Looking about these are SPI, not carb, aren't they? Bugger. Adam - are all the plugs the same? Has it used any oil?
As Burnout is suggesting, this sounds like either a fuel injector or a spark timing issue, the fuel is being wasted, not burnt. I had one of those as a courtesy car, it gave me more than double in petrol what a diesel 300tdi discovery was returning me at the time. Uncomfortable as fcuk to drive but it was the most economical car I've ever driven even now. Just sounds like it's been thraped & generally abused tbh, unless it's actually leaking fuel. Under heavy accelleration I can't get mpg that low in my 307 which weights more than twice what the original Punto does.
You would smell a fuel leak if it was dumping that much petrol. Another possibility which I don't want to concern you about just yet is bad compression due to ring wear, but cross that bridge after the plugs have been checked and potentially the leads replaced. Please if you start the car before checking the plugs, get it up to temperature as plugs get soaked when the engine is cold. So give it a good 20min let the fans kick in a couple of times, shut it off and wait 10min before pulling the plugs. Also remember where each plug goes so you know which cylinder has a poor spark. If all four plugs a black and greasy after getting the car nice and hot then a more in depth look is required to check plug gaps, leads and coilpack before getting a compression test done.
There is no really reason to, if it were a carb and backfiring into the airbox then the filter would have been burn't to a crisp by now and it's something you can't help but notice when it happens. How ever its a simple single point injection system, similar to a carb but they don't backfire as it isn't full of petrol like a carb would be. OOOOOOOOOO single point injection, I wonder... On a cold morning when first started does it "hunt" for a idle point? I it does I know the fault which would result in rich running. EDIT: I would give both the idle control valve and EGR valve a clean with some brake cleaner. If the EGR (exhaust gas recirculation) valve is sticking open then the ECU injects more fuel to burn hotter in order to clear the blockage in the EGR, however an EGR may need cleaning due to the poor servicing. Let me explain, If the oil was left for a long interval between changes, then more than likely the oil control rings that help scrape oil from the cylinder wall on the down stroke become clogged and stuck, which results in burning of engine oil. This engine oil can then clog the crap out of an EGR valve but also create "oil/greasy" spark plugs. Bad oil control rings won't effect engine compression, so it's a little harder to test for. Personally with an engine in poor care, pop down to eurocarparts or alike and grab 5 litre's of flushing oil. It'll cost less than additives sold in halfords. Then do as the instructions recommend. I would grab two oil filters, there cheap as chips and help catch a lot crap this flushing oil will break away. This should resolve your fuel consumption issues.
People of Bit-Tech, I return. Popped out this morning to have a poke around the Punto again. Fuel lines = Fine Oil = Fine Plugs = Black Air lines = ... 90% fine. On the inlet manifold is a small (3-4mm ID) rubber pipe that connects to a small black box with an electrical plug on it (I have no idea on this or any other earth what the box does). The pipe was split at the base where it pushes onto the fitting on the inlet manifold. I re-routed the pipe, snipped the end off and put it back on. Plugs where all black with a little brown spot where the spark jumps over. Just soot , not oily or greasy. Ran with the air filter off (not driving, just to see what it did). All looks good, did look like it was spewing a bit too much fuel in, but the sucking air sound I noticed last time stopped (as I fixed that little pipe). I fixed the one pipe, didn't check the lamb sensor due to lazy and forgetfulness. Also video of the clatter - http://youtu.be/akOOMNvohiM Owner is now looking for a new(er) car now. @Burnout - I don't think it has ERG. I've seen they can sludge up, but I don't think this punto has one. At least I can't find anything that goes from the exhaust manifold back up to the carb bit. Also just realised I didn't give the exhaust a sniff ... damn memory. Its even written down in my book. @Archtronics - Yup, its still clean and dandy. @Landy_Ed - Good thing I have no idea how to check that sort of thing. It runs okay (other than feeling like a death trap and sounding like a tractor). @Krikkit - Oil is all level, nice and clear still. See how it goes with the pipe fix, then move on from there.
No EGR on that engine as it's pre-Euro 4 emissions and most small petrols didn't bother until they were mandatory (2001ish). Sounds like a dicky injector from that clatter, although it's very difficult to tell. The pipe you fixed sounds like it was going to the MAP sensor (Manifold Absolute Pressure), which helps the ECU figure out how much air is coming into the engine, thus how much fuel to use and when to spark. Chances are it should improve with that connected up without a leak.
It's a side-effect of recording on a phone - they pick up every clackety, tappety noise possible and make it sound bloody awful.
You know that one really loud clatter is has, that sounds like a lump of metal smacking about. You can hear that one with the bonnet shut standing away from it. Its a very noticeable noise.
Stick it on eBay as a no-reserve auction, someone will pay a couple of hundred quid for it, at least!
if the car has been poorly serviced , the punto has an issue of the oil spray bar clogging up and the cam runs dry and seizes . may be worth checking
An update for anyone who still cares. Since fixing the hose, the owner hasn't driven it. They have instead borrowed another car and are now looking for a new-er car. So now its rusting in a back lot. Waiting for the end. In other news, I found a Fiest and a Polo for under £500 and £700. I wanted to buy one just for a Practical Performance Car auto test thing they do.
That hose may have well been it, worth a try at least. The 1995 1.1 averages (germans have a website for this) at about 6.6liters/100km thats 42.8 imp. MPG
