Technical 1996 Punto 1.2 8v misfires when warm

[mk1Punto9675sx]

Hi all, hope this message finds you well. I need help with a problem on my Mk1 punto.

Recently I bought a 1996 Fiat Punto 75 SX. a few days after I bought it I noticed that it misfires when it's warm.

If I start it when it's cold it runs well with no issues, however, if I switch it off after it warms up, let it rest for about 10 to 20 minutes and come to start it again it takes more turns to get going and it starts working on 2 cylinders than on 3 and then after about 15 seconds it runs ok with an occasional misfire here and there.

Fuel consumption is very poor and it seems to be running lean.

Until now I just changed the plugs and HT leads and also put in some injector cleaner but the problem is still there.

Any suggestions on what could this be?

Thanks for taking the time to read my post. Hope you have a nice day!

 

[GrandePunto PL]

Do your homework folks!
It's very common problem with generation 1 Puntos (other too)!

Keywords for search engine:
- misfire,
- rough idle,
- hard/long cranking/starting,
- non-starting when hot,
- running lean (or rich),
- etc.

Typical answers: spark-plugs, leads, coils, TDC (crank) sensor, timing (belt skipped tooth), other sensors (temperature, MAP, "Lambda"), valve clearances out of adjustment, dead catalytic converter, bad fuel pump and/or filter or injectors, PCV "breather" clogged, throttle body, last thing head gasket. Also, scroll page down, you have "Similar Threads" listed automatically.

 

[mk1Punto9675sx]

Hi

Thanks for your reply, however, I had done my homework very well and nothing which was listed your message or indeed any thread on this forum seemed to be working. So after a considerable amount of time searching the forum and getting nowhere, I decided to do a little fault finding of my own.

Now I am no mechanic, however, I managed to arrive at the conclusion that the Fuel pressure regulator was worn out and was causing the misfire.

I replaced it and now everything is now splendid, the misfire is gone, the engine is running like clockwork and the car is back to normal.

:slayer:

Kind Regards and I hope y'all are enjoying the festive season.

 

[jimboy]

Good news then. Doing a bit of investigation work is always the first port of call with any fault, glad you got the old girl purring again.

Take note forum members, taking time to actually look & do bit of investigation work & get your hands dirty could save you time & money... Obviously at this time of year you should be making sure your chosen set of wheels is performing as it should. Keeping an eye on mature motors & actually checking the old girl over is good practise.

 

[varesecrazy]

[mention=92557]tony55s[/mention]