I always run my car (R plate 98 Vectra 1.8 GLS) until it has completed its warm up cycle, however on Sunday events conspired against me and after moving the car forward about a meter or so after its first (very cold) start in the morning I had to switch off and attent to something else. I hoped it would not be a problem as I did not attempt to start the car for 5 - 6 hours after the aborted journey. However the car refused to start until it was churned for a painful amount of time, it did then start with clouds of smoke, popping banging etc then ran as per normal. At this point what was the correct thing to do, (a) take it for a short run (but long enough to bring it up to temp) (b) take it for a long run, (c) drive gently (d) drive hard.
Which combination of the above??
Also is there a correct procedure to start a car in this condition to minimise the damage caused by the unburnt fuel in the Cat?
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Vern
I've had the same thing happen to me once or twice in exactly the same circumstances - hire cars I wanted to move on the drive. Seems no option but to floor the throttle and keep the engine cranking 'till it starts.
I've always run the car for a mile or so until it runs cleanly and is just about up to normal temerature, and found it's been fine next time. It seems you just have to run it long enough to get it off the cold start portion of the ECU programme.
Regards
John
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My car did exactly this this morning.
I moved the car off the drive yesterday morning and never moved it since then. Come 7:30 this morning I tried to start it and nothing. Cranked and cranked and when it did fire it died off again, even with some revs. I tried again 5 minutes later and got it started and went to work.
The car did produce large amounts of steam (it usually does in cold weather) until it got warm.
The thing is, I have done this a couple of times before and never had a problem.
Is this the cause or could it be symptomatic of something else (immobiliser)?
Jon
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Jon wrote:
>
> My car did exactly this this morning.
>
> I moved the car off the drive yesterday morning and never
> moved it since then. ......
> ...The thing is, I have done this a couple of times before and
> never had a problem.
>
> Is this the cause or could it be symptomatic of something
> else (immobiliser)?
>
> Jon
It may be that you have just got away with it until now, I think that my problem and possibly yours was due to the very short time it was started combined with a particularly cold morning. I doubt if it is an immobiliser problem.
This problem is very well documented however I have never come across any advise on what to do if it happens.
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This was posted by HJ on 26 Nov 2001.
Start Quote
"Author: Honest John (---.as.wcom.net)
Date: 26-11-01 17:59
...... the advice I gave about this. But there are a couple of ways to get a flooded catalysed car started. One is to take out all the plugs and let the neat petrol in the combustion chambers evaporate away. The other is to isolate the cold start instructions from the ECU to the engine (equivalent flooring the accelerator pedal to give a flooded non-cat car maximum air to sort the mixture out by ). However, this last method could damage the cat.
HJ "
End Quote.
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jack wrote:
>
> This was posted by HJ on 26 Nov 2001.
....... flooring the accelerator pedal to give a flooded
> non-cat car maximum air to sort the mixture out by ).
> However, this last method could damage the cat.
>
> HJ "
> End Quote.
All very well and good, but the original question was what then? short drive, long drive, easy drive, hard drive?? Or as he damage then bueen done and it no longer matters?
Also how does unburnt fuel in the cat evporate out through the holes left by sparkplugs? I don't imagne that much will get out past the valves.
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Big Vern:
1. As to what the original question was, do a search and you will find out.
2. As to whether |HJ's advice is valid, why don't you send an e-mail to HJ to question his wisdom?
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jack wrote:
>
> Big Vern:
>
> 1. As to what the original question was, do a search and you
> will find out.
I was refering to my orignial question at the top of the thread, which was what do you do when you have got the car started, take it for a short run ...........
>
> 2. As to whether |HJ's advice is valid, why don't you send an
> e-mail to HJ to question his wisdom?
I was thinking aloud hoping that somebody would expand the posted advise with some techincal detail, this is an annoying habit of being an engineer, question everything and belive nothing. It is a bit like the annoying child that asks why? to every answer you give them, until you lose patience as shout " It just is!" :o)
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> > 2. As to whether |HJ's advice is valid, why don't you send an
> > e-mail to HJ to question his wisdom?
>
> I was thinking aloud hoping that somebody would expand the
> posted advise with some techincal detail, this is an annoying
> habit of being an engineer, question everything and belive
> nothing. It is a bit like the annoying child that asks why?
