I'm curious as to why the tank level makes a difference. In theory, once the tank contains some liquid, it will be at the same pressure regardless of the level. Does the tank get excessively cold after a run on LPG?
This is the bit that I cant get my head around either, as you say pressure should be the same untill your running on fumes, and then it should cut out, which it does as per any other LPG system Ive driven.
So for me, 2 things, Level Sender or Temperature, for now Ive ruled the Tank Level sending, as it pretty much does what it says on the tin. Full Tank, half Full, Empty etc all fine (apart from Vauxhalls stupid "One fuel gauge does Both", which can take up to 10 mins to show the contents between Petrol and LPG on the same gauge, depending what position the LPG switch is, but thats normal).
With reference to the above replies, its probably also worth pointing out that the Flashing Green LED has 3 modes when its in the LPG ON position, Slow Flash = all Normal, running on Petrol, waiting for LPG to kick in, No Flash = running on LPG, Fast Flash = There's an Issue, Forced back to Petrol. Now, the only time it Fast Flashes, is when the Tank is Empty / Run Out and and its forced back to Petrol, ie, the issue is you've run out of Gas, all other times when it reverts back to Petrol as per the issue, the LED flashes normal, which also kind of confirms to me, that its not a Tank Sender issue or has thrown a Fault. Obviously if I tamper with it whilst on LPG, ie, unplug something, like Temp or Vacuum Pipe Sender it will revert back to Petrol and Fast Flash but that is only to be expected.
So Temperature, does a Full tank of LPG compared to a near Empty one deliver LPG to the Vap at a colder temperature, in theory no, in practice?, Im not clear on this, if does and the Vap is just about doing a catch up with its heat then that does kind of explain the issue.
Well, the coolant has made a difference, so that's a clue, in my book. Might be worth checking out how to clean the "heavy ends" out of the vapouriser, as it's possible that could affect its efficiency, making it over critical on coolant.
Ok, on the List, but why is it running perfect with half a Tank or less.
Also, worth jumping out and checking the vapouriser temperature when it switches back to petrol. If the vapouriser freezes up, the coolant passages will start to block, and it's a vicious circle.
Ive already checked this, the Vap runs from warm to cooler when switching back to Petrol, Not freezing, but cooler sometimes with some condensation present on the body after a run, should these things be hot, if so how hot?
Does it tend to switch back to petrol when under lots of load or when idling, or both?
Doesnt seem to make a lot of difference whether causally ploding along or flooring it, you kind of get a fill for it on distance, its almost like, after a mile or so you think its going to switck back to petrol now, and iy does.
If you park up with the engine running it will run all day long on LPG until you start to drive again, but I would expect this to be the case even under extreme cold weather, warm static engine bay compared to the chill factor when moving.