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[feeutfo]

It's been fine in the cold, very slight grumpiness on tick over below 3c but sorts itself when properly warm.

Until this morning. -2c temp on the CID.  Get on the motor way, up to speed. Smell of gas in the car. Look at the control switch and the green light is flashing as if waiting to change over. Which It normally would have done a good 5 mins before. Turn the system off due to the smell, so no lights on the control unit at all. 20 odd seconds later the gas smell has gone. Continued on petrol (sob) to get go work.

 I can't say if it turned to gas or not at any point previously as I never bothered to check.

Leave work expecting to find a leak under the bonet. No smell after it switched over. Drive home on gas no problem. Can't find anything wrong. Odd. 


While on the subject, would lagging the coolant to vap pipes help the slight grumpy idle on cold mornings, until fully warm...? Not that I'll bother, tbh. It's a bloody mare for access down the side of the engine bay. It was awkward enough first time round. 

[Kevin Wood]

I doubt lagging pipes will make any difference. Your main problem is a ruddy great engine block and 10 litres of stone cold coolant.

If the vap is not hot enough you won't get enough vapour pressure. Very much doubt it'd affect idle but when the fuel demand is greater it would just switch back to petrol, IMHO. Maybe that's what happened. I imagine your commute is straight onto the motorway from cold. So, constant, high demand for vapour before vap is hot enough might just cause it to drop down below your switchover temperature, although I'd expect it to then resolve itself.

Could be that the vap froze up completely (did the heater stop working?) in which case it might take a while to thaw.

Doesn't explain the smell, unless some liquid in the system then boiled off after the vapouriser and raised the pressure so high that it forced its' way out somewhere.

First thing to do is a thorough check for leaks IMHO.

If that looks OK, try the journey again in similar conditions with the LPG software logging what's going on.

What switchover temperature do you currently run?

[feeutfo]

Woo, 40c and 40 seconds maybe? I would have to check to be sure.

[feeutfo]

And no issues with heater.

[Kevin Wood]

Woo, 40c and 40 seconds maybe? I would have to check to be sure.

That should be no problem. Mine is down at 25 ish and it doesn't miss a beat in any weather.

[JamesV6CDX]

Woo, 40c and 40 seconds maybe? I would have to check to be sure.

That should be no problem. Mine is down at 25 ish and it doesn't miss a beat in any weather.

Same temp for me

[feeutfo]

It was set at 30c and 30 seconds, but both this and the previous car would experience a "stalling in the middle of the road while trying to nip out into traffic" type problem at the end of my road on cold mornings.

[cem_devecioglu]

Chris , I'm not an lpg expert .. but before everything , find the location where it leaks asap.. a handy sensor in shops will help..

[TheBoy]

My 3.2 is grumpy when cold as well. I think the new setups are more tedious to set up right.  Might have a play with the temp multiplier adjustment.  Then again, I might just leave well alone until a grown up is available - feel exposed not having a spare car

[tigers_gonads]

It was set at 30c and 30 seconds, but both this and the previous car would experience a "stalling in the middle of the road while trying to nip out into traffic" type problem at the end of my road on cold mornings.

I've got mine set to 25 degree's and 30 seconds and have never experienced anything like that 
What was your gas pressure like at idle when warmed through ?

[Lazydocker]

What size are your nozzles Chris? TB, we know yours are wrong

Both cars could probably benefit from a re-tune to be fair

[feeutfo]

What size are your nozzles Chris? TB, we know yours are wrong

Both cars could probably benefit from a re-tune to be fair

same as yours .. 2.3 is it?

[Entwood]

I know my system is totally different to the one you guys are using, in many aspects, so this may/may not be of any use .......

I had a similar problem some days ago night (morning ?? it was 0130), the OAT was -7C ... obviously the changeover took a tad longer than normal, but only by about 1/2 a mile, however instead of being almost un-noticeable there was a definite "cough" feel to the changeover, which lasted a few seconds, and a distinct smell of gas .... enough to cause concern ..... no lights or warnings anywhere ... smell went after about 3 minutes. No problems later that day in changeover/smells whatever. I checked the whole pipework with soapy water later .. no leaks found. Put it down to "one of those things".

Last saturday also had to drive in very cold .. -6C this time and the same thing happened ..... again no signs of any problems .....

Examining the system it occured to me I might know the cause, and I put it as my theory ......

on my system the vapouriser is down by the horns .. front left of car, with a significant pipe run from the vapouriser to the injectors. The vapouriser gets heated, the pressure rises, the system switches to gas, but the pipework from the vapouriser to the injectors is still significantly cold and the gas pressure drops for a short while, this causes insufficient gas at the combustion chamber and so misfires occur, the smell is the unburnt gas from those misfires ... as the vapouriser continues to work the pressure catches up with the normal requirement in a couple of seconds and everything works as normal....

Now, that is my theory, and I'm more than happy for it to be shot down .. but it might well be close to correct, and some elements could transfer across to your systems, as in slow to rise pressure due to abnormally cold pipework from the vapouriser to the injectors for a short time on changeover, especially as I believe your changeover is based on TIME and not on PRESSURE as mine is ??

Tin hat fitted awaiting incoming !!!

[feeutfo]

Gave it the berries this morning, running a bit late.

Behaved perfectly, no problem at all. Air temp was about minus 2c.

Only differance was I got cought at the lights onto the dual carriageway. So a bit more heat soak into everything.   

[Kevin Wood]

Thinking about this some more... We went out on a very cold day last weekend and noticed a smell of gas at about the time the car would have switched over. It switched cleanly without a misfire or anything, and the smell was only there for a couple of seconds. Assumed I'd passed a leaking gas main or a knackered Potterton like my neighbours' which sits there with the pilot unlit for hours.

My thinking is that, if the car is running, there's at least a partial vacuum in the whole intake setup so I can't see a way for gas to escape at the front end once it's injected. Yes, with a misfire you'd get a little out of the exhaust, but I can't see that finding its way forward to the scuttle area and into the cabin. That leaves a leak at the front end, but on several different cars and only in those specific circumstances?

I wonder whether, if the vapouriser isn't quite hot enough, liquid is admitted from the tank but takes a bit longer to boil off, so pressure is low initially and once it has risen enough to stop the flow of liquid there is enough boiling off in the vapouriser to cause an over-pressure. At this point, the ECU will be waiting for vapour pressure to build before switching the injectors on, and even then does so one cylinder at a time, so there is nowhere for the pressure to go other than to force its' way out through a connection somewhere.

Thing is, we're taking about a liquid that boils off at -40, so why would there be much difference between 0C and -5C outside temp? Especially when the vapouriser has heated to the switchover temperature regardless of the outside temperature.

Hmm.

Need to get a laptop on it and watch what happens at switchover when it's really cold, IMHO.