Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: TheBoy on 06 June 2010, 10:39:59
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Not my car.....
Live data, when idling on LPG, short term fuel trims tend to go up to 15-20 on each bank. Flick back to petrol, and it starts to drop back to 0.
Hold revs at 2k rpm, long term fuel trims go up in to teens (short term stay around 0) on gas, again tend to settle nearer 0 when on petrol.
Is this just the LPG calibration being out?
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What size are the manifold nozzles TB?
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Is this just the LPG calibration being out?
Yep. I find mine wanders around a bit more on LPG than petrol. Does sound like that's got a consistent problem though.
Kevin
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Is this just the LPG calibration being out?
Yep. I find mine wanders around a bit more on LPG than petrol. Does sound like that's got a consistent problem though.
Kevin
I'd agree... We noticed mine wandered a bit IIRCC
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Speaking of calibrations, Mr Wood, I may need to borrow your good self up in the lakes for half an hour, suspect mine needs recalibrating/tweaking (based on its done a couple of thousand now).... ....and the firmware is about 4 version out of date ;D
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No problem. :y
Will try to remember to install the latest version before I leave.
kevin
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its my car, thanks TB, so i guess raise the Vap pressure half a bar at a time and re calibrate until lpg fuel trims match petrol ? should be able to do that with elm cable etc.
I need to fiddle with it as it bogged badly at the end of my road, hot weather caused early switch over to gas just as i hit the pedal to pull out into a gap in the traffic, not good. :o
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its my car, thanks TB, so i guess raise the Vap pressure half a bar at a time and re calibrate until lpg fuel trims match petrol ? should be able to do that with elm cable etc.
I need to fiddle with it as it bogged badly at the end of my road, hot weather caused early switch over to gas just as i hit the pedal to pull out into a gap in the traffic, not good. :o
Interestingly, I've dropped my vap pressure to 1 BAR for an experiment and it seems better, although I had the early switchover and bog down issue whilst in Yorkshire... I put the main problem being that I had next to no LPG in the tank (I'd run out on the way in the previous evening) and the early switch meant that the car's ECU was still applying enrichment which isn't needed when running on LPG. It actually stalled and was not a convenient time, travelling uphill! It did smell very strongly of petrol when it re started for a few seconds too!
Still... I wish we could get to the bottom of this niggle because it's getting very frustrating! :(
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its my car, thanks TB, so i guess raise the Vap pressure half a bar at a time and re calibrate until lpg fuel trims match petrol ? should be able to do that with elm cable etc.
I need to fiddle with it as it bogged badly at the end of my road, hot weather caused early switch over to gas just as i hit the pedal to pull out into a gap in the traffic, not good. :o
Interestingly, I've dropped my vap pressure to 1 BAR for an experiment and it seems better, although I had the early switchover and bog down issue whilst in Yorkshire... I put the main problem being that I had next to no LPG in the tank (I'd run out on the way in the previous evening) and the early switch meant that the car's ECU was still applying enrichment which isn't needed when running on LPG. It actually stalled and was not a convenient time, travelling uphill! It did smell very strongly of petrol when it re started for a few seconds too!
Still... I wish we could get to the bottom of this niggle because it's getting very frustrating! :(
it is indeed frustrating, some input from Tilo needed by now surely, i think between us we've tried enough settings to conclude we cant get rid, just move it about under certain conditions.
Had about 1/3 of a tank when it bogged setting off to Ashridge meet.
....and of course i mean .05 of a bar at a time, not "a" Bar at a time.
Trouble is i have no idea what to do with this mapping business. Calibration seems accurate and easy enough, but the last few tweeks while driving....plus i need a decent driver if i'm play on the lappy.
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its my car, thanks TB, so i guess raise the Vap pressure half a bar at a time and re calibrate until lpg fuel trims match petrol ? should be able to do that with elm cable etc.
I need to fiddle with it as it bogged badly at the end of my road, hot weather caused early switch over to gas just as i hit the pedal to pull out into a gap in the traffic, not good. :o
Interestingly, I've dropped my vap pressure to 1 BAR for an experiment and it seems better, although I had the early switchover and bog down issue whilst in Yorkshire... I put the main problem being that I had next to no LPG in the tank (I'd run out on the way in the previous evening) and the early switch meant that the car's ECU was still applying enrichment which isn't needed when running on LPG. It actually stalled and was not a convenient time, travelling uphill! It did smell very strongly of petrol when it re started for a few seconds too!
Still... I wish we could get to the bottom of this niggle because it's getting very frustrating! :(
it is indeed frustrating, some input from Tilo needed by now surely, i think between us we've tried enough settings to conclude we cant get rid, just move it about under certain conditions.
