A Mitsi Fuso, a regular customer, and a hard cold start
A regular customer rolled their Mitsubishi Fuso into our Welshpool workshop the other day for its B service. While we were booking it in, he mentioned two things: a few lights out, and that the truck was hard to start on cold mornings.
Those little side-comments are usually the most useful part of the conversation. The B service was going to happen either way — but “hard to start when it’s cold” gives us somewhere to look once the routine work is done.
Why this matters
A hard cold start isn’t a quirk. It’s the engine telling you something isn’t right — and if you ignore it long enough, you end up with a truck that won’t start at all on the wrong morning. Cold-start issues also chew through batteries and starter motors, and they’re a real productivity hit when you’ve got a load to move at 5am.
Diagnosis — fault codes and a walk around the engine bay
First job on a B service is the walk-around. Lights, fluids, leaks, anything obvious. We worked through the list, fixed the lights, and noticed exhaust leaks around the EGR valve. That’s already a clue.
Plugged the laptop in and pulled the fault codes. The EGR system had stacked up a long list of them. EGR stands for exhaust gas recirculation — when the truck is hot or cold, the EGR valve opens and lets exhaust gases recirculate back through the intake. That keeps the engine in its happy temperature range and helps with emissions.
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The fix — a valve that should flick on a spring, but didn’t
We pulled the EGR valve off the engine. A healthy one sits on a spring and flicks open and shut when you move it by hand. This one was seized open. Wouldn’t budge.
That’s the cause of the cold-start problem in plain English. With the valve stuck open, exhaust gases were running through the engine the entire time, including from a cold start. The engine couldn’t get warm enough fast enough to fire cleanly. Cleaned the area, sorted the exhaust leaks, replaced what needed replacing, and the cold-start issue went with it.
Takeaway
Cold-start grumbles are usually pointing at something. EGR is one of the common suspects on diesel trucks, alongside glow plugs, fuel quality, and starter draw. If your truck’s hard to crank when it’s cold, get it looked at before it leaves you stranded on the wrong morning. Book it in or give us a call.