Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: chrisgixer on 28 March 2015, 21:49:35
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At a roundabout. Trying to judge the traffic to pull out, hard on the throttle then off again after a momment of doubt, brake, then back hard on the throttle....
....nothing.... .....still nothi.... Ah finally away we go.
No engine revs, so not a slipping box, on gas but not quite fully warm. About 70c on the gauge.
So just to recap, happened at about the pace you would read it the text;
Full throttle Off throttle brake full throttle.... .....no response.... no response.... Gently power comes in/revs rise.
Did I confuse it or is there an issue? Iirc they can get fuddled momentarily.
Shit driving really i should of either just gone or waited. But didn't give on coming traffic a problem. Although if it had waited any longer.....
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Haven't got any rubbish tyres fitted per chance, maybe they were spinning round and smoking like a good un, but seeing as your busy looking at the oncoming traffic you never saw the TC Light flashing. :-\ :)
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Haven't got any rubbish tyres fitted per chance, maybe they were spinning round and smoking like a good un, but seeing as your busy looking at the oncoming traffic you never saw the TC Light flashing. :-\ :)
Engine revs didn't respond.
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Sounds like a momentary snafu... If you press the throttle with your foot on the brake on a diesel, the engine literally chokes itself... Wonder if this caused a similar effect, disrupting the plenum vacuum :-\
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Just the once? Or has it happened before?
As always with LPG cars, first step is to see if it does it on petrol - but if its a one off, that will be impossible.
I'm sure we've seen similar with 3.2s and LPG, where on-off-on throttle gives a lag (and it happens on petrol, but LPG amplifies the problem), though normally at higher RPM?
Lastly, are the trims roughly where they should be? Had it been idling for ages (enough to whack the LTFTs out of kilter, so when booted, it was hestitant). Might be worth, on LPG, monitoring LTFTs over 30 mins of idling.
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No tick over. Jump in, start, drive off. Then probably two minutes of 30-40 limits, quick blast up to 70, then stop for the round about. Car in front pulls away, my turn, then the problem. Wasn't stationary for more than two seconds.
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Trims where within +/- 2 on both banks last I looked. Will check.
Will repeat the scenario as well, and see what happens.
Not aware of Asking the car to do that before tbh.
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No tick over. Jump in, start, drive off. Then probably two minutes of 30-40 limits, quick blast up to 70, then stop for the round about. Car in front pulls away, my turn, then the problem. Wasn't stationary for more than two seconds.
Before stopping, had there been any "unusual" engine speed/load (ie, idle) for any great length of time? As the trims would take a good few minutes to sort their life out if were way off.
Personally, I think its related to that on-off-on lag that we've seen before on the DBW V6
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Trims where within +/- 2 on both banks last I looked. Will check.
Will repeat the scenario as well, and see what happens.
Not aware of Asking the car to do that before tbh.
Trouble is, its what the trims were at the time
Long periods of "unusual" rpm/load can knock LPG trims way off, esp on the OBDII compliant cars.
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Absolutely nothing unusual about the journey. It was my morning commute. No tick over at all. Not even cold. Not frosty so didn't need to clean the screen.
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Absolutely nothing unusual about the journey. It was my morning commute. No tick over at all. Not even cold. Not frosty so didn't need to clean the screen.
What about the previous journey?
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Absolutely nothing unusual about the journey. It was my morning commute. No tick over at all. Not even cold. Not frosty so didn't need to clean the screen.
What about the previous journey?
commute home was uneventful. No unusual traffic. Even had a bit of a play.
Good point though. :y
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As you say I think/guess it's related to the lag, but what's unusual to my experience of that is, apart from bending stationary, is the very gentle way it eventually pulled away. Bit like it was in third/snow mode, very slow and deliberate, except it was in first as you'd expect.
It certainly wasn't trying to replicate the pedal position at full throttle as I was asking for. I was completely over ridden. ;D
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What state are the throttle bodies in? If they are a bit gunky, and the throttle was slammed shut, then immediately reopened, if the servos struggled initially?
(though I don't think so, as much as I'd like to state cable throttles are superior :P)
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What state are the throttle bodies in? If they are a bit gunky, and the throttle was slammed shut, then immediately reopened, if the servos struggled initially?
