Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: richard on 29 May 2010, 17:37:25
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Hope you good people may have some clues for me to follow
2.2 lpg/petrol 115000 miles 2003
Runs like a dream on LPG but a dog on petrol. Its been on tech 2 and Kevin cannot see any issues. Really hard to start but flips eventually to lpg and all ok..
Does it use the maf or O2 sensor when on lpg ??
Its got worse recently.. it was a niggle its now a real pain in the arxx. Tried redex to clean injectors etc. but seems to make no difference. The fact that all ok on lpg seems to suggest the spark etc is good as lpg normally much harder to ignite.
Every now and then it disappears and runs really well but that is getting less and less.
Any suggestions would be great even if the only make me smile as I am sad at the cars temperament
Ta >:(
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Shed some more light on the setup please Richard. Single/multi-point, make, age of system etc...
Kevin is very knowledgeable on these things and I'll be surprised if any of us come up with a solution he hasn't thought of but it's worth a go ;)
I assume that you've checked the obvious things like fuel filter/supply? I agree that the fact it runs OK on LPG makes a HT fault highly unlikely.
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Did he notice anything abnormal on the trims?
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Did he notice anything abnormal on the trim?
say it was a fuel problem not a hair cut one ::)
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would suggest a petrol supply issue i guess? cant think of anything Kevin would not have covered, but if the issue is now worse it ma y stand out a bit more on tech 2 now????? :-/
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Sorry I forgot to reply to the PM, Richard. ::)
My best guess was that the fuelling is way out on LPG, so block learning is adjusting so far that it won't then run on petrol.
I think, IIRC, we tried resetting the block learn and only running it on petrol and it was fine on petrol, but it was a while ago. :-/
Can't recall seeing any obvious problems with the MAF. Everything was fine except for the running.
I do remember that we switched between fuels on a run and the pre-cat Lambda was hard lean on one fuel and hard rich on the other.
To answer your questions, Richard, the MAF and Lambda sensors are used on both petrol and LPG.
Did we ever discover what LPG system it had on it? I would certainly like to get into the LPG system and see how it's tuned.
Kevin
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if its fine on gas, but nackered on petrol could one of the petrol injectors got clogged up from not being used? :-/
Cause normally any problems are magnified on gas, such as poor spark plugs :-/
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its a Pharos system (LPG) nobody seems to have the software.
The ecu for it looks exactly the same as the vogas unit but its got pharos on it.
The only guy thats ever looked at it has disapeared but I cannot believe I was just lucky and he had the software.. Maybe he made a generic adjustment ??
I believe he made a adjustment to the lpg mixture but as i said he's gone.
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I assume you checked the plugs/dis pack for water or oil ingress Richard?, solid plug connection on dis pack? Are the petrol injector plugs tightly fitted? Just seen a similar thread to yours (same system, same symptoms) on LPG Discussion Forum & it was a dis pack fault. HTH :y
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Thanks for the info about LPG forum.. Just had a look but cannot find it. What was its title or could you pop a link
Ta
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Sorry, don't know how to post HTML link :-[ If you PM me your email addy I can sent it that way as an attachment? ;)
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pm sent
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pm sent
Replied via e-mail (twice! :o) it wouldn.t send first time then went twice ;D HTH Regards, Phil. :y
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Thanks for that...
But my car runs a treat on LPG but rough on petrol which everybody says is round the wrong way for a ht problem as the lpg is much more fussy than petrol when it comes to spark etc.
???
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If its OK on petrol sometimes but bad other times then something is changing which causes the problem. Something like bad electrics (to the fuel pump ?), crap in the fuel line/tank/filter that shifts about, or an air leak that comes and goes (a pipe split/crack ?).
Trouble is if you reset the petrol ECU, you may not be able to retune the LPG side without the software and lead. A garage would concentrate on getting the petrol working right, but you might end up with an LPG system totally out of tune.
Ken
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Just to emphasise... This is highly unlikely to be a HT fault. Sounds to me like an issue in the petrol supply :-/
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Just to emphasise... This is highly unlikely to be a HT fault. Sounds to me like an issue in the petrol supply :-/
The fly in the ointment, and hopefully Richard can confirm my recollections here, is that we reset the block learn map and it then ran on petrol quite happily. I believe Richard ran it only on petrol for a while on my suggestion and it was fine.
On going back to running on LPG the petrol running then started to get worse again.
As I say, this is my recollection, and the reason that my suspicion is that the LPG system is over or under-fuelling.
Without access to the LPG ECU it's difficult to substantiate this theory.
Kevin
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I have exactly the same problem on mine, runs absolutely fine on lpg but misfires on petrol, not a severe misfire (more of a hesitation) but it is noticeable and the power is down too. It's also a problem when starting as well, especially from cold, will start ok (4 times out of 5) but the idle will quickly die down and will cut out if any throttle is applied. if it's left idling for a few minutes then it can be driven off and switched to gas asap.
The misfire does seem to clear itself eventually if I leave it switched to petrol long enough, once or twice it's done it within 15 mins or so but usually after a couple of days (50 miles or so?)
It doesn't do this everytime I run on gas though, more often than not it's after a single journey of 60+ plus miles, but sometimes it has been fine even after that.
Now this may be a big pointer to those of you who have an idea of what's going wrong... I can tell when it's going to happen because when running on gas the instantaneous mpg reading on the display will suddenly start to show unrealistic figures, virtually double what it normally would be reading (no way in this world will it start to do over 65 mpg at a steady 70mph!! ;D )
Have you noticed this on your's Richard?
