Lantra (Elantra) 1.6 occasionally won't start from cold

I have a 99 Lantra 1.6 which very occassionally won't start from cold; just goes on cranking eventually flooding the engine with petrol. The only solution is to leave it for about half an hour or even until the
next day and try again. I would say its only 1 in a hundred times but can be very inconvenient if its an important journey ! I met someone else recently who has the exact same problem on his Lantra 1.6 so it must be some common ailment. I also notice that often when starting, the engine does not catch until the point where I release the key from the starting position and it then starts from its own momentum; like its not getting enough electricity to fire with the engine turning over under the starter motor. Compare this with my sister's Rover metro which fires up at the slightest touch of the starter. I have run an extra earth cable from the battery straight to the cylinder head which seemed to help but I have still had the problem since then. Once started it runs fine and has not been a problem when starting from hot. Is there any particular relay or connections that I should clean to help get more juice to the coil or any other reason for this problem?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

May be you have to wait 2 seconds to let the fuel pump go into pressure; you can notice this more when the tank is almost empty.
--
Zotto Sonica barbonica driver
http://www.flickr.com/photos/zottoida/
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Possible coolant temperature sensor problem?
(Just a guess-- don't replace without verification).
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Its not waiting for the fuel pump to prime Zotto; in fact I had the problem again today and as it was flooded with petrol, I left it 5 minutes and then started without waiting for the pump; it ran. Probably not the temperature sensor as when it does start, it runs fine; if it were the temperature sensor, I would expect it to run rough for a while? I'm sure the spark is just not powerful enough when cranking but don't know how to get a more powerful spark. Maybe the new ignition leads are rubbish as I didn't have the problem with the old leads ( I changed them because the insulation had gone on one lead due to oil rotting it); anyway to check these?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Have you the right spark plugs? If there is a leakage in leads you could see in total dark some little sparks somewhere around them.
--
Zotto Sonica barbonica driver
http://www.flickr.com/photos/zottoida/
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I think I found the problem. The new HT leads have double the resistance of the old ones e.g. the new longest HT lead is 7K ohms whereas the old one was 3.2K ohms. I also noticed that the spark plugs are the resistive type. Take all this resistance plus the voltage drop on the systen due to cranking the engine and hey, no spark at all ! I changed the leads for copper cored (self made) and now the car starts while cranking instead of just firing as I turn of the key ! Brilliant. Resistive HT leads are such a pain; always cause trouble. I think the manufacturer goes all out to reduce emf emissions which works very well if I can't even start my car ! Here is how I made the copper cored HT leads. The problem is of course the fittings for the coil pack and spark plugs which cannot be bought. To get around this, use the fittings from the resistive HT leads. Chop the cable off right next to each fitting. Screw in a self- tapping screw (I used a 1 inch one) half way; then saw off the head of the screw; file or grind the end to a point and screw on the copper cored HT lead ( you can buy this from car accessory shop). When both ends have been assembled, I mixed up some araldite and applied around the join to seal it and strengthen it. I'm not sure araldite is the best stuff to use as it can crack up in cold weather. Maybe some silicon sealer would have been better. I have noticed no interference on the car radio; although the leads are now copper cored, the plug caps and the plugs themselves are resistive so this helps with supression.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.