> to every answer you give them, until you lose patience as
> shout " It just is!" :o)
Big Vern,
Thought you were going to say because you didn't have a tin hat so as to avoid the slings and arrows from HJ's wrath due to posing a question twice.
oo err missus!
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Vern
Engineering reply, from Mechanical Engineer (as bets he understands it):
The problem is, I believe, is that the ECU gets part way through the start up sequence when the car was switched off, and for some reason doesn't reset.
It may be some programmed in 'safety' system, but the ECU cannot 'detect' fuel in the cylinders, or cat, as there is no mechanism for it to do that.
I don't believe that removing the plugs and venting the cylinders will be of muchy use. It may help if the plugs are wet with fuel, but after an overnight stand I doubt it.
Flooring the throttle apparently eventually allows a cold engine to start, even though the fueling is stuck at some intermediate position. Bit like starting a carb fed car when the choke is faulty.
Damage? Well, there may be some excess fuel in the cat, although I doubt it if it's been left to evaporate overnight, and given the cat runs red hot anyway, I doubt the odd drop of fuel will cause major damage if it's not repeated too often.
regards
John
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Big Vern:
I am an Engineer myself.
1. It is unlikely that you will have done much damage if the incident was a one off. just do not repeat it too often.
2. Regarding whether unburnt fuel will vapourise thru valves/plug-holes, yes if you leave it for long enough. I suggest at least 8 hours in the Sun on a windy day. You may not get rid of all the fuel, but this it is a case of damage limitation - better to vapourise some than nothing at all. Wothr a go because all you have to do is remove/refit the plugs after the said time has passed. Oh yes, and it will do no harm to gently push the car back/forward to get valves open in turn on every cylinder - say every couple of hours - to ensure you have got some air flow thru each cylinder.
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It's usually due to the hydraulic lifters pumping up and holding the valves open. Symptoms are that the engine spins over very 'freely'. The only way round it is to hold the throttle pedal to the floor to initiate 'clear flood' strategy on the fuel system (shuts the injectors down) and crank continuously until one or more cylinders fires up. Keep the revs up until it runs cleanly then give the motor a long hard run to get the cat up to temp to clean itself. If the engine is simply flooded from being stopped a few seconds into a cold start the same applies.
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Very useful reply, which mirrors information I have seen elsewhere. However I have two further questions on the topic:
1 Why should valves end up not properly closed? Surely the pressure of the valve return springs should be more than adequate to restore the hydraulic tappets to their correct length.
2 Why does this seem to be a problem only with ECU-equipped cars? Hydraulic tappets have been around since well before ECUs emerged and I don't recall complaints about poor starting then.
3 What fuelling condition applies when this difficult starting condition occurs? My thinking is that the ECU, having detected a previous cold start with an incomplete warm-up, only commands fuel injection as if the engine were hot. Hence the resultant situation is of trying to start a cold engine with no choke available - which is obviously difficult. Reduced compression due to leaking valves only makes things much worse. Does any one agree or have definitive information?
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I'm just glad I run a diesel.....
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I've never had this problem with either my last Cavalier (16V SRi) and my current Honda (2.0 SE). I regularly reverse out of the drive to let my father out, and have never had troube starting again later. Is this problem confined to certain manufacturers/models, or is it particular cars?
Andy
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Andy P: I have no personal knowledge, but I suspect it must be some manufacturers who programme ECU's on their cars without allowing for all the diffferent situations in which cars are started and stopped. They must assume that everyone drives at least 5 miles after every start!
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Never have this problem with my Laguna and it isn't that rare that I drive it just into or out of the garage from a cold start (altho I obviously avoid doing so).
Sounds very like it is a bit of poor programming by some manufacturers - but you would think this might have come up in their testing?
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Laguna man is lucky! We have a '96 Volvo 850 Estate with the 2.5L 10v engine (with Fenix ECU). This has the ECU cold start problem very badly, with the ECU refusing to reset even after a week's rest. Endless engine churning with the throttle in varying positions between closed and fully open seems the only way to get it restarted. Our local Volvo Service Manager denied having come across this problem before (at least until he asked one of his technicians who had had an identical experience!).
Interestingly the Volvo Club website refers to 850s and 70s as being particularly prone to starting problems, possibly aggravated by the valves not closing properly due to the problem referred to elsewhere.
I have also had the same problem with an R registered Mondeo 1.8, but if I remember correctly the ECU would reset after a period of six hours or so.
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