Sorry guys, know there are lots of various posts on this, most with the same issue, but want to see if there is anything I am missing.

8v 51 plate Punto, engine light been on for a good while now. Stutters if left a few days without running, and really badly indeed when it's wet - on a few occasions it has pretty much lost all power and stalled when it's really throwing it down.

I'd be surprised if it's ECU, sparks or colis/HT's as changed all those two years ago when the ECU packed in completely. Replaced with brand new Fiat item (not reconditioned), new plugs, leads, coils.

Had the plugs out, checked gaps and all good. Plugs all decent colour and not oiled up. Changed air filter for K&N, old one was pretty mucky, but no real change. Found hole in the air box too, but fixed that and still no change.

If anything, the stutter has got more consistent now with the new K&N. It pulls okay on 1/4 to 1/3 throttle but anything more it really struggles - feels like fuel isn't getting through or carburation is off. Once up the rev range and rolling at speed, it pulls ok, but anything lower down it tries to bunny hop! Engine light flashes when it gets really bad, but goes back to a solid light otherwise.

Any thoughts on what to check? Could coil packs/HT's really have gone in 2 years? Exhaust has always been a problem but had mid and rear replaced recently - if it was blowing near the headers, could that put the fuelling out this much?

All advice welcome.

Cheers

Toby

May be coil pack. could have failed and breaking down again.
Only other thing is take filter off completely and take for a short drive. see if it's any different. my guess is coil pack

had stuttering problems on a punto 1.2 8v at work, I changed the throttle body and it was fine

No carberation here my friend

We have a throttle body ( a flap) and In-direct injection

2 years is almost the life im finding of HT leads, and some "cheap" coil packs you can get

The coil packs are actually a service item according to Autodata

Check HT's And coils / Replace

A Sticky throttle wont help - a 1/2 hour removing and cleaning can help no end, probably should try this first

Any holes near cat is always going to mess up fueling

Ziggy

its probably that engine light being on zapping all the power
get some dilithium crystals in your fuel tank
worked for me when i ignored the eml advising i had problems, so might work for you too

Thanks guys. Ok, did wonder where the carbs were!! So throttle body is what you see once you remove the airbox - two flaps? How much comes away with that and is it easy to take off? Should those flaps move easily or are they actuated? As for packs and leads, any reliable brands worth getting? Did buy generics from local factors last time but had this problem for a year or more now so that would mean they only lasted 12 months! Can't get to this until monday but all advice gratefully received.

Throttle body removal is pips
follow this guide

https://www.fiatforum.com/punto-guides/307670-remove-clean-throttle-body-1-2-8v.html

ziggy

Great, thanks for that link ziggy. Wil try that Monday. It doesn't fuel consistently on tickover though, does throttle body only get involved once you press the throttle or would it also affect how it runs on tickover?

samtobuk said:

Great, thanks for that link ziggy. Wil try that Monday. It doesn't fuel consistently on tickover though, does throttle body only get involved once you press the throttle or would it also affect how it runs on tickover?

Click to expand...

The throttle body in the 8v's case is well pretty much a flap and a mounting point for the ECU

There is 1 sensor so the car knows how open the throttle is
The throttle body is as involved as the rest of the car, that flap connected to your pedal tells the ECU how much power you want
You plant the pedal
Cable pulls flap open
Sensor on side of flap see's this - sends message to ECU
ECU goes Time to power up the ponies
ECU alters timing, fuel delivery based of the numerous sensorial feeds and the power is made

If that sensor fails, the car will limp home, as it doesn't know how wide that throttle is! Well mostly on Motor controlled versions

Ziggy

Well, took the throttle body off, thoroughly cleaned (wasn't too bad, just a tad oily) and replaced. No real change to the problem, although it is definitely picking up quicker on the throttle, so clearly needed doing anyway.

Just sat revving in neutral, it revs fairly cleanly, but stutters on the over-run and burbles back to tickover. If I rev it to 2k and hold it there, it stutters every few seconds.

The exhaust does sound noisy, but more from the middle section where the flexi section sits. It has never been quiet though ever since I changed the original over - this current exhaust is only 6 months old. There is a small hole near the back as I can see that blowing a bit of fuel and smoke. Was certainly smoking a bit today, and seemed not to be burning fuel that well as quite a drip from the back.

Am probably going to drop it down to the fitters who put the exhaust on to get them to check it, but beyond that does it still sound like new coils and leads are the way to go?? If so, anyone got any specific brands that they know will be good for a few years??

Cheers all.

Toby

its not got a maf its got a map with so wacking a k@n on and expecting it to not gobble on itself in this weather aint gonna happen
a leaking exhaust adds to the woes
consider warm water injection to increase warm flow

ngk plugs
fiat ht leads.as aftermarket are crap for me
and coils can vary

ziggy

Well, bit the bullet earlier and grabbed some new coils and leads from the local motor factor - not brands that I know but hey!

Fitted them this afternoon, and seems to have done the trick. Much more power now and pulls cleanly with no stutter, so maybe it wasn't even running on all four? Exhaust is still noisy and still burbles on the over-run, but that must just be a leaky pipe somewhere.

EML is still on though, take it that needs to be reset, even if the issue has gone away? Does that have to be a dealer who does that, or can any garage hook up a diagnostic and tell it to turn off?

Cheers again all for the advice.