(though I don't think so, as much as I'd like to state cable throttles are superior :P)
Nothing unusual going by the last time I had the bag pipes off. But probably haven't been cleaned since the last time the cam covers and breathers where done/cleaned.
I do wonder quite how gunked up a Dbw throttle needs to be before the motor can't shift it. I'd suspect an electrical fault first I think.
Suspsion is something in the software found the drivers inputs ...inplausible? Then decided to do the nearest sensible thing instead ;D
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Although, thinking further, there was a thump. But I can't remember if that was the trench that had been badly filled in running across the road (there's road works on that roundabout as they are replacing the traffic lights, hence I coulnt see if the car was turning off at the previous junction due to all the Orange barriers in the way) or due to the drive train. My first though was gear box banging into gear, but it couldn't of been as the revs refused to respond.
....unless the dif locked up. :-\ it's an LSD
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I have had this happen to me on LPG. Seemed to disappear after a LPG filter change.
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Oh I've had loss of power, caused by fuel trims wondering off. Car just spluttered and bogged.
But this is differant. There was NO response from the engine. None of the spluttering, rough running, miss fires as the engine TRIED to respond but couldn't that you might suspect from poor set up.
I may as well of had my foot off the accelerator altogether.
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Reading this one with interest, Chris. My car suffers from hesitation still in my opinion even though I've replaced a faulty front vacuum box. Obviously your problem could be LPG related and I sadly know nothing about the intricacies of that.
I've done a bunch of looking for vacuum leak things, replaced a few things, to no avail. Some on the net state that the 2.5 has a noticeable dead spot but DTM confirmed that with everything working properly there should be no flat spots at all. So God knows where to take it next.
But I appreciate that this sounds like a different problem.... not a hesitation, simply no power AT ALL for the first couple of seconds. Oddness!
Anyway, to the point of my response have you hada butchers for vac leaks?
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Sounds like a momentary snafu... If you press the throttle with your foot on the brake on a diesel, the engine literally chokes itself... Wonder if this caused a similar effect, disrupting the plenum vacuum :-\
I don't know about diesel engines (I think they use a vac pump in the alternator) but on a petrol engine the brake servo has an inbuilt vacuum reservoir that is good for about 3 or 4 applications of the brakes.
Stamp on the brakes 5 times in quick succession (with the engine idling) and the brake servo will dump enough air into the inlet manifold to make the engine falter. (Steady pressure on the brake pedal won't upset things because the servo doesn't let air in until you take your foot off the brake)
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Oh I've had loss of power, caused by fuel trims wondering off. Car just spluttered and bogged.
But this is differant. There was NO response from the engine. None of the spluttering, rough running, miss fires as the engine TRIED to respond but couldn't that you might suspect from poor set up.
I may as well of had my foot off the accelerator altogether.
Exactly, no response at all, like it had died. Not happened since the LPG service and filter change.
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Reading this one with interest, Chris. My car suffers from hesitation still in my opinion even though I've replaced a faulty front vacuum box. Obviously your problem could be LPG related and I sadly know nothing about the intricacies of that.
I've done a bunch of looking for vacuum leak things, replaced a few things, to no avail. Some on the net state that the 2.5 has a noticeable dead spot but DTM confirmed that with everything working properly there should be no flat spots at all. So God knows where to take it next.
But I appreciate that this sounds like a different problem.... not a hesitation, simply no power AT ALL for the first couple of seconds. Oddness!
Anyway, to the point of my response have you hada butchers for vac leaks?
Yours has a throttle cable, so direct connection from your right foot to the throttle...
With DBW cars, you can do what ever you want to the throttle pedal, and 9999 times out of 10000, it will react accordingly, but every so often the computer simply says No... question is why :y
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Oh I've had loss of power, caused by fuel trims wondering off. Car just spluttered and bogged.
But this is differant. There was NO response from the engine. None of the spluttering, rough running, miss fires as the engine TRIED to respond but couldn't that you might suspect from poor set up.
I may as well of had my foot off the accelerator altogether.
Exactly, no response at all, like it had died. Not happened since the LPG service and filter change.
Drive it on petrol for a bit to see if it happens again so you can rule out LPG issues? :-\