I've been having trouble recently with my Vauxhall Astra 1.4 H reg recently with it juddering and losing power when conditions are cold and damp. When the engine warms up it runs fine.
Now I've just been out to the car (it is 12am) and very dark, cold and damp, so I thought I'd check to see if there was any High Voltage arking coming from the HT leads and I noticed I could see intermittent small blue flashes coming from the area where the end of the HT leads make contact with the spark plugs.
The sparking seems to be occuring across all the HT lead contacts just above the spark plugs. Very small blue points of light flashing what appears to be randomly. There does not appear to be any arcing anywhere else across the length of the leads.
Is it normal to see small blue flashes there or is this a sign that the HT leads need replacing and could be the cause of judder when I'm driving the car when it's cold and damp?
I've changed the spark plugs & checked the distributer cap which looks fine.
Mack
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Your HT leads may be the originals and are old and perished thus the sparks. Replace the HT leads with a good quality set and fix the problem. Did you mean it was 0001 hrs and was dark rather than 12 am. Regards Peter
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Hi Pete
Yep! Thats right it was just after 12 midnight I was looking under the bonnet. I'm going to buy some HT leads later today. I'll reply back as soon as I've fitted them.
Mack
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Vauxhall's own leads are the easiest to fit as they are exactly the right length for the particular engine - other leads seem to give you far too much lead for some of the plugs as they are a compromise to suit several different engines. About £40 the last time I bought some from Vauxhall. Halfords do some Bosch ones which were also a pretty good match in terms of length & quality and about a third cheaper. Common sense I know, but only do one lead at a time!
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About £40 the last time I bought some from Vauxhall.
£22.27 from Autovaux - should be genuine Vauxhall parts as well.
www.autovaux.co.uk/StockList.asp?carID=17&cat=25
A lot of the third party lead sets don't have the metal plug caps, which are necessary due to the heat output from the exhaust manifold.
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Mac, excelent doiagnosis tool is the dark. As you have seen your sparks are escaping through the insulation of the HT leads onto the damp surface that forms on the leads at night.
Dont forget to replace the HT lead from the coil to the distributer as well. Clean the spark plug bodies (or change the plugs), Clean the top of the coil, clean the distributer cap inside and out.
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Hi
Thanks everyone for replying. I went earlier today to a local store and bought a set of Champion HT leads - the bloke in the shop went through his book to ensure they were the right ones for the Astra 1.4, he ordered them, and then I called back to shop 2 hours later.
The cost was just under £20 quid for the full 5 leads.
I fitted them without any problem. There doesn't seem to be any excess length or dropping down of HT leads near any crucial metalic parts in the engine and snapping the connectors on was easy and they fit very snuggly.
Car seems fine now. Left it for a couple of hours in variable weather, from mid afternoon to about 9:30pm with mixed weather conditions including a bit of drizzle. Then stared car, checked under bonnet and I couldn't see any sparking above the sparkplugs. Drove the car from a cold start and it seems to be running fine now.
Fingers crossed thats sorted the problem.
Thanks everyone.
Mack
ps: I did do a visual check of the dizzy cap and that looked fine. I did need to clean a bit of dark matter off the rotar tho and the contact points were a bit dull so I gave them a quick buff with wet and dry.
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Mack here again
Before I replaced the HT leads on my Astra 1.4 I also increased the engines idle speed because the choke was not working at all when weather conditions are cold. I normally would need to keep on revving until the engine ticked over. I don't need to do this now as the choke kicks in first time with the idling point set higher. I do notice tho that the engine revs at a higher pich than normal on starting the car. It then drops in pitch after about 5 mins to an acceptable level, the tone of the car is slightly higher than it was originally.
By adjusting the idle speed does this affect an MOT?
Mine is due next week and I'd hate the car to fail for adjusting it.
Mack
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ps: there's no plastic cap on it(I know thats there to stop people adjusting it). It was like that when I bought it and it has previously passed an MOT without any problem.
Mack
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if the revs are too high they will fail it...they will test it at the manufacturers recommended speed..if this isnt correct,they will assume that something is wrong and fail it..
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www.storme.co.uk
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With respect,testers cannot just 'assume that something is wrong'.If it is really revving they could say they would not be able to perform certain tests.The vehicle must idle for testing purposes-brake and emission for example.Increased revs will increase emissions,if it seems a little fast why not reduce it?
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Just a point. If you are scraping off deposits from the rotor and cap points, it is time for renewal. A Bosch technician once told me that people forget that electricity travels along AND through the deposits. Constant removing them shortens the gap. Given your problems, and the cars age, the key with the important area of electrics, is to maintain what is the weakest part of the car, by good preventative maintanance. A new cap and rotor is probably £15. Don't skimp. New plugs as well will give you a total renewal of the system, and peace of mind.
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Thanks everyone
Car seems fine now. No more juddering at all when cold and damp.
I've got the MOT tommorrow (Tuesday). Checked everything visually and it seems ok.
Regarding increasing it's idle speed slightly I only notice it revs quite high on cold start up then goes down through the 3 steps to a level which is audibly a low rev. Listening to it, it does not appear to be over revving once the engine has had about 10 mins to fully warm up, and the choke works perfectly now.
Is the fact that the revs start high on cold start going to affect the MOT bearing in mind once car runs idle it audibly sounds quiet and low ? (are those first 10 minutes crucial regarding emmisions).
Excuse my naivity and thanks for everyones patience regarding this as the only way I can gauge the revs is by listening to the sound of the engine during it's warming up phase, ie: engine sound high on start up, then after 10 mins the idle speed is a low purring tick over.
Mack
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Your engine should be hot during the MOT test - how it behaves on choke, just after you have started it should not be tested.
If you watch the test being done, make sure that the engine is warm.
If you can't be there to see the test, make sure that the oil temperature is recorded on the emissions check sheet, and that the oil is hot.
number_cruncher
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MOT result - It Passed
Thanks again to everyone for replying.
My Astra 1.4 (H reg - 1991)managed to pass the MOT without any failures. Not bad for a car I bought 2 years ago for £290 and this is it's second MOT since I bought it. The engine still purrs like a kitten.
This is a great web forum for advice. Thanks eveyone.
Mack
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