Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Paulus on 03 January 2008, 12:48:16
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This morning, I developed a misfire. It was fins for my initial 40 mile trip, then after standing for an hour, I started it up and it was missing. There was also a strong exhaust smell through the vents. Could a leaky exhaust cause a misfire? I also noticed that there was a tapping noise from the engine. Could this be unburnt fuel doing strange things?
I've had a look at HT leads and a general look round this lunch time, but I can't see anything amiss. It started ok, but after about 1/2 mile, the misfire came back.
I have recently put new sparkies in and done the cambelt, but I have done 500 miles since then.
Any ideas? I've only just put it back on the road after 3 months on the drive :(.
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A few years ago, on my previous Omega, I changed the plugs and used Bosch replacements. Car acquired a misfire after a couple of weeks and when I found up a local mechanic his first question was "Did you use Bosch plugs? If so, take 'em out and use NGKs". I did and the problem went away. :y
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They are GM genuine parts.
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In view of the tapping and smell would it not be wise to check the cambelt job. Did you replace pulleys and tensioner? Slipped tooth? Don't take any chances!
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In view of the tapping and smell would it not be wise to check the cambelt job. Did you replace pulleys and tensioner? Slipped tooth? Don't take any chances!
That's what I was thinking... :(
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Check the obvious first.
Fault codes check? (could be first signs of crank sensor)
Are the plug leads seated correctly at both ends? Not soaked in oil?
Connectors seated fine?
Does it run completely fine when cold?
Have you recently changed the cam cover gaskets?
Leads that sit in oil will often start to fail soon after the gaskets are sorted. Check the resistance of the leads. Should be between 2k-10k ohm as I recall.
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I have recently changed the cam cover gaskets...I have also fitted a new crank sensor at the same time. the sparkies that I can currently get at have no oil on them and everything seems tickity-boo.
The rest will have to wait till the weekend...back to the 306 TD >:(
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Spark plugs torqued down correctly?
One worked loose?
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Could well be...as it didn't misfire when cold, I am hoping that it isn't the cambelt slipping.
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I've just been thinking...when I say misfire, what I really mean to say is that one of the cylinders isn't firing whatsoever.
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The symptoms do not point to cambelt slipped, that will make the car feel wrong whether it is warm or cold.
Do check the spark plug torques (use a torque wrench, a stripped thread is not fun to sort as Mark will testify to!)
If not, it is plug leads first then DIS pack as it sounds ignition related.
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The symptoms do not point to cambelt slipped, that will make the car feel wrong whether it is warm or cold.
Do check the spark plug torques (use a torque wrench, a stripped thread is not fun to sort as Mark will testify to!)
If not, it is plug leads first then DIS pack as it sounds ignition related.
I fully agree with Dave, but would also add that if you don't find a loose plug, it would be worth a quick compression test before spending out on leads / DIS
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Check the leads are seated at the DIS end too - I found its very easy to dislodge them when refitting the cam cover. If they are arcing that could be the noise you are hearing..
It could also be that the leads have dried out now and are starting to break down when hot.
I assume there is no engine management light on?
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I've had a quick check tonight...I can't see any arking in the dark. I also checked the N/S bank of plugs as they are easily accessible. All tested ok with an inline spark tester.
At tickover, there is no misfire, but the slightest load, ie when in D, it misses.
I'll have to wait till the weekend to give it a thorough check now. >:(
Thanks for the advice guys. :y
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A few years ago, on my previous Omega, I changed the plugs and used Bosch replacements. Car acquired a misfire after a couple of weeks and when I found up a local mechanic his first question was "Did you use Bosch plugs? If so, take 'em out and use NGKs". I did and the problem went away. :y
strange, OE plugs are bosch items, never had a problem with them but have had with NGK
Andy
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One thing I always us on cars is OE ignition parts. They spend millions getting it right in the development stage, so why mess?
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Update...
I haven't had much time to play, but this weekend I had a quick look.
I started it up no problem, but the engine sounded a bit "mechanical". I took it for a quick drive and within 30 seconds it was misfiring.
When I popped the bonnet up, the mechanical noise seemed to be coming from the N/S back of the engine.
Does this sound like something obvious to you knowledgeable people?
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No suggestions?
Mechanical noise...misfire........anyone? :-/
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Hi,
Been looking through threads and your problem sounds just like mine (moorej91), my 2.0ltr auto starts first time and runs fine fro about 5 mins then runs really lumpy with no power. Tried loads of things. With no other option I am going to Vauxhall dealer on thursday for diagnostic check. Will let you know the outcome in case it will help you sort yours out.
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Great stuff. I have checked my Cam alignment...all is well. I have got new sparkies to put in and the leads are on order.
Fingers crossed for the weekend.
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[size=48]SUCCESS[/size]
New plugs and leads...sorted!!!!