Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Radar on 17 October 2012, 20:14:40
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Following on from tech2 sess. at the oxford meet it threw up a code 19 so changed the crank sensor today (genuine gm from stealer) and drove for 30 minutes and the stuttering that i had whilst driving to the meet at the weekend did not come back.
But she is still a bit lumpy on idle and wondered if anyone had any ideas why? It started to absolutely tip it down so i couldn't get round to cleaning icv, egr and maf? Is there anything else worth looking at?
Also after 30 minutes drive i let her idle for a bit and could hear a tinny ticking coming from the rear / mid exhaust section but not sure (i.e. engine was warm).
Lastly there is a bracket which connects to the bulkhead from the a/c pipe with a 8mm torx screw - i think i have buggered the thread as it no longer holds tight - i dont have a die set and wondered if i can secure this another way?
Thanks
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Remind me, what work did we do on it..?
Thinking coil PAC... Perhaps..?
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I'd start with EGR. If it's sticking open even a tiny amount, the deep vacuum at idle will pull through a load of exhaust gas that the ECU is unaware of, causing mixture mayhem.
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Clean the ICV, as discussed
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Ah, lumpy at idle, or idle is varying....?
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Will clean the icv and egr and report back Thanks TB / Abiton:y (is it worth doing maf?)
Chris - I watched whilst you did cam cover gaskets on passenger side and put in new ht leads (Last christmas) :y.
I changed spark plugs, dispack and crank sensor in the last month.
P.S. I would say it is idle is varying.
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Don't touch MAF, likely to do more damage than good
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Dont clean the MAF.Its too fragile. ;)
great minds.........
fools seldom......... :D
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Ok as said then.
But don't clean maf. ;)
Unless someone knows what to clean it with without killing it...?
I don't think maf is suspect though is it...?
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Thankyou.
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Lastly there is a bracket which connects to the bulkhead from the a/c pipe with a 8mm torx screw - i think i have buggered the thread as it no longer holds tight - i dont have a die set and wondered if i can secure this another way?
Thanks
Loctite a short length of appropriate studding(probably M5) into the thread and use a nut.
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Cheers Nick :y
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Cleaned the icv and egr valve and took for a spin. The idle holds steady for a bit then dips and engine judders and the sequence repeats itself.
Is the inside of the egr valve supposed to be silver? like the icv valve. I cleaned with wickes paint stripper and a toothbrush then let soak for 3 hours and some carbon did come out but the insides were brown (but no deposits if you know what i mean?). Should i have left it to soak for longer.
Any pointers appreciated :y
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Carb cleaner is usually fine.
Did you lubricate it? 3in1 or similar light oil. :)
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I cleaned the icv with carb cleaner then lightly oiled.
EGR was cleaned with paint stripper, then carb cleaner but no oiling after.
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Did you mean oil the egr?
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Sorry, I was referring to icv only. Clean with carb cleaner, light lube, re fit. :)
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Thanks Chris - i did the icv as you stated and actually did the egr valve again and lightly oiled it - she is still stuttery on idle :-\
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Assuming TB checked it for air leaks, sounds like dicky icv. Ime, it might be worth repeatedly cleaning, lubing icv, as my old 2.5 icv responded well eventually. Or fit used?
See what others say. :)
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Might be worth blanking the EGR.
Didn't get time to measure the MAF, as OP was already getting his knackers chewed off for being late to a birthday party ;D
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Thanks guys - i will clean icv a few times over the next few days.
Then i will blank egr as per link below:
http://www.omegaowners.com/forum/index.php?topic=20307.msg306008#msg306008 (http://www.omegaowners.com/forum/index.php?topic=20307.msg306008#msg306008)
This could be a good addition to the maintenance guides if admins. see fit?
P.S. I got back from Cuttleslowe in record time - i had a 911 and an aston martin pull into the 2nd lane to let me past!
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Update:
I have blanked off egr and cleaned icv several times (over the past week) The idle is ok for a bit, then the revs drop and she shudders and this process repeats itself.
Also noticed that when i move from park to d sometimes the 1 light flashes.
Any pointers appreciated :y
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If you haven't already done so, might be worth going round with a can of carb cleaner searching for air leaks.
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Paper clip it for codes. :)
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Cheers guys - will spray carb cleaner around and paper clip again - (for info. i did paper clip after the oxford meet and no codes were present)
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Paperclipped and just came up with 12 and 31. No signs of leaks when spraying carb cleaner with engine running.
I cleaned the breathers as per guide including vent housing - the small pipe to the housing was clear but just put a pin in there to clean it and a squirt of carb cleaner, the larger one i could not get off so i squirted a small amount of carb cleaner into left side big pipe (i blew down it first and seemed clear) and the other large breather pipe.
On the breather box the "pipe" that leads to the two small holes on the box had quite a bit of carbon come out - this was cleaned to within an inch of its' life!
Then did an oil change and to get the oil warm let it run for a couple of minutes - it was popping / stuttering all over the place. Thought any gunk would come out with the old oil but even after the change it is still popping (though not as much as before).
I double checked everything was put back together correctly and i believe it has been. I couldn't see where the other small breather pipe connects to - it looks secure but could not follow its' path - where does it go?
I hope i haven't messed it up by squirting carb cleaner down the big 2 breather pipes but the engine is popping like its bonfire night :P
Any help / pointers much appreciated :y
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Popping is a misfire. No?
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I woulod say no. It sounds like when you squirt carb cleaner and it pops - If you know what i mean?
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More like a backfire
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Took the plenum off and it looked like one of the o-rings was not seated properly. Put the plenum back on and no more popping / backfiring :y
The idle is still stuttery though :(
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Car still stuttery on idle - the egr blanking plate made no diff. when on for 2 weeks so i took it off since it seemed to use more fuel. This is not a major issue but is the icv for 2.5 ltr petrol common to other engine sizes? - might try a cheap secondhand one as a process of elimination and it will make it easier to find if it is common to more than 1 engine size .
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Don't touch MAF, likely to do more damage than good
Don't touch MAF, likely to do more damage than good
agreed :y It may be worth disconnecting multi plug from maf to see if it helps :-\
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Change your plug leads mate mine was like that-cheap leads were breaking down and arcing-took me some time but touched the while engine running wallop-nice shock to the system :D