Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Omena on 25 February 2016, 15:46:41
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Not allways.
Seems appeared like this: i start cold engine in morning, no problem. I drive 60miles and go work. After 2-4hours i start and idle goes about 1500 but then shifts 1400-1300 and is rough about 2-4seconds and then is stable 1300-1200 and then drops normal and works fine.
I get "My Naff Code Reader" back later so i just think ask for now what can cause that? Warm engine is okay.
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Now it does with cold engine : revs 2000 and then drops 1300 and swings little time and then drops normal.
And warm engine engine light appeared and code p0420.
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Are you loosing coolant?
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No. Im watching coolant and oil every week because i drive about 400-600miles week.
Dont you say that those are first symptoms for head gasket? :-X
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Does it improve with the MAF sensor unplugged :-\
If yes, then you need a new MAF sensor... only buy genuine or Bosch :y
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I try that.
Intake temp is ok and all values when i checked with "My Naff Code Reader". That cold start "issue" is gettin worser every time but its very fast so its not big problem yet.
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With maf off, it was pretty same but stumbles second just after start.
Feels like little misfire that little roughness in cold.
Maf voltage is good also. No codes
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Check the spark plugs and see what colour they are.
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Plugs were fine. No marks for oil or coolant deposit and all four were identical.
Trhottlebody was very dirty and valvecover to throttlebody hose was cutted off.
When i get that little hole open in throttlebody then lets have a look. Does someone know what size that hole is? Wire or needle wont go thru it seems to be very dirty.
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I got the hole open. Seems fine now but i try tomorrow over night.
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How is the egr? Clean it and try again
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I check that. If its bad, can i block / disconnected it or does engine need that /fault codes?
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Btw cold idle roughness is gone!
Is that normal when you start on freezing temperatures, idle revs about 2000 rpm then goes 1400 like normal?
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Btw cold idle roughness is gone!
Is that normal when you start on freezing temperatures, idle revs about 2000 rpm then goes 1400 like normal?
I suspect two things, mine 2.0 4 cylinder had the same problem.
1) Idle Air Control Valve needs cleaning
2) significant vaccum leak
good luck
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Ill do those checks too
Cold engine no problem but now aftee 3h stand it was little roughness again but revs was 1500 max not 2000. But idle is not that rough than before cleaning.
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2.2 doesnt have ICV.
If i block egr and take socket off, will fault code do changes to mixture etc or is it just a code?
Or will metal plate under egr work with egr socket on?
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2.2 doesnt have ICV.
my apologies.
regarding blocking egr valve I think there is How To in the Maintenance area on the forum
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I found only egr cleaning guide.
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Hm... look closer. I know there is one because I used it to block the egr on my car.
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But to be honest, I doubt the egr has to do with rough Idle. Did you check for vacuum leaks?
Is it an automatic? Does the rev rise when you put it in neutral while moving?
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Manual. Vacuum hoses are new now. No effect.
-10 celcius in the morning and runs fine again. But after 2hour it stumbles again. Whole engine vibrates and then it goes lighter and then disappears.
Very difficult to say is it misfire or another hesitation.
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Does the check engine light come on?
Did you try the pedal test to see if there are any errors stored?
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Pedal test ok. No trouble codes or check engine.
Today i first time tried press pedal immediately after startup. It dropped faster idle to normal but that roughness continued.
So seems to be like thay roughness is under 1500rpm and it lasts about 5-15seconds no matter rpm range and then disappears. When i also tried 2000 rpm after startup it was fine.
And this is again with engine started before and cooled about 2-4hours.
Today was - 5 and it standed about 4h before next start so its very close to full cold engine.
But first cold start in morning no problem again.
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What about fuel consumption? Has it become worse?
There is not much I can suggest to fix it rather than spark plug wires (leads), see if there is any vacuum leak and of course, OBD 2/Tech 2 code reader.
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Fuel consumption has been very good all the time. About 7,7 liters per 100km (60miles).
I have "My Naff Code Reader" but it wont find anything and all sensor voltages etc are good.
That bothers me: why semi or allmost cold engine only? Not warm or full cold.
Maybe i have to buy new plugs. Coil i dont wanna buy yet, nobody has same car so hard to try that without new.
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Spark plug wires/leads along with spark plugs also should be replaced. If not possible then inspect them for cracks and/or change of colour on the silicone insulator.
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No 1 coilpack rubber boot? (that one where plug comes inside) has hole about size of little peanut. Its bottom side so i dont know can it cause that symptoms.
Hard to explain...
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But it haa been that all the time.
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Couple starts idle was okay.
Today it gived new code: p0170 :-[
What is most common sympton for that? I cleared it and it disappeared at least.
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Fuel trim error? Lambda sensor maybe? Try get a multimeter on it, see if it behaves as it should.
As for plugs/wires, seems unlikely as it would be most noticeable when hot. I had this exact issue on my kit car. In traffic/low speed was worst. Also, I think looking into that would be an expensive route, think the 2.2 has a DI pack. Rather than individual coil packs :-\
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DI?
2.2 has a single coil pack :y
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Ah, sorry, Saab speak creeping back again. :-[
The single black plastic thingy running between the cam covers is known as a DI (Direct ignition as opposed to Direct Injection) Cassette/Pack on GM era saabs.
Is it possible to change single coils on the 2.2 ones or are they "potted" together as they are on Saabs?
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Single unit, common to several four cylinder Vauxhalls ;)
The saab units are a stupid shape to save the ignomy of fitting a cover plate ::)
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Single unit, common to several four cylinder Vauxhalls ;)
Common and cheap. Which is what service parts should be.
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That is good news. The Saab ones were in the region of £200. Or £50 if you were satisfied with a lifespan of about 1000 miles.
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Today was - 8 Celsius. Cold start idle revved in 3000rpm and then dropped.
When i bought car cold idle was max 1500rpm no matter how cold was.
Something is now went wrong. No fault codes.
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vacuum leak
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vacuum leak
Totally agree, air getting in system after the MAF
when tickover is rough spray brake/carb cleaner 'lightly' around the small vac pipes, brake servo, HBV, throttle body, pipes from cam cover to TBody. and EGR (rear of head). If tickover smooths then find the leak. Two small vac pipes go through bulkhead to cabin heater control, could be leaking behind dash, temporarily clamp them to test.
This could also be Lamba related eg not sensing correctly or heaters not working correctly, bit harder to diagnose without swopping for known good
HTH
Phil
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It is either what mr Phil said or just stick your head under the bonnet and listen carefully. You should be able to hear hissing sound.
By the way, I didn't know that hbv could also be leaky of vacuum.