Starting differently

[sandancers]

We have a Mk7 fwd, 2.2 Euro5 2014.

A couple of years ago it would start immediately on turning the key, like the engine didn't even do one revolution and it was away. Clutch down, glow plugs allowed to heat up.

A fault occurred on one injector, so it was changed out. After that it was a bit difficult to start, then I traced down a open circuit glow plug, not changed it yet. The vehicle would turn over, catch and then die, a couple of re-tries and it was away. Not used very often so not a bother.

However, I have found by accident that if I press the accelerator, just slightly, when turning the key that the engine turns over, normal speed, without trying to start for a couple of revolutions, then catches, bursts into life and doesn't die ! Clutch down, glow plugs allowed to heat as before.

Any thoughts or theories ?

[tranmx2]

Check fuel filter for water. Check schrader valve above HP pump. Schrader is on the delivery to the HP pump.

Check exhaust colour.
Is the coolant level dropping, are there bubles in the coolant bottle when the engine is running?
Has the DPF been regenerated ?

The 4 glow plugs are activated when the ambient temp' is below aprox' 5 C.

Get Forscan and use Live data.

[sandancers]

Check fuel filter for water. Check schrader valve above HP pump. Schrader is on the delivery to the HP pump.

Check exhaust colour.
Is the coolant level dropping, are there bubles in the coolant bottle when the engine is running?
Has the DPF been regenerated ?

The 4 glow plugs are activated when the ambient temp' is below aprox' 5 C.

Get Forscan and use Live data.

Schrader valve OK. Not sure about water in fuel filter, what is the best way to check ?

Exhaust colour looks normal.

Coolant is fine.

Regen works fine.

The strange starting is not temperature dependant.

[T350camper]

To check for water in the fuel filter, get a small container (like the cap off a rattle-can) and hold underneath the filter. Slacken the yellow plastic wheel under the filter until liquid runs out. Catch it in the cap to inspect. You can see water as the diesel will bead and float on it. If it's clear it will all look the same and should be clear with a faintly yellowed colour as clean fuel.

[tranmx2]

A fault occurred on one injector, so it was changed out.

Was it the correct type of injector? Mk7s are not all the same.

[sandancers]

It was an independent Ford Transit specialist who changed the injector, proper old school mechanic, so I think it is done right. Vehicle runs great when started ! Starts slightly better when warm than cold.

No water in fuel.

[tranmx2]

The vehicle would turn over, catch and then die, a couple of re-tries and it was away. Could be due to pressure in HP system lowering.

Starts slightly better when warm than cold. Could be due to pressure in HP system being maintained near to required start pressure.

Could be leak on HP fuel line. Look at injector pipe esp both ends where the nuts are. A hair line crack could be sufficient. May see it is wet near to area of leak.
Be careful if looking with the engine running - HP diesel can enter your skin etc. A very light rag on a stick can be used.

Forscan - live data - can show the HP line pressure. Can be watched before start, during start, after starting the engine.