Hello, the first thing to test is the glowplugs are heating ok and the glowplug relay timer is working.
Hi Mark, the first garage replaced an electronic black box which I was told was the Electronic Diesel Control EDC unit. After this was replaced with a new one (10 months ago), you could hear the revs change as I tried to start the bus when cold. However after a few weeks, the engine just reverted to turning over at a constant rate again. In the summer this isn't a problem and the engine starts first time. However, now the cold weather has started the problem has returned.
When I warm up the EDC the problem is still there. If I warm up the 'engine' on the same side as the EDC for an hour, the LT46 starts first time. Is there a sensor or relay connected to the EDC which I could locate and heat up in isolation ?
Actually it isnt the EDC which was replaced it was the 'electronic black box' ie the ECM Electronic Control Module ?
Is there a sensor in the EDC ? Might be worth warming that up in isolation to see if it works ?
I would replace the engine oil as it could be contaminated and too thick when cold. This can slow the starter down a bit and draw more current leaving the glowplugs with less. You still also need to check the glowplugs though.
Remember to use the correct grade of engine oil or one recommende for colder weather.
A 5/30W or 5/40W would be ok that meets VW505.00
Do you still need help with this?
I had the bus fully checked and serviced by 3 garages, including a VW main dealer. Oils were changed, filters replaced everything 'normal' checked and passed, but I still have the problem.
As I said the ECM was replaced. I have had many people suggest many things, including fitting an in-line bulk head heater and various other heaters to get around the problem. But it should work, a sensor, a relay must be effected by the cold. Do you know where you can get hold of manuals or info on LT46 ECM senors and where they are located ?
It is more likely that the heat under the engine is affecting the oil rather than anything else. Although you say the oil has been changed, do you know the grade of oil that was used. You also originally stated that the engine speed when cranking over was significantly different during cold spells compared to when the weather was warmer. This would suggest either incorrect oil grade, a bad battery or a high resistance in the earth cable. In my experience it is wrong oil grade.
I'll check the oil upgrade with the garage, and change the oil again myself anyhow. What is the best possible brand/type you would reccommend for something like this ?
Shell or Castrol Or Mobil 1 that meets VW505.00
A 5/30W or 5/40W viscosity.
Hi Mark, new to JustAnswer, do I rate each reply or at the end when I have tried the oil change ?
You just rate when you are satisfied I have been able to help.