Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: mega3.0v6 on 28 May 2008, 15:20:25
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Had car plugged into a snap on machine scrolling down the mechanic notice my car was running LEAN/RICH could this be my problem i changed fuel filter yesterday aswell. As i looked underneath and looked like it had the original filter on it as it was a GM one and was rusty so any ideas Please.
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I'm confused....
Was it lean or was it rich? Cannot see how it can be both at the same time.... :-/
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Lean or Rich would have been the live data indication from the Lambda sensors. They are supposed to cycle between lean and rich a couple of times per second. The operator clearly didn't know what he was doing, IMO. Sounds perfectly normal to me, unless they weren't cycling. :-/
What is the problem you are having?
Were there any trouble codes stored int he ECU?
Kevin
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The problem i have is that when cold driving the car till it starts to get warm is fine. BUT when it is warm on the 90 degree line between 1k to 2k revs it hesitates when revs get passed 2k all is fine. Had it on tech2 and a snap on machine no fault codes stored or found i have changed plug and leads also oil oil filter (i know nothing to do with it) fuel filter. The vauxhall guy i had look at it quickly said the eml has to be on for the tech2 to find anything. I got a feeling crankshaft sensor maybe when the revs are low that is when it is at fault. but surely eml should come on if there is a fault i have run out of ideas and near enough skint to think of anything else it can be. The car has done 76k on 98 S 3000cc.
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Is the ECU getting a sensible reading from the coolant temperature sensor?
It uses a different sensor to the panel display, so a correct gauge reading could be misleading.
If it thinks your engine is still cold it supply excess fuel, that won't help the way it runs.
One of the live data displays is coolant temperature, at least on the Opelscan.
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Could this go if the oil cooler had gone. How can i find out if that is working or not working properly.
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Simplest way is to plug in a diagnostic device that will display temperature and voltage from that sensor.
You could measure its resistance hot and cold, I don't know what values to expect, at least they should be different.
Oily residue might have contaminated it, anyone seen that?
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Is there a switch on the gearbox (manual) as i heard a load click when changing gear and when it starts to do the jurking i dipped the clutch and it revved up fine.
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The problem i have is that when cold driving the car till it starts to get warm is fine. BUT when it is warm on the 90 degree line between 1k to 2k revs it hesitates when revs get passed 2k all is fine. Had it on tech2 and a snap on machine no fault codes stored or found i have changed plug and leads also oil oil filter (i know nothing to do with it) fuel filter. The vauxhall guy i had look at it quickly said the eml has to be on for the tech2 to find anything. I got a feeling crankshaft sensor maybe when the revs are low that is when it is at fault. but surely eml should come on if there is a fault i have run out of ideas and near enough skint to think of anything else it can be. The car has done 76k on 98 S 3000cc.
He clearly doesn't know how to get the most from his diagnostic equipment! ::)
Some faults don't light the EML but are stored anyway. In addition, problems like this can be diagnosed by watching how the live data behaves when running, if you have the knowledge to interpret it.
I say it could be a crank sensor (which would normally generate a code but NOT light the engine light), temperature sensor, as mentioned or a problem with a lambda sensor, as these are normally disabled at low coolant temperatures.
A look for fault codes, and the live data, would confirm the problem, I'm sure. Shame the guy with the Tech 2 was not a bit more switched-on. You can spend thousands on diagnotic tools, but if the user is a muppet.... >:(
Kevin
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LOL i agree. Would doing a paper clip test tell me anything.
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it would give you any stored fault codes,crank sensor would be code 19.
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It won't help you with temperature sensors.
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Where will i find the temp sensor not the one for the dash gauge but for the ecu is it next to the dash sensor one. :-/
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They are both screwed into the coolant bridge, if I remember, one has more terminals, but I can't remember which is which.
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The one with just a single terminal is for the gauge.
Kevin
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Today i changed the engine coolant sensor was ok for 10 miles then it all started again. But i have a little feeling the thermostat is clogged up or stuck as the temp is getting high. I was in the misses omega sitting in traffic and hers goes just over the 90 line where as mine goes near 100 so im thinking that the water is not getting round the engine properly may be wrong but could this happen. When i changed the sensor i thought woooooo hoooooo fixed then it started again NOT HAPPY. Any thoughts on this being the case.
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btt
::)
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My thoughts are it could be a crank sensor playing up when hot, possibly an ignition problem (coil pack?), again playing up when hot or possibly a Lambda sensor. I would paperclip it and see if there are any new codes. :-/
Kevin
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I have done a P/C test today with just 12 coming up.
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I might be inclined to suggest an ignition problem in that case. First things first. Check the plug wells are clear of water and then the plugs, leads and DIS pack.
Getting one of our Tech 2 guys to take a look at the live data would be worthwhile, though, just in case something unusual is playing up.
Kevin
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I have checked for oil and water but all pots are dry. When i changed the sensor all was fine for 10 miles or maybe abit more then started again and my temperature seems to be really high compared to my wifes V6 mega. The thing that is really confusing me is that when cold all is fine till it hits the 90 degree mark on temp gauge after that its sort of a misfire but there is not popping seems as though it is flooding itself then when revs are right over the 2k runs fine again. The problem seems at the bottom of the range and when i had tech2 and the snap on machine plugged into it no faults were found and firing on all 6. Im going to run it up to my mates garage tomorrow and take him for a spin to see if he can diagnose prob. With a machine plugged in whilst driving.