Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: nixoro on 25 October 2007, 19:07:56
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I still have a shaky start when the engine is cold.
Have so far cleaned the throttle body the IACV changed the oil separator, cleaned the egr valve changed the Vac pipe which runs from the EGR to throttle body
Cleaned all the breather pipes including the small drilling in the side beneath the throttle body.
Now thinking maybe another fuel filter and maybe replace the air filter or even the leads.
**Edit** forgot to mention its had a full coolant change and new thermostat recently fitted, also a new rad last year.
Running out of ideas now.
in the passed year its had new plugs, the rocker cover has been resealed.
Can anyone suggest anything else to look at.
All help will be much appreciated.
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Before starting in the morning Roy, give it all a good WD40. If that improves it a lot, start thinking about leads.
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Before starting in the morning Roy, give it all a good WD40. If that improves it a lot, start thinking about leads.
Cheers for the input i shall give this a go Saturday morning :y
I might just try some new Bosch leads for piece of mind think they are about £30 from Halfords
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Take one of your old leads with you to compare, I think the leads in Halfrauds have the wrong boots on them, they connect OK but are too small to seal to the head on the Ecotec....meant for the 8 valve???
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Two remote possibilities come to mind.
1) If the coolant temperature sensor is duff, the wrong fuel/air mixture will be supplied by the ECU.
2) If one of the plugs is not quite fully home, you can get less compression until the block gets hot, expands, and "reseals" the plug.
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Either that or it's a bit of piston slap. Do a compression test and compare the values, I'll be especially interested in Pot 1 [smiley=evil.gif]
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Take one of your old leads with you to compare, I think the leads in Halfrauds have the wrong boots on them, they connect OK but are too small to seal to the head on the Ecotec....meant for the 8 valve???
I had a look at a set yesterday and they didn't look to good.
I spoke with autovaux a few weeks back and they say they can supply me a set for £30 i'd guess they are vx or similar think I may go down this route.
Have noticed since doing the thermostat change the windscreen mist across the bottom could a pollen / air filter be causing my troubles?
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Two remote possibilities come to mind.
1) If the coolant temperature sensor is duff, the wrong fuel/air mixture will be supplied by the ECU.
2) If one of the plugs is not quite fully home, you can get less compression until the block gets hot, expands, and "reseals" the plug.
Option 1 not sure about this where abouts is the temperature sensor on the 2.0 16v so I could check it..
Option 2 might be a possibility but when I changed the plugs they were torqued down so might take a second look and go with new plugs aswell.
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Either that or it's a bit of piston slap. Do a compression test and compare the values, I'll be especially interested in Pot 1 [smiley=evil.gif]
How good are these testers and how do you do the test
Read somewhere you do it with all the plugs removed is this right.
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It will be one of your sensors, injected engines normally start on the button if they dont then that is your starting point. So before using a sledge hammer to crack your nut check them. You would notice your compression just on performance of the engine. Everything done to date has been mechanical, you do have an electrical system also just as prone.
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Possible the car has had a new Cam shaft sensor and new MAF sensor in the passed year or so.
Currently I have not had any EML lights appear also did the paper clip test earlier and no codes showed shall be doing this again at some point this week when I am not in a rush for piece of mind.
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Either that or it's a bit of piston slap. Do a compression test and compare the values, I'll be especially interested in Pot 1 [smiley=evil.gif]
Exactly..
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Thing is imo performance would drop and it seems to run fine plenty acceleration when needed :y
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either the compressions are not equal (still my idea) or crankshaft balance (rare I never see)
edit :*********
or sparking is not equal on all cylinders
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either the compressions are not equal (still my idea) or crankshaft balance (rare I never see)
edit :*********
or sparking is not equal on all cylinders
Only happens on start up fine the rest of the time :y
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another explanation may be ..somewhere else any leak into engine after it become hot its gone..
sorry ideas finished (bitti) :)
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"Only happens on start up fine the rest of the time :y"
Would it be fair to say that on a normal engine when starting from cold you would use the choke :question
It is exactly the same with an injected engine, with the exception that it is done for you electronically.
