12 replies to this topic

[Tomf]

Ok well i know this is a mini forum but iv got a problem with my punto and i dont have a clue what could be up so any help would be great.

The car is a 1.2 8valve MK1 Fiat punto.

Well last week i changed the headgasket on my punto,, chaning the:

Head gasket
Cam belt
Cam belt tensioner
HT leads
Spark plugs
Coil pack
All filets
Oil

I then fired the car up and it was all running fine, then drove it a 10+ miles into town everything seemed fine, maby a little slighish.

I then went to town for about 4 hours and went to drive home, so i fired the car up, it all seemed normal, drove about 100meters down the road and the car just died.

When timing the engien up i turned it over about 5 times checking the timing markes every time and it all lined up, also there is clearance between the valves and the pistons when at TDC, so even if the timing was out it wouldnt bend a valve.

So now when i go to start the car if i have my foot flat on the floor and after about 20 seconds of turning it over it will splutter and just about idle, then after keeping my foot on the floor for about another 30 seconds it starts to pick up and rev, so it seems like at first is only firing on 2 or 3 cylinder then starts to fire in more after time.

Although it seems like its fore that an electrical firing problem, i stuck the old plugs, leads and coil pack back on and it still had the same problem.

So does anyone have any idea atall what could be the problem as i really dont have a clue what could be up with it nore did the recovery guy, that had been working in garages and then for the recovery company for 33 years.

So if you have the slightest idea of what could be up please say.

[1071s]

Hi, I can't help directly, but have you tried the Fiat Forum ( www.fiatforum.com ). They are a pretty good bunch - someone should should be able to point you in the right direction.
Off the top of my head, possibly an ECU or sensor fault?
Hope that helps, good luck!
Cheers, Neil

[Tomf]

Yea i made a post on there, but they dont seem know what could be up

Ill get a compression test done and see if that shows anything up, but i really dont have a clue what could be up, becuase i have checked the timing loads of times, changed back to the old ignition stuff and it still doesnt work

[T.Harper]

why did you change the head gasket? Had it blown? Did you get the head skimmed before putting it back on? If it's an alloy head you should have really skimmed it as these easily warp. I did a seicento a few years ago that needed similar

[Tomf]

Yea the headgasket blew, but it wasnt a bad blow it hadnt really blown through the gasket, just warped it a little, so i didnt bother getting the head skimmed, but im not loasing and water or oil, so i dont think its down to the head gasket...

But a compression test will confirm this...

[Purple Tom]

Tom - check the crank sensor - it sounds to me like you could possibly have dislodged it or possibly the wiring to it when working in that area. If its the 1.2 8V FIRE engine then the crank sensor is at the cambelt end of the engine using a toothed pulley (as per MS etc).

Would be worth checking that as a fault there can cause the sort of problems you describe. It could well just be loose so have a good look at it.

Tom

[Tomf]

Cheers tom, i also thought that could be the problem, but i took it all off cleaned it up but still the same problem

I guess i could order a new one a try that.

[Purple Tom]

Well I've just been doing a bit of reading on the Fiat Forum that we're a member of because of Jenny's 500, and apparently those sensors can be very intermittent when they begin to fail, eventually failing completely. I guess the thing to do is to check for whats missing when the car's having a wobbly - i.e fuel or spark (or both?). You might be able to narrow things down a little bit on that.

[Tomf]

Yea well its defo getting fuel as the plugs are wet, but i didnt check for a spark, ill do that next.

Could the crank sensor mess up the spark?

[Purple Tom]

Yeah, because the crank sensor tells the ECU where in the combustion cycle the engine is (relative to TDC), and from that it generates the spark at the right time. Without a signal from the crank sensor it won't generate a spark at all. So if the sensor is intermittently faulty it will cause the engine to run sluggishly at times, sometimes cut-out and other times not start at all.

I had the same trouble with the crank sensor on the Mini not long ago.

[bebbinator]

check the cam senser

[Jack Jones]

cranksensor, cam sensor, compression check if you didnt skimmed head, could be warped and loosing compression between cylinders although that fault dont sound like that is the problem

what syptoms did you have to do headgasket???

[Tomf]

Ok well i spent a bit of time looking over the car today, it was getting fuel and a spark, so i did a compression test and there was next to no compression in the middle two bores, so i started to strip down the head and found the problem straight away.

I got the rocker cover off and found that it was being starved of oil and this had caused two of the cam followers to sieze, so i got the head off and found that i had very studidly had put the headgasket on upside down, thus blocking the oil vay to the head

So i tapped the valves back in the had the cam followers stuck and this knocked the followers out and the seemed to fit nicely and move freely, and the had very little wear on them, so the plan is to get the valves out the head, and see if i can lap the cam followers in and see if that will make the fit smoothly, if that faild then ill have to search for a new head. But the damage really isnt very much atall as i hadnt traveled very far with the problem.

Well i get to take the valves out, but my valve spring compressor wont fit the head as the valves springs are set into the head So now iv got to try and either find a way i can modify mine to bodge it just so i can use it for this one time or see if i have a mate with one of the compressors that will work on the head.

Once they are out ill lap everything together and see if im going to be able to use it again.

Luckly there was no damage to the pistong or bore, so once iv sorted the head it'll be fixed and i can get on with working on my minus