Technical glow plug issue 3litre 2007

[cabmerlot]

hi guys
we just bought a motorhome with a starting issue...the problem is the amount of time the glow plug symbol stays on for....it goes off virtually straight away....i have replaced the glow plugs but that didnt alter the time the symbol stays on for....is this normal or is there some timer mechanism which can be replaced......since i started working on the van the weather has got warmer so not sure if van is starting as per
thanks
russ

 

[bugsymike]

hi guys
we just bought a motorhome with a starting issue...the problem is the amount of time the glow plug symbol stays on for....it goes off virtually straight away....i have replaced the glow plugs but that didnt alter the time the symbol stays on for....is this normal or is there some timer mechanism which can be replaced......since i started working on the van the weather has got warmer so not sure if van is starting as per
thanks
russ

There may be other issues rather than glow plugs preventing the vehicle from starting.
If it takes a long time cranking over before firing, do you get white smoke smelling of diesel from the exhaust?
If so then it can be a heater plug issue, but also can be low compression. The other name for a diesel engine is CI short for compression ignition, so in basic terms low compression = poor starting.
Diesels need high/good compression to get the air in the combustion chamber hot before the diesel is squirted in to ignite it.
If no smoke on cranking it may indicate fuel isn't getting to injectors to fire the engine, so another thing to check.
Going back to the heater plugs, did you test them and the power to them before replacing?
Is the engine high mileage or burning oil, this can indicate worn pistons and cylinders causing low compression and hard starting?
Does the engine spin over well on the starter, if slow cranking it can also affect starting?
Sorry to say , but there can be many causes for poor starting.

 

[cabmerlot]

There may be other issues rather than glow plugs preventing the vehicle from starting.
If it takes a long time cranking over before firing, do you get white smoke smelling of diesel from the exhaust?
If so then it can be a heater plug issue, but also can be low compression. The other name for a diesel engine is CI short for compression ignition, so in basic terms low compression = poor starting.
Diesels need high/good compression to get the air in the combustion chamber hot before the diesel is squirted in to ignite it.
If no smoke on cranking it may indicate fuel isn't getting to injectors to fire the engine, so another thing to check.
Going back to the heater plugs, did you test them and the power to them before replacing?
Is the engine high mileage or burning oil, this can indicate worn pistons and cylinders causing low compression and hard starting?
Does the engine spin over well on the starter, if slow cranking it can also affect starting?
Sorry to say , but there can be many causes for poor starting.

thanks for reply....i just need to know how long the symbol should be on for?

 

[bugsymike]

thanks for reply....i just need to know how long the symbol should be on for?

Often in warm weather it may not appear at all, however the heater plugs on many vehicle these days assist when vehicle doing a DPF Regen so well worth checking the function of the whole circuit not just replacing heater plugs.
I have noticed on many vehicles these days even in cold weather they only come on for 15 secs or less, though some will be visible during the warm up period in cooler weather.
As you probably know already the ECU controls heater plug operation through many sensor inputs, unlike in the old days.
I would say where I live we have very mild Winters so less of a test.
I put the older 2.8 Sofim Fiat Ducato engine in a boat and even with ice on the gunnels I could start the engine easily with no heater plugs connected at all. This was a 1997 2.8 iDT pre ECU as I didn't want any electrical issues several miles out to sea. It would always start instantly and ran it for four years.

 

[cabmerlot]

ah...thanks for that...15seconds

 

[Anthony489]

Hi

When you say a starting issue, do you mean that it actually starts OK but you are just curious at how short a time the glow plug light stays on ?

A 2007 engine will have glow plugs that each draw roughly 20 Amps at 11 Volts on initial switch-on. That's over 200 watts pumped into something not much bigger than a match head. Modern glow plugs therefore get up to working temperature much more quickly than was once the case, so the light may go out almost straight away in warm weather and after only a few seconds in colder weather.

As far as I know, for a 2007 engine the glow plugs are only used to aid starting below about 5 degrees C, and not for any other purpose.