LPG Discussion Forum

Hello all, could someone help with a couple of questions from a newbie? I have a newly self installed SGI system that I think is taking too long to change over when the car is cold in the morning. Within a mile and a half of starting the car I am driving at 50-60MPH on a main road and it can be as much as 2 miles before it changes over.Could this prolonged change over time be due to windchill ?? the reason I ask is that on my journey home from work I have to do a lot of stop start and low speed driving with which changes the engine over onto lpg at a lower engine temperature (shown on the gauge in the car) is this a simple tweak with a laptop to reduce the changeover temperature and can the problem be helped by the insulating coolant pipes and reducer to shield them from the wind . Generally the car gets up to temp quite quickly with the needle on the gauge sitting at the halfway mark and the heater blows very warm. Car runs fine on gas btw.
My second question is do I need flashlube fitting? car is a Fiat Bravo 1.2.

Thanks!

Few things. Firstly is the changeover set on acceleration or deceleration ? You may be cruising. And then not taking your foot off the throttle to make it change. You would need to monitor the temp in the morning via a laptop and see what's happening. Could be that your coolant plumbing is wrong. The reducer is too high. Or under the car and is indeed getting cold in the wind. Hard to say from here. Or it could even be your thermostat is duff.

Hello Tubbs, I have not noticed that the changeover point being related to whether I am accelerating or decelerating but will look out for that tonight. The coolant hoses are connected in parallel with the reducer mounted about halfway up the nearside inner wing and as I say, the heater blows hot quickly and the thermostat was recently changed for a Quinton Hazell unit, cooling system loses no coolant.
Can I download the programme and do the changes via an RS232 connection to the lpg ECU??

Many thanks

If the Bravo uses flap valves rather than a tap to adjust the heater temperature (as most modern cars do), then you can plumb the reducer in series with the heater. That way the hot water has to pass through both rather than possibly taking an easier route through the heater matrix. If you installed it yourself and don't have a lead and software, how did you calibrate it when you first fitted it? You'll need the lead as well as the software, have a look at www.wtv-uk.co.uk and see if they do one for your system.

oversteer wrote:Hello all, could someone help with a couple of questions from a newbie? I have a newly self installed SGI system that I think is taking too long to change over when the car is cold in the morning. Within a mile and a half of starting the car I am driving at 50-60MPH on a main road and it can be as much as 2 miles before it changes over.Could this prolonged change over time be due to windchill ?? the reason I ask is that on my journey home from work I have to do a lot of stop start and low speed driving with which changes the engine over onto lpg at a lower engine temperature

I find this as well, system changes over at any throttle position. Away from my house one way is 40mph limits, the other way 40 then dual carriageway after a mile. I'm sure it takes longer time & distance wise to switch over going up the dual carriageway. Assuming you work normalish dayshifts, I think the below is more relevant.

morning start, freezing nights, car not used for probably 12 hours.

After work, warmer temperature in the daytime, car not used for probably 8 hours.

Hi Folks sorry to 'bump' this post but I thought I might add something to this that may help others in the future.......

I have experimented with lagging the coolant pipes where possible (it's tight for space under there!) using plumbing lagging and also lagged the reducer to test if it was windchill by wrapping a couple of bits of carpet round it (this will be replaced with something non-flammable) the result is that the car switches over to lpg much earlier with the temp gauge at a around the quarter mark and within a mile of starting up from cold.

Interesting info and something to think about. In your case the problem with change over time could have been made worse by vapouriser positioning.

This may not apply to your set up - mine's very basic, but I have noticed it is quite sensitive to insufficient warmth soon after starting.
Having the vapouriser T's off from the heater pipes, it appeared to make a difference having the input pipe in the straight-through position rather than 90 degrees. Fluid passing over another pipe at right angles can actually suck backwards rather than blow.

I never turn the heater on until it has been running on gas for a while and has recovered from the temperature drop. Alternatively, if very cold and I want the heater, I delay switching over to gas again until the temperature has risen again.

I always force mine to switch over at a convenient moment, by switching, waiting a second or two, then declutching and gentle blipping the throttle. It's the deceleration after blipping that triggers the actual change in my case. If I simply switch and leave it, it will decide to change at some inconvenient moment, eg when pulling up at a junction and then wanting a quick getaway.

I time the moment of switching according to the air temperature. In mild weather the gauge is climbing after 1/2 mile, and it will change-over without any problems. In very cold weather I wait a bit longer until the gauge has reached normal after the thermostat has opened.
I have observed that the engine temperature can drop sharply for a few minutes after the thermostat cuts in. Timing the gas switchover at that point is not a good idea - it puts a double load on the heat output, triple if you turn the car heater on too. The vapouriser is the one that needs the heat.

On carb engines where you are starting on gas lagging the vapouriser might not be such a good idea as it will not be able to pull any heat from the surrounding air.

On the Volvo 240 I cut the water hoses where there is an elbow in the rubber. Putting the T's in there get about the best flow possible to the vapouriser