check of the oil pressure and temperature gauges was all you needed to determine if the big diesel in your machine was still running properly.
Diesels have earned a reputation as sturdy workhorses over the decades. But since the introduction of stringent emissions regulations, the mandatory exhaust after-treatment systems tacked onto them have given those venerable engines a finicky streak. I was reminded of that fact this past weekend.
A friend and I were driving a couple of highway tractors from Toronto to Winnipeg when a yellow check engine light popped up on the dash of one of them. No problem, the owner assured us. Just keep going. But after we stopped for a meal break in a small town in northern Ontario with sketchy cell phone service. That yellow light turned red and de-rated the engine. We were shut down.
The only repair shop in town had no diagnostic equipment and couldn’t help. But the owner did know a mechanic in a town 90 kilometres away that could come out and address the problem. Two hours later he showed up with his computer and logged into the truck to diagnose the problem. It turned out to be a faulty NOx sensor. The engine was fine. It was just an emissions system problem.
He cleared the code and forced the emissions system into regeneration mode to reset everything. After a five-hour delay, we were back on the road. But the next morning that yellow light was back. The only place we could get a full repair was a dealership three hours further down the road. We called ahead, but it was Saturday. They didn’t have a correct sensor in stock, and the Cummins warehouse was closed for the weekend.
So we could try to make it there and just wait, twiddling our thumbs until Monday, or we could go for plan B. It occurred to us the red light showed up only after we shut the truck down and restarted it after a break. So, we theorized, if we kept it running it might not go to red and de-rate the engine again. But that would mean we’d have to get home that day. A bit of simple math showed we barely had enough hours left in our logbooks. If we got westbound and down in a hurry and swapped meal breaks for a coke and a packet of M&Ms to eat on the way, we might make it.
We decided on plan B, which worked. With less than an hour of legal driving time left we rolled into a Winnipeg parking lot to deliver the rigs.
Sadly, emissions system problems like this have become commonplace in heavy trucks and farm equipment. Many people having a similar story to tell, be it about a truck, tractor or combine.
“You wouldn’t believe how often I have to do this,” said that small-town mechanic who came to our rescue. “I’m on call 24/7 just for this (correcting emissions system failures).”
We’re never going to get away from emissions systems, although some garages are pioneering a growing cottage industry of chipping computers and bypassing all those trouble-making emissions components. For the most part, though, we all have to learn to live with them. Sadly, expecting to eventually spend some time on the side of the highway or stopped in the field waiting for that mechanic and his computer to show up is now a fact of life for those of us living with this new generation of diesels.
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