So to my limited knowledge of the little black lpg boxes that are fooling the cars ecu, and confirmed by what has already been mentioned in this thread, this seems to me that yes it is running rich on lpg and the cars ecu is thinking it's leaning the mixture out, which again would give the symptoms I'm experiencing on petrol and the daft mpg figures displayed at times on gas. These figures become much more realistic when switched back to 'misfiring' petrol incidentally.
The lpg system has an AEB Pitagora emulator and an AEB OBDII and as I recently bought the car already converted I have no leads or software (nor experience of lpg) to be able to make any adjustments.
Does anyone know of a reliable person I could take it to in the Leigh/Wigan/Manchester area?
Sorry for woffling on.... :)
Thanks,
Kev
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Now this may be a big pointer to those of you who have an idea of what's going wrong... I can tell when it's going to happen because when running on gas the instantaneous mpg reading on the display will suddenly start to show unrealistic figures, virtually double what it normally would be reading (no way in this world will it start to do over 65 mpg at a steady 70mph!!
Hmm. That is indeed a pointer. Consumption is based on the main ECU's view of how much fuel is being injected. If the main ECU is having to cut back the injector duration due to a rich mixture caused by the LPG system it will show better fuel economy. It will also, in time, store this correction in the block learn map and the correction will be applied when running on petrol as well.
It all points to the fuelling on the LPG system being off, but since the majority of driving is on LPG it is the petrol running which suffers.
It's interesting that yours suddenly changes. Makes me wonder if there's an intermittent problem with the LPG system?
As to causes - could be that the LPG system just needs recalibrating or it could be that an LPG injector is sticking open or leaking. Could the the vapouriser not adequately controlling the vapour pressure or even the vapouriser diaphragm perished and leaking lpg down the vacuum reference port into the engine.
Getting hold of the software and cable required to diagnose the LPG controller is key, IMHO. Interesting that yours is an OBDII system. In theory that should interrogate the main ECU and watch the fuel trim, mapping itself automatically. I wonder if there's a quirk with the 2.2's ECU that makes that fail?
Kevin
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Ahhh... wonder if it's the vapouriser then... As far as I can make out the system has been in the car most of the car's life (tank is dated 2001) and although mileage is only an indicated 81k I have since found out that this is a teensy weensy bit wrong... it had done 170k in 2008 according to online MOT history!!! Perils of a private sale I suppose ::) And I have no service history or reciepts at all so the vapouriser may indeed be way overdue an overhaul. Only identification I can see on it is Autogas.
Can't see any id on injectors either, other than they are blue.
When I bought the car in April I was told the lpg wasn't working, he said the tank was full (as substantiated by the 4 green leds on the switch) but engine just dies when it is switched to gas. (Was running fine on petrol I hasten to add and I thought I was buying an 80k mile car... haha)
So I got it home, learned what I could about lpg systems and set about checking basics... Took plastic cover off tank and saw another gauge... yep, you guessed... empty... ;D A fivers worth of gas added and it was running on gas... although with a bad misfire... one new set of plugs later and it was fine...
Switch still constantly shows 4 green leds though but I can live with that.. ;D
Other than aircon not working (climate control is all functioning) and drivers seat not getting warm all is ok despite the mega-miles.... (oh, and headlight adjusters)
Time to stop woffling again.... hehe
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Check the petrol/fuel injector wiring and their clips/plugs. Happened a couple of times to me - injector wiring had a split or plugs not seated correctly. Good luck... :y
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Checked those and all seem fine, well, as much as I can, tricky to get to with lpg stuff there as well. :)
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I've got to go to work in 5 minutes but will try and put some thoughts together and post either tonight or tomorrow.
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Right,
Kev B. Is your system a single point or multi-point kit. I know it sounds like a silly question with the OBD II part but it's rare to get seperate emulators on a multi-point setup, they're normally integrated with the ECU ;)
Sounds like you also need to follow the advice Kevin Wood has given... You need a lead and the software to interrogate the LPG ECU. Sounds like it's not setup correctly any more :y
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Hi. Yeah it's a multipoint, has got 4 little blue injector things each with a pipe going to the inlet manifold.
The Pitagora box is mounted on the offside suspension turret and the OBDII is in the triangular box near the battery.
So do both these do the same job? Please correct me if I'm wrong (I'm still in the very early days of trying to understand lpg systems ::) ) but I'd come to the conclusion that the Pitagora emulator was fooling the cars ecu into thinking it's still running on petrol and the OBDII was applying the cars ecu info and adjustments to the lpg system.... As I said please put me right if what I've just said is pure babble.
These are the only additional boxes I've been able to find on the car, I presume there's no other ecu tucked away anywhere as I thought it piggy-backed off the cars original one.
So now on the lookout for an AEB interface lead and software, then I need to work out what it's telling me.... ;D
Jeez.... these litle black boxes... oh to go back to the days of the lovely simple Essex V6's... (Yep, Capri freak from the age of 17... hahaha) :D
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Petrol cut-off not working possibly???
Edit...
Ignore that its the petrol side that's not working right!!! Other way round - is it possible lpg side is not cutting off?
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Kev, your understanding is correct. Now days the 2 are combined :y
Could be a LPG solenoid fault (as rikki says) but they generally fail shut, not open ;)