OT (sort off).. FAO TOM or other mechanically minded ppl (Fiat Punto 1.2)

[Paul R]

Hi

my girlfriend has a fiat punto 1.2 the same as the one in the bravo i believe. its a 2001 yreg, not the sporting though, it has a 5speed not a 6speed.

basically, she got a bad miss fire, and it was driveable, this was solved buy changeing the spark plug leads , and we also changed the coil pack as a friends used i diag on it and it said the coil pack was at fault.

now since we have changed these the misfire has gone but now it stutters between 2-3k as if its not getting enough air or fuel but then it clears, it drive smoothly untill she has to put her foot down or just accelerate.

she is just going out to get some new plugs, as its really the last thing i can think off... its only done 36k, so the fuel filter etc should be ok...it is due a service which includes airfilter (although it looks quite clean) oil and filter so spark plugs arent due but i though it best to change them anyways...

any suggestions?

thanks for your time

Paul R

 

[Tom]

How long was it driven for with a missfire?

 

[Paul R]

about 20mins but very slowly (really slowly) back to the house where it didnt move until fixed

Paul R

 

[Paul R]

about 7mile ish?

Paul R

 

[Tom]

How long since the missfire? It could just have fouled plugs.

 

[PAul R]

well the car was off the road for 3-4 weeks (holiday) then was used for a week with it stuttering then off the road for another week (holiday again) and we have just got back and we are trying to fix it.

the first time it was fixed it was dont buy my girlfriends dad who just replaced the spark plug lead that was arching out (dont who why it was) we changed the rest of the lead over today and now the stuttering seems to be getting more regular.. she just called to say she has got some plugs but the car now stutters all the time on acceleration, before it would clear.

the spark plug leads are not fiat parts and they are all deffinatly longer then the fiat origonals, i would have thought that the length of these would be very important? but they are supposidly the correct set for the car!

do you think the spark plug just might be shagged from running without a spark for that time it was driven on?

Paul R

 

[Tom]

Spark lead length is not critical, good connection is.

The fact its getting worse is worrying. One danger of a missfire is petrol gets into the cat and melts it, blocking the exhaust.

 

[Paul R]

well, the plugs are in now and its running alot better, but it still does the stuttering back at 2.5k but instead of 4-5times it only stutters once then goes ok...

what do you think now? bit worried about the exhaust?

Paul R

 

[Tom]

What did the old plugs look like?

 

[Anonymous]

Sorry to cut in, but I dont think it could melted the cat. I have driven my delta for 2 months whit back fire and no damage, but then again.....

sven

 

[Tom]

On newer cars the cat is much closer to the engine to warm it up quicker.

I've done ~40 miles with a missfire BUT I have a metal monalith cat rather than a ceramic one.

Its very unusual for them to melt though.

 

[Paul R]

well three wer clean and one was slightly burnt up browny kind of colour, i dont know whether this cam out of the same cylinder as the one which had the missfire as i didnt know which one had it but i would have thought it was...

Paul R