Had about 1/3 of a tank when it bogged setting off to Ashridge meet.
....and of course i mean .05 of a bar at a time, not "a" Bar at a time.
Trouble is i have no idea what to do with this mapping business. Calibration seems accurate and easy enough, but the last few tweeks while driving....plus i need a decent driver if i'm play on the lappy.
I didn't re-map mine last time, just calibrated it and went for a run, checking the map as I went.
It's still lagging slightly, but more like we got on yours in Essex, with just a slight hesitation instead of the full blown (albeit brief) loss of power.
As for Teilo... I've not really tried to get hold of him lately. In fact, I've not really had chance to get on here much either due to other commitments :(
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its my car, thanks TB, so i guess raise the Vap pressure half a bar at a time and re calibrate until lpg fuel trims match petrol ? should be able to do that with elm cable etc.
Don't need to touch the vapour pressure. It will just be fine tuning of the map that it needs. ;)
Do another auto-calibration if you like, just for good measure, clear both curves in the map display, collect a curve on petrol and then one on LPG, adjust until they match. :y
Kevin
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Or.. Disregard the mapping screen in the AC software and tune it for minimal fuel trim using the OBDII display.
Kevin
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its my car, thanks TB, so i guess raise the Vap pressure half a bar at a time and re calibrate until lpg fuel trims match petrol ? should be able to do that with elm cable etc.
Don't need to touch the vapour pressure. It will just be fine tuning of the map that it needs. ;)
Do another auto-calibration if you like, just for good measure, clear both curves in the map display, collect a curve on petrol and then one on LPG, adjust until they match. :y
Kevin
It seems that the maps drift more than I expected over time... I had mine spot on last time and when I looked the other day the LPG map had drifted North a little... Still well within the 10% deviation line but had drifted none the less.
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Or.. Disregard the mapping screen in the AC software and tune it for minimal fuel trim using the OBDII display.
Kevin
Now that would be an interesting approach... I'd be interested to hear the results of tuning it that way.
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It seems that the maps drift more than I expected over time... I had mine spot on last time and when I looked the other day the LPG map had drifted North a little... Still well within the 10% deviation line but had drifted none the less.
I think it's not an exact science mapping against the measurements in the LPG ECU. Different weather, road conditions, etc. during calibration will affect it.
Also, if you rely on the petrol curve that has built up over time that will have mostly been collected during warmup and, probably over the little bit of pottering around you do after each startup before hitting the open road, so it's always a good idea to clear that, do a run on petrol and then lock the petrol curve before looking at the LPG curve.
Also - you are mapping in 2 dimensions only. Injector duration versus manifold vacuum.
I suspect that, for each combination of the two, there are several driving conditions that can reproduce them, with slightly different calibration requirements which is where you are relying on the main ECU to trim the fuel.
I will have to look at mine sometime. At the lakes if not before. Mine literally hasn't been touched since a couple of weeks after I converted it. :-X
All I know is that the fuel trims have stayed within reasonable limits, so it can't be that bad.
Kevin
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It seems that the maps drift more than I expected over time... I had mine spot on last time and when I looked the other day the LPG map had drifted North a little... Still well within the 10% deviation line but had drifted none the less.
I think it's not an exact science mapping against the measurements in the LPG ECU. Different weather, road conditions, etc. during calibration will affect it.
Also, if you rely on the petrol curve that has built up over time that will have mostly been collected during warmup and, probably over the little bit of pottering around you do after each startup before hitting the open road, so it's always a good idea to clear that, do a run on petrol and then lock the petrol curve before looking at the LPG curve.
Also - you are mapping in 2 dimensions only. Injector duration versus manifold vacuum.
I suspect that, for each combination of the two, there are several driving conditions that can reproduce them, with slightly different calibration requirements which is where you are relying on the main ECU to trim the fuel.
I will have to look at mine sometime. At the lakes if not before. Mine literally hasn't been touched since a couple of weeks after I converted it. :-X
All I know is that the fuel trims have stayed within reasonable limits, so it can't be that bad.
Kevin
I must confess, mine never seems to drift too far unless I've been messing about with parameters etc to try and get rid of the lag. Much better with lower pressure but I may have to up it slightly if I get a repeat performance of the cutting out ::)
Think it was just down to being very hot... But we'll see ;)
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When you say an "early switchover" are you taking about switching over to LPG too early after a startup or switching back to petrol before tank is empty?
On the former, I've set mine up to switch over after 30 seconds / 20 degrees C. In this weather it's on LPG by the time I get to the end of my road and it pulls happily when I hoof it out of the T junction. ::)
I have never experienced the latter at all. Then again, I'm running 1.25 bar IIRC. What do you have the "switch to petrol" pressure set to? I wonder if it needs to be lower, with a lower pressure setting?
