22-08-2016, 06:48 PM
M49, DW8 engine, Delphi injection pump.
This engine mostly runs perfectly, but occasionally when it's been sitting for a few minutes with a hot engine, for example after climbing a hill then stopping, it has difficulty restarting.
On turning ignition on, the battery voltage drop suggests that the glowplugs are working OK. On turning the starter, the engine fires immediately but rather weakly, and after a few seconds, peters out. Repeating the preheat doesn't help. Cranking the dead engine for 10-20 seconds gets it to fire up, after which it has to be coaxed with some throttle for a minute or so before it will idle on its own.
I've checked for water in the filter drain; none. There do not seem to be any air bubbles in the fuel return line. No obvious leaks from injectors.
The symptoms are very like a vapour lock on a petrol engine, but I don't imagine that applies here.
Did it to me in Asda car park today, tried to reproduce the fault once back at base, naturally all it would do was start every time.
Not a major issue at present, but I'm concerned that if I don't find out what's causing it, it will eventually quit altogether. Do quite a bit of hill walking, and if it quit somewhere remote, it could be mighty inconvenient.
-Any ideas?
This engine mostly runs perfectly, but occasionally when it's been sitting for a few minutes with a hot engine, for example after climbing a hill then stopping, it has difficulty restarting.
On turning ignition on, the battery voltage drop suggests that the glowplugs are working OK. On turning the starter, the engine fires immediately but rather weakly, and after a few seconds, peters out. Repeating the preheat doesn't help. Cranking the dead engine for 10-20 seconds gets it to fire up, after which it has to be coaxed with some throttle for a minute or so before it will idle on its own.
I've checked for water in the filter drain; none. There do not seem to be any air bubbles in the fuel return line. No obvious leaks from injectors.
The symptoms are very like a vapour lock on a petrol engine, but I don't imagine that applies here.
Did it to me in Asda car park today, tried to reproduce the fault once back at base, naturally all it would do was start every time.
Not a major issue at present, but I'm concerned that if I don't find out what's causing it, it will eventually quit altogether. Do quite a bit of hill walking, and if it quit somewhere remote, it could be mighty inconvenient.
-Any ideas?
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