Technical Combustion problem.

[ccavalles]

Good morning.
I am trying to solve the problem with my Seicento 1.1. The car had a faulty camshaft sensor wire. Sometimes it would stall and not run combustion properly. I have replaced the wire with a new one, but the car is still emitting smoke and soot. It starts on the first try, no problem with that. The injectors were cleaned. Curiously, it didn't pass the vehicle inspection this year because of emissions; I touched the wire and it passed without any problems. I removed the spark plugs and they were dirty with soot. I put them back clean, but it still emits black smoke. Any idea what it could be? I see all the wiring is fine, coils and wiring were also replaced with new ones not long ago. The catalytic converter is also relatively new, as are the sensors.
When running, sometimes it works correctly and other times it seems like it has no power. But it does not stall.

In the video, more black drops than usual can be seen. I have put some cleaner through the exhaust.

 

[bugsymike]

Certainly running very rich, can you get a diagnostic error code read using a good scanner, MES etc.?

 

[ccavalles]

Certainly running very rich, can you get a diagnostic error code read using a good scanner, MES etc.?

OBD2 no error code.

 

[bugsymike]

OBD2 no error code.

No live data / MES etc.
I have had flooding on cold starts with injection down to an issue with temp sensors.
Maybe others on Forum will have a suggestion.

 

[ccavalles]

In this case, the problem came when the sensor cable broke. It started to go bad and then it didn’t start anymore. After changing the cable, it now starts fine, but sometimes not completely smoothly. Now with clean spark plugs, we will see what happens.
The more cared for the car is, the more problems.

 

[bugsymike]

Cam side looks sweet, not impressed with the sensor lead you had to replace and looking at that spark plug I hope you didn't clean it with a wire brush as it destroys the insulation benefit of the ceramic around the centre electrode and causes misfires.
I had that shown me at a Ford Motorcraft lecture 50 years ago.

 

[ccavalles]

Cam side looks sweet, not impressed with the sensor lead you had to replace and looking at that spark plug I hope you didn't clean it with a wire brush as it destroys the insulation benefit of the ceramic around the centre electrode and causes misfires.
I had that shown me at a Ford Motorcraft lecture 50 years ago.

Well, yes I have used them. So following your advice, I will put new ones.

 

[bugsymike]

Well, yes I have used them. So following your advice, I will put new ones.

It was an interesting lecture, even sand blasting a brand new spark plug and testing it showed it started to break down earlier under load.
Ever after that, on all my customers vehicles when servicing I would gap and fit new NGK plugs, never try to clean them. My customers appreciated the attention I put into their vehicles and never queried the cost of a set of spark plugs.
If you just want to get rid of the soot until you know the problem is solved try using a gas blow lamp. Spark plugs are designed to be self cleaning if allowed to run at their normal operating heat range, this is why short stop start journeys are bad for engines , they always run better when at normal (90 degrees Centigrade roughly)
The NGK plugs were as a result of working for a Mazda Dealership in the 70s and seeing how reliable they were. Prior to that I have used Champion, Bosch, Esso, all sorts.

 

[ccavalles]

Thank you for sharing knowledge. You always learn something new.

 

[Pugglt Auld Jock]

It was an interesting lecture, even sand blasting a brand new spark plug and testing it showed it started to break down earlier under load.
Ever after that, on all my customers vehicles when servicing I would gap and fit new NGK plugs, never try to clean them. My customers appreciated the attention I put into their vehicles and never queried the cost of a set of spark plugs.
If you just want to get rid of the soot until you know the problem is solved try using a gas blow lamp. Spark plugs are designed to be self cleaning if allowed to run at their normal operating heat range, this is why short stop start journeys are bad for engines , they always run better when at normal (90 degrees Centigrade roughly)
The NGK plugs were as a result of working for a Mazda Dealership in the 70s and seeing how reliable they were. Prior to that I have used Champion, Bosch, Esso, all sorts.

You're the first person in a very long time to mention this Mike - about how centre electrodes can be damaged by cleaning.

Way way back we all used to grit blast plugs at every service. We had a Champion spark plug cleaning machine which used grit and compressed air, bet you had one too? Cleaning with a wire brush was discouraged because, we were told, metal traces could be transferred to the ceramic surface which could encourage the centre electrode to short to earth which could induce misfire. Then, one day, the the NGK rep gave us a break time talk about how the ceramic was a new formulation and much more liable to be degraded if physically abused so no more grit blasting or wire brushing or any other cleaning. Just gap if necessary and change as recommended. Now, of course, we're not even to attempt to gap modern long life plugs for fear of damaging the very brittle and spindly centre electrodes.

Our boss encouraged the manufacturer reps to give us talks like this and we loved it because the 15 minute tea break could often end up at half an hour! On reflection though, I think he was right to do this as we learned a lot from these talks, even if they were often slanted towards the manufacturer's product.

