Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: feeutfo on 08 February 2012, 15:49:57
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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. ;D
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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?
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Woo, 40c and 40 seconds maybe? I would have to check to be sure.
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And no issues with heater.
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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.
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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 :y
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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. :-\
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Chris , I'm not an lpg expert .. but before everything , find the location where it leaks asap.. a handy sensor in shops will help..
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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 ::)
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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 ?
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What size are your nozzles Chris? TB, we know yours are wrong ;)
Both cars could probably benefit from a re-tune to be fair ;)
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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?
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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 !!!
:)
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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.
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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.
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I think Nigel may have a good point. I can't compare it with mine because it's got no Petrol and No LPG at the moment, buried under 4" snow and not been used at all for about 5 weeks, or in anger for 3 months :'( :'(
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If you can access mains near your parking
Fit a Kenlowe Pre heater
In half hour engine warmed by pumped round coolant
1 hour quite hot (can even feel the plenum warm)
Problem solved :y :y
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Some thoughts, all rubbish probably.
Something is a bit border line, another 10 degrees added to switch over temp has improved matters previously.
Add in a good blast on freezing but bone dry roads, could the air temp add some wind chill and cool something back down after switch over criteria has been reached.
I had thoughts of carb icing type scenarios on bikes. (yes I know it's injected etc but the symptoms where similar)
Should I tape up the rad? (I know the answer to this btw ;D )
Lag the coolant feed to vap? Although heater was fine, it kicks in from cold at the exact same point each morning, of its proper cold, like now it takes another 400 yards to kick in. Nothing more. Engine temp at 80 on the gauge in the cold. 90 in summer.
Lap top examination will be difficult at 5am on me own while driving. But your right, it needs checking over from stone cold. wonder if the LPG ecu has stored a fault code or error?
Theres a part of the software we don't use currently, to do with temp range. Do we need to be factoring this in? There does seem to be a seasonal side to LPG set up that maybe this could sort?
Noticed there was a slight hunt today. Engine warm. Well warm.
Trims where +/- 3 and 1 last I looked. No idea which way round but wasn't to worried by that. Although it was considerably warmer.
The blow by theory was on my mind as I smelled the gas in the car, and took an amount of time for the smell to disipate after turning the switch off tuat seemed to back up the theory.
If the vap was iced up would it block completely? If so the tank valve would be open and the vap blocked. Would this give enough back pressure to blow by? Is there a release valve? ( dont think so)What's that brassy looking lump that sits between the fuel line feed and vap inlet? Looks like filter, but isn't...is it?
Could the vap solenoid have stuck closed or failed to open?
My gut feeling was the LPG has switched on as normal, after 40secs. But had later encountered a problem and switched back, as the light was flashing. But no alarm. Sopignificant? :-\
No issues on return journey today either.
The leak must have been in engine bay somewhere.
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There is a pressure release ;)
The Brassy thing is a filter ;)
Other than that, it needs looking at on the Lappy ::) Might be worth us re-calibrating and mapping next time we meet up (supposed to be in the near future I believe, according to the ladies ::)) :-\