Problem Punto Mk1 1997 60k with injection warning light coming on and spluttering of engine

A few mts ago problem started with infrequent injector warning light on but got worse and in end was on most of the time and engine spluttering.
Replaced the plugs and O2 sensor and problem disappeared for a few weeks.
Problem came back but not as problematic except in cold weather car engine splutters when warning light on or just before it comes on.
Took it to local garage was unable to get monitoring equip to pick it up, unable to get it to repeat the problem prob testing it in warm garage environment.
Any suggestion?

Sounds silly, but try the master key (brown or burgundy). I had a mk1 with the warning light, misfiring & sounding like a bag of nails. The master key being used once sorted it all out.

Unlikely I know, but free and worth a go!

corkyhere said:

Problem Punto Mk1 1997 60k with injection warning light coming on and spluttering of engine

A few mts ago problem started with infrequent injector warning light on but got worse and in end was on most of the time and engine spluttering.
Replaced the plugs and O2 sensor and problem disappeared for a few weeks.

Took it to local garage was unable to get monitoring equip to pick it up, unable to get it to repeat the problem prob testing it in warm garage environment.
Any suggestion?

Click to expand...

Hi. Its a basic system..

The Lambda exhaust probe is sensing unburnt fuel...
from a misfire..?

Check plugs/ coilpacks.

Where is the car based..??


Charlie . Oxford

Tks to all, it seems to be related to un-burnt fuel in the exhaust, I replaced the plugs with a new set all set correctly and the coils seem to be ok unless it’s an intermittent fault but unlikely as I removed the plug leads in turn from spark plugs but couldn’t get car to start. The problem seems to get worse when conditions are cold and one can actually smell the un-burnt fuel from the exhaust. The garage I gave it to has an experienced mechanic and he can’t seem to locate the cause of the problem. I haven’t used the brown key with a while as the EMU was not recognising it. Car is in Ireland.

you don't say what engine, but being a 1997 its most likely going to be some form of fire engine... When you say the garage couldnt pick it up with their monitoring equip, do you mean they couldnt connect to the car or they just couldnt get any codes off it when connected. If the light comes on it should 100% log the code and it just be stored rather than active if you read it while the light is not on..

Id say coilpacks are a prime suspect, but you did not say you changed the ht leads, only plugs. I'd swap out the leads first as they are cheap and its never a bad thing to have new leads at same time as new plugs imo.

Could from the running problem described also be crank sensor failing, they tend to start with the odd flash of the EML and progressively get worse. And also tend to either start with it doing it more when cold and clearing or vice versa. But if it fails to send a signal you should get no spark and no fuel so unburnt fuel smell does not really fit the symptoms but I'd not rule it out. The ecu tends not to show the sensor as fault unless it goes completely open circuit and just logs misfires instead on each coil pack.

it does seem very strange there is no code if the light has come on but its most likely gonna point towards the leads or coil packs. I'd just swap them both if it were me, neither are hugely expensive. But do check the wires going to it for corrosion etc and run the car in the dark and open the bonnet and look for little blue flashes along the ht leads and particularly around the connection at plug and coil pack ends. If you see any blue flashes at all its almost 100% just going to be the leads themselves.

What I understand is the garage equip could not read the EMU so didn’t get any reading. The model is a 55 SX (1108cc - 5 door). Garage concludes as contributors on here its un-burnt fuel. Garage advice it’s probably a faulty new O2 sensor as it’s the only thing that could cause the problem. I suspect the same since it settled down when I replaced it initially then it flared up. The O2 sensor came off eBay and it has a 2yrs warranty so I will get back to them for a replacement. Since I had replaced the O2 I presume the Garage left it for me to sort out myself. I have cleaned the HT plug leads with wb40 all and could not find any HT leak and engine does not misfire when idle nor does sensor light remain on. Yesterday I let it run on idle for 20 min without a problem. It recently had a “roadworthy” test and there was no emissions problem with the test. Recently replaced the crankshaft sensor and the problem I was having with that was I could not start engine when hot or engine would cut out in heavy traffic probably due to black surface absorbing engine heat. What amazes me about it is some days its ok and more it a constant problem and I can actually smell the un-burnt fuel while drive as it splutters along. I plan to steep the old one in meth’s for a few days to install again, return the new one and await a replacement. See how I get on from there.

Multiecuscan free download with a cable plus a 3 pin adapter should connect to your ECU and read why the warning light is on.

agreed.. Even if you dont need it now its a massive benefit to have. And only a few quid outlay. Bearing in mind how many other cars are supported as well. I used it on cinqs, seis, punto, my partners new 500, my old alfa 159... Its an epic bit of software and the free version can read and clear codes

software here http://www.multiecuscan.net/

cables, you need one of these, and one of these.

And if the second cable comes with a disc, just throw it away it will just confuse matters. Just plug the cable in and windows should recognise what it is and installed appropriate drivers.

Agreed it is a great tool. I haven't yet had to use a three pin adapter but as blu73 has you have someone with first hand knowledge to help.

It will be cheaper and less frustrating than changing parts randomly hoping to cure problem.

Ordered and appreciate the help I have got.
Await delivery, tks again.

That's great .
It took me a couple of goes to get my vagcom lead to connect but that's due to my poor computer skills. Well with the effort.

I've just joined the Forum hoping for some help with an intermittent problem similarly on a Punto Mk1 1997 55 SX 64k initially occasionally failing to start but latterly also "coughing" going up hills & over speed bumps and last week cutting out completely. I towed the car home and as I had been suspecting a fuel delivery problem (blocking filter?) put a gallon in the tank thinking it might clear it. Charged the battery which I'd flattened overnight and next morning started OK. 2 days later it wouldn't start again so had to tow it home. Previously replaced the suspect HT leads which were a bit perished but problem still persisting. Going to try replacing the fuel filter unless anyone can suggest anything else please. Injection warning light operates as per the manual.


Gareth

Spark plugs last changed?

Thanks, the spark plugs were checked when the HT leads were replaced about a month ago. We were thinking it was an electrical/ignition problem then but couldn't find anything untoward. Having said that, being intermittent it's obviously proving difficult to pin down.

How many miles have spark plugs covered?
How did you check them?
Are they the correct spark plugs for your engine?

10,300 Checked by the garage where the car is now waiting to be looked at [again] on Monday so I'll ask them to make sure that they are as per the manual (which is in the car).

Just put new plugs in they are cheap and depending on what plugs are they could well be worn out.
It may not be the problem but they need changing and it rules out one potential cause.

You are doing right thing trying to get to bottom of this problem.

Keep posting updates with progress and hopefully someone will come up with helpful advice.
Where are you located ?
If someone is nearby they may help.

Crankshaft sensor diagnosed as faulty; new one fitted & all seems OK.