So what is being sensed on cold start : Temp : airflow : accelerator position :
The ecu will then set your mixture to suit the conditions being sensed. :y
Check the connections always a good place to start, remove the plugs and ensure that they are clean, sometimes just removing and replacing literally cleans the contacts. If you have a meter it would make it even easier, another check is to ensure the wiring to the plugs are ok, they sometimes workharden and snap. Taking your time is always the best way be confident because it will not catch you out again.
I am purposely not including all the other checks that are being made by the ecu (avoids silly comments)
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Try a different brand of fuel - mine is "odd" when cold. It starts fine but doesn't feel right. I've just switched from BP to Shell and it's much better, even removing the inital lag when I set off.
Oh, and it won't cost anything either. Worth a try :y
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I have a similar problem starting from cold, mechanic rekons EGR faulty only faults
showing up being EGR and fuel trim he says everything points to this even though it is a new valve fitted recently, my car is also fine once heated but MIL comes on. Any one
any experience of faulty parts from dealer???
JOHN
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In response to the suggestions its much appreciated
The car is currently running on shell fuel
I am thinking maybe the EGR even though I have cleaned this and changed the vac pipe from this to the throttle body.
Could a fuel filter change help.
Its weird tick over on start up not all the time is like its really lumpy blip the accelerator a couple of times and it clears itself.
I shall be checking the EGR and the air intake and the filters at the weekend.
Shall also have a look at the spark plugs and leads.
So far I have not seen any EML appear and shall be doing the paper clip test for piece of mind.
The weekend is going to be busy :-/ ::)
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Think I may have solved all my troubles spent yesterday removing the sump to remove the alloy plug that wouldn't come out, now removed and fitted a new plug thank god the sump is steel, new plug fitted and sump refitted and this morning no signs of oil leaks.
Fitted some new plugs as the one which were in there the porcelain bits were turning a nice shade of brown.
Fresh oil and filter change car now ticks over lovely no lumpiness and I changed the leads today for good measure.
Also been having a coolant problem hopefully this is also now sorted found that one of the jubilee clips was slightly loose to the HBV so it was weeping, been doing this since I replaced the thermostat guess water is going round as it should do now.
Shall be keeping an eye but in all its been a pretty busy but worth while weekend
Just hope no more goes wrong.
Just thought I'd update as its been a while since I have been on here.
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:y
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:y
Cheers for the thumbs up
Still not fixed unfortunately even fitted a new dispack to see if the lumpiness on startup would go but no its still there.
Thinking my next option is to check egr valve again and if its not the issue then compression test it is.
Its weird cos when all the lumpiness happens its goes then engine is steady as a rock mainly occurs when on choke if it has one at initial startup.
Car now since replacing plugs leads and dispack pulls like a rocket shall be checking the timing at the weekend for piece of mind.
Checked the vac pipe from the egr and its sucking air no problem.
So still doom and gloom at the moment.
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Has anyone got any other ideas other than the previously stated.
Any ideas are much appreciated :y
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EGR only really has an effect at cruising speeds, not idle, if I understand things correctly. Its used as a means to lean off the mixture to increase cruising consumption as opposed to idle settings.
If idle is lumpy, then the Idle Control Valve is the normal culprit, or an air leak of some descriptionb. try squirting carb cleaner round pipes and joints to see if there is any idle speed effect when the goofy juice gets into the intake system. Change in revs is the giveaway.....
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EGR only really has an effect at cruising speeds, not idle, if I understand things correctly. Its used as a means to lean off the mixture to increase cruising consumption as opposed to idle settings.
If idle is lumpy, then the Idle Control Valve is the normal culprit, or an air leak of some descriptionb. try squirting carb cleaner round pipes and joints to see if there is any idle speed effect when the goofy juice gets into the intake system. Change in revs is the giveaway.....
Cheers for the heads up shall be having a good look at the weekend, I know that the ICV the top bolt thread is fubarred so it could be the join, trouble is it only seems to happen when the engine is cold. :y
Shall try the carb cleaner idea and see how I get on
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EGR only really has an effect at cruising speeds, not idle, if I understand things correctly. Its used as a means to lean off the mixture to increase cruising consumption as opposed to idle settings.
If idle is lumpy, then the Idle Control Valve is the normal culprit, or an air leak of some descriptionb. try squirting carb cleaner round pipes and joints to see if there is any idle speed effect when the goofy juice gets into the intake system. Change in revs is the giveaway.....
;D
that should read 'cruising consumption figures'........ ;D