General 1997 Mk1 Punto 60 sx Misfiring???

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General 1997 Mk1 Punto 60 sx Misfiring???

mtleigh

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Apr 4, 2011
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Hello,
I bought my punto in January 2011 as my first car and i am no mechanic but am willing to give anything a try.
Recently my starter motor just completely failed so i went to the scrap yard and got another for £20 and fitted it myself.
When i tried to restart the car, at first it failed and i found that i had not connected a black wire. After connecting this back up, the car was running like a bag of s$$t.
I then found that there was a small air pipe disconnected which when i reconnected seemed to improve the problems a great deal (this was reconnected under the plastic covering that covers where the lamda sensor connects), however, the car before my starter motor failed was running just fine and now it seems to misfire constantly. The misfire is not as noticable in idle but as soon as you start moving it is more apparent. It does not seem to reduce at any particular speed but i am having trouble with it as it feels like the car keeps wanting to stall when i am slowing down and it takes forever to accelerate. Also my fuel acconomy is completely rubbish. Before finding the disconnected air pipe i got 7 miles off £10. now i am getting roughly 30 miles of a quarter of a tank.

I have changed a coil pack which i was told could be my problem, which made no difference. I have checked all the spark plugs which are black and sooty except for 1 which is a little wet (could be oil) but these are all within a couple of months old. At the same time these got replaced, i had an oil change, new oil filter, new air filter, new cambelt and new alternator and belt all doen by a respected mechanic.

I have checked all other connections and they all seem to be connected.

I have read that this could be a number of other things such as my Labda sensor, head gasket or ECU. I am just worried that this is going to cost me a lot of money and i am baffled that the problems only started since changing my starter motor?:confused:

Is this something obvious or is there something simple i can try to improve the problems? I only paid £400 for the car in January and don't really want to spend much more on it if i can help it.

Any help would greatly be appreciated :cry:
 
Mabee the cambelt has sliped a tooth? to me sounds like the coil packs are breaking down replace boath not just the one also it could b the lambda sensor but with u saying u have one wet spark plug sounds to me like a coilpack breaking down but then is the HG going or gon check the oil filler cap for a mayo color and oil in the warter if so then the HG has gon (n) but easy enough to do
 
Mabee the cambelt has sliped a tooth? to me sounds like the coil packs are breaking down replace boath not just the one also it could b the lambda sensor but with u saying u have one wet spark plug sounds to me like a coilpack breaking down but then is the HG going or gon check the oil filler cap for a mayo color and oil in the warter if so then the HG has gon (n) but easy enough to do

There is no mayo in the oil and no oil in the water. When i changed 1 coil and it made no difference, i then swapped the one i took off with the other one that i had left on and still no difference? Another point to mention which i am not clear about, is when reading this forum i found that the HT lead configuration, ie. which lead goes to which plug, differed from the Haynes manual. I tried swapping the plug ends with 2 and 3 plug and that made no difference. My dad said it shouldn't start if they are not on the correct plugs because of the firing order. i have put back to what the haynes manual states now but my dad things that is very strange?
 
There is no mayo in the oil and no oil in the water. When i changed 1 coil and it made no difference, i then swapped the one i took off with the other one that i had left on and still no difference? Another point to mention which i am not clear about, is when reading this forum i found that the HT lead configuration, ie. which lead goes to which plug, differed from the Haynes manual. I tried swapping the plug ends with 2 and 3 plug and that made no difference. My dad said it shouldn't start if they are not on the correct plugs because of the firing order. i have put back to what the haynes manual states now but my dad things that is very strange?


I am sure i read in this forum that if you look at the coils as if stood at the number plate and you count from top to bottom for the HT lead to plug connections, it stated going down 4,1,2,3. where as the haynes manual shows 4,1,3,2?
 
the reason your dad is puzzled is because the punto uses a "wasted spark" system. Old cars that your dad had would have used a distributor and each plug fired in turn; on the Punto 2 plugs fire simultaneously when the pistons in their cylinders are at the top (fine tuned by the ECU/cam sensor); one piston will have finished the compression stroke and the spark will ignite the fuel/air mixture, the other will be finishing the exhaust stroke and the spark will be "wasted"; this system avoids having a distributor/contact breaker/one coil system that was notoriously unreliable and uses 2 coils instead of 4 thus saving weight and manufacturing costs; it does mean that conventional plugs rarely last 10,000 miles.
If you problems ONLY began after the starter motor was replaced (well done by the way not an easy job for a tyro) then the most likely explanation is a dud electrical connection; suggest clean and check all connections, particularly the lambda sensor ones.
 
Don't confuse the firing order with the order of the HT leads.

Count the cylinders from the timing belt ("driver side") of the engine, 1, 2, 3, 4.

So, the HT lead from no.1 cylinder goes to the same coil as that from no.4 cylinder, the leads from cylinders 2 and 3 go to the other coil. That's why swapping 2 and 3 makes no difference. As long as 1 and 4 and 2 and 3 are paired to the same coil, the engine knows no difference.

I'm suggesting you have one faulty HT lead because one is wet, the others are dry.
 
You should find that the connections are stamped on the coil pack bracket.

I suspect a faulty HT lead. Try starting the car in the dark, peer under bonnet and look for blue flashes.

I have just liked under the bonnet in the dark and there are no flashes at all
:confused:
 
Strangely enough I went out this morning and it ran as explained above but just took it for another run and it was ok? As if I never had the problem. Maybe just a slight blowing from the exhaust?
 
I have had no problems with it now for 2 days??? if anything it is better than it ever was??????
Thanks to all for providing suggestions to help me fix it, i am just really glad that it is working again. Not sure at all what the problem was but it seems to have fixed itself. well for now anyway :)
 
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