 

[bugsymike]

You're the first person in a very long time to mention this Mike - about how centre electrodes can be damaged by cleaning.

Way way back we all used to grit blast plugs at every service. We had a Champion spark plug cleaning machine which used grit and compressed air, bet you had one too? Cleaning with a wire brush was discouraged because, we were told, metal traces could be transferred to the ceramic surface which could encourage the centre electrode to short to earth which could induce misfire. Then, one day, the the NGK rep gave us a break time talk about how the ceramic was a new formulation and much more liable to be degraded if physically abused so no more grit blasting or wire brushing or any other cleaning. Just gap if necessary and change as recommended. Now, of course, we're not even to attempt to gap modern long life plugs for fear of damaging the very brittle and spindly centre electrodes.

Our boss encouraged the manufacturer reps to give us talks like this and we loved it because the 15 minute tea break could often end up at half an hour! On reflection though, I think he was right to do this as we learned a lot from these talks, even if they were often slanted towards the manufacturer's product.

We must have learnt a lot as youngsters, some of it I can still remember.

Another thing I recall around that time was Ford were looking at "Lean Burn Engines" to improve fuel economy and emission reduction.
Sadly politics got in the way and we ended up with catalyst's, I often wonder if the petrochemical industry had a big part in that, especially as the early cat's increased fuel consumption and also didn't work efficiently until until they brought in heated Lambda sensors as many drivers only do short journey's meaning the cat's didn't work efficiently!

A lean burn engine is designed to operate with a higher ratio of air to fuel than traditional internal combustion engines. While a standard gasoline engine requires a ratio of roughly \(14.7:1\) (stoichiometric), lean burn engines can run on mixtures as high as \(65:1\). This significantly reduces fuel consumption and limits greenhouse gas emissions. [1, 2]

That amount of fuel saving would not have gone down well with the petrochemical industry!!! But sadly us, the customer always pays.
Throw in a few scares about fuel shortages caused by foreign wars and other things to convince the public that the price rise is justified, but note, the price never falls back to pre event levels. Another point is generally there is always fuel for them to sell us no matter what shortage they claim. A few days with short supply at a petrol station to keep us anxious and then the tap is turned on again at nearly the same high price.

 

[ccavalles]

Good morning. The topic of current cars is crazy, too complicated, electronics, batteries.. It's all political interests. I have checked the Seicento with two diagnostic machines and the following comes up: code P0170. Any idea what the problem could be? Thank you.

 

[ccavalles]

Do you know the NGK reference for the Fiat Seicento?

NGK 2330 ?​

 

[bugsymike]

Do you know the NGK reference for the Fiat Seicento?

NGK 2330 ?​

I used to have all the NGK reference books but stupidly binned them when I retired.
This AutoData manual lists the Champion, can you cross reference it? There seems to be many options. For some reason they list the Champion for the Seicento, but not for other Fiats?

 

[Pugglt Auld Jock]

We must have learnt a lot as youngsters, some of it I can still remember.

Another thing I recall around that time was Ford were looking at "Lean Burn Engines" to improve fuel economy and emission reduction.
Sadly politics got in the way and we ended up with catalyst's, I often wonder if the petrochemical industry had a big part in that, especially as the early cat's increased fuel consumption and also didn't work efficiently until until they brought in heated Lambda sensors as many drivers only do short journey's meaning the cat's didn't work efficiently!

A lean burn engine is designed to operate with a higher ratio of air to fuel than traditional internal combustion engines. While a standard gasoline engine requires a ratio of roughly \(14.7:1\) (stoichiometric), lean burn engines can run on mixtures as high as \(65:1\). This significantly reduces fuel consumption and limits greenhouse gas emissions. [1, 2]

Funny how things like this get forgotten. I remember there being quite a bit of excitement about Ford's lean burn technology at the time but then, as you say, catalysers and all their associated paraphernalia became the adopted preference. It was around this time that the possibility of going to work for a relative of my wife's family who ran a couple of garages near San Francisco. My understanding was that he had a small specialist garage selling and maintaining European sports cars, especially stuff like MGs and Healeys, which would have been just up my street. This must have been mid 1970s? I started reading up about the, then just introduced, Californian emission regulations and stuff like smog pumps (which injected air to weaken the mixture) and Catalytic convertors. The Ford Lean Burn solution seemed a much better solution to me than the rather cumbersome after treatment they settled on. Why wouldn't you treat the problem at source and reduce fuel consumption at the same time? As you say, I wouldn't be surprised if the fuel producers weren't in the mix somewhere. Unfortunately within the next few years both Mrs J's parents and my father died and my Mum became very ill with emphysema - life long heavy smoker of untipped cigarettes. This, not