There is probably some further diagnostics we can do with these running issues but we need better tools than the datalogs we can get out of a tech 2 or the LPG software.
I wonder if we could jury rig a car for some better monitoring of a few of the signals? Hmmm. Need a nice data acquisition card in a laptop, I think. Failing that a scope in the passenger footwell.
Kevin
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Think I may need to set mine back to 30 seconds... IIRCC it's currently 10 secs and it's too soon in this weather... The car's ECU is still bunging a load of (unnecessary with LPG) enrichment in ::)
I think I had to do the same last year too... I wonder if 20 seconds is enough
Switch back pressure automatically adjusts when you adjust the Vap pressure and re-calibrate IIRCC
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In the hot weather last week, I pulled out of my parking space, went to hoof it out of carpark, and it bogged down. Mine set to 10s iirc :o. Might up it to 30s ;D
As to gearbox changes and hesitations - mine has only done it once or twice (one may have been me confusing gearbox with erratic throttle ::)), not sure how to provoke it?
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As to gearbox changes and hesitations - mine has only done it once or twice (one may have been me confusing gearbox with erratic throttle ::)), not sure how to provoke it?
ISTR that we set your pressure to about 1.06 BAR, which seems to be about the most reliable pressure. As for provoking it... It only seems to happen when changing gear over 5200ish RPM but is ok if taken right to the red line with the pedal buried. Can also be provoked if you come off the throttle and back on again in quick succession at very high RPM.
You checked the oil pressure on the silver bullet yet?
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I shall try to provoke it tomorrow.
Oil pressure? Was I supposed to do something ::)
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yeah, see, i was doing well until we started talking about mapping, locking curves, and tweaking, no idea with all that.
When you say an "early switchover" are you taking about switching over to LPG too early after a startup or switching back to petrol before tank is empty?
in my case, it was switching over too early that caused the problem, due to the higher air temps lately. Usually its a couple of minutes until gas clicks in, well down the main road, but this time it must have clicked in just as i pressed the pedal, and bogged instantly leaving me sat on the white line going nowhere.
I haven't had it switch back to petrol for a while, until its empty of course. ::)
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I shall try to provoke it tomorrow.
Oil pressure? Was I supposed to do something ::)
Come on... Is it all healthy again or still having to be treated gently? I may well have missed something during the last few weeks as my time on here has been incredibly limited :'(
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yeah, see, i was doing well until we started talking about mapping, locking curves, and tweaking, no idea with all that.
When you say an "early switchover" are you taking about switching over to LPG too early after a startup or switching back to petrol before tank is empty?
in my case, it was switching over too early that caused the problem, due to the higher air temps lately. Usually its a couple of minutes until gas clicks in, well down the main road, but this time it must have clicked in just as i pressed the pedal, and bogged instantly leaving me sat on the white line going nowhere.
I haven't had it switch back to petrol for a while, until its empty of course. ::)
At least it looks like we may have cured one problem then! Up the changeover time to 30s as Kevin says and see what happens... I'll be doing the same :y
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I shall try to provoke it tomorrow.
Oil pressure? Was I supposed to do something ::)
Come on... Is it all healthy again or still having to be treated gently? I may well have missed something during the last few weeks as my time on here has been incredibly limited :'(
Was I supposed to be treating it gently ::)
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I shall try to provoke it tomorrow.
Oil pressure? Was I supposed to do something ::)
Come on... Is it all healthy again or still having to be treated gently? I may well have missed something during the last few weeks as my time on here has been incredibly limited :'(
Was I supposed to be treating it gently ::)
Guess that means it's OK now then? Did you get to the bottom of the problem or did it just need another oil and filter change?
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I shall try to provoke it tomorrow.
Oil pressure? Was I supposed to do something ::)
Come on... Is it all healthy again or still having to be treated gently? I may well have missed something during the last few weeks as my time on here has been incredibly limited :'(
Was I supposed to be treating it gently ::)
Guess that means it's OK now then? Did you get to the bottom of the problem or did it just need another oil and filter change?
Errr, uhmmm, yes, I was going to change the oil, wasn't I. Job for the weekend methinks ::)
Apart from normal weekly checks, not even sure the bonnet has been opened :-[
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Hmmm....
KW/LD, do you remember when we were calibrating my car on one of the high speed runs, it got grumpy, and KW saying "better slow down, something don't look right"?
Happened again today, similar speed, mucho grumpiness. As it happened, traffic forced me to slow down just as I manually went back to petrol.
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Remember it... Yep.
So, it all got noisy again?
Don't think it's a LPG related problem... Still think it's oil thinning too much/starvation due to relief valve sticking etc?
Time to get a pressure gauge on I think :-/
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Remember it... Yep.
So, it all got noisy again?
Don't think it's a LPG related problem... Still think it's oil thinning too much/starvation due to relief valve sticking etc?
Time to get a pressure gauge on I think :-/
I think its fuelling. Suspect it won't happen on petrol. Possibly reaching the limits of single hole tank at, errr, 70mph.
Think the lifter issue is unrelated to that....
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Remember it... Yep.
So, it all got noisy again?
Don't think it's a LPG related problem... Still think it's oil thinning too much/starvation due to relief valve sticking etc?
Time to get a pressure gauge on I think :-/
I think its fuelling. Suspect it won't happen on petrol. Possibly reaching the limits of single hole tank at, errr, 70mph.
Think the lifter issue is unrelated to that....
Sorry, we were talking about 2 different things ::) :-[
Could be the limits of multivalve... But Chris' doesn't lean out at WOT so yours should be OK :-/
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Remember it... Yep.
So, it all got noisy again?
Don't think it's a LPG related problem... Still think it's oil thinning too much/starvation due to relief valve sticking etc?
Time to get a pressure gauge on I think :-/
I think its fuelling. Suspect it won't happen on petrol. Possibly reaching the limits of single hole tank at, errr, 70mph.
Think the lifter issue is unrelated to that....
Sorry, we were talking about 2 different things ::) :-[
Could be the limits of multivalve... But Chris' doesn't lean out at WOT so yours should be OK :-/
Mine doesn't in 1st and 2nd when I last checked. Wonder if it is when foot flat to floor, after its popped into 4th. Inst MPG is 7.1mpg at this point.
Hopefully Kevin will remember what he saw on the sensors....
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Sorry, been sitting in airport corridors courtesy of Easyjet this week. >:(
Yes, I remember the problem. It was a hard misfire at 5-6000 RPM IIRC. <cough!> must have been in 1st or 2nd gear, then? ::)
I don't remember it going lean and I was watching the lambda outputs at the time, all solidly on the rich side. Vapour pressure was pretty stable, IIRC.
I thought at the time that it might have been related to the issues the engine had - i.e. something had let go, but it all went back to normal after lifting off.
Ignition issue would be my first thought. Can it be provoked at all on petrol?
Kevin
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Sorry, been sitting in airport corridors courtesy of Easyjet this week. >:(
Yes, I remember the problem. It was a hard misfire at 5-6000 RPM IIRC. <cough!> must have been in 1st or 2nd gear, then? ::)
I don't remember it going lean and I was watching the lambda outputs at the time, all solidly on the rich side. Vapour pressure was pretty stable, IIRC.
I thought at the time that it might have been related to the issues the engine had - i.e. something had let go, but it all went back to normal after lifting off.
Ignition issue would be my first thought. Can it be provoked at all on petrol?
Kevin
That's my recollection too.... Although I was trying to lean forwards and look from the back seat ::) ::)
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Sorry, been sitting in airport corridors courtesy of Easyjet this week. >:(
Yes, I remember the problem. It was a hard misfire at 5-6000 RPM IIRC. <cough!> must have been in 1st or 2nd gear, then? ::)
I don't remember it going lean and I was watching the lambda outputs at the time, all solidly on the rich side. Vapour pressure was pretty stable, IIRC.
I thought at the time that it might have been related to the issues the engine had - i.e. something had let go, but it all went back to normal after lifting off.
Ignition issue would be my first thought. Can it be provoked at all on petrol?
Kevin
Yes, defo 1st or 2nd gear. 3rd would have been irresponsible ::).
This time it did it shortly after popping into 4th (about 2s later). It had gone through 1, 2 and 3 without missing a beat...
Not had the opportunity to try on petrol due to needing a good stretch of clear road.
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This time it did it shortly after popping into 4th (about 2s later). It had gone through 1, 2 and 3 without missing a beat...
Not had the opportunity to try on petrol due to needing a good stretch of clear road private test track.
;)
Just a quick misfire which cleared again?
Have you checked for codes? Just wondering if the crank sensor is struggling at high RPM (although I guess revs weren't stellar as it had just upshifted).
Kevin
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This time it did it shortly after popping into 4th (about 2s later). It had gone through 1, 2 and 3 without missing a beat...
Not had the opportunity to try on petrol due to needing a good stretch of clear road private test track.
;)
Just a quick misfire which cleared again?
Have you checked for codes? Just wondering if the crank sensor is struggling at high RPM (although I guess revs weren't stellar as it had just upshifted).
Kevin
Only code is the usuall 55 'Replace ECU' Not Present that I always get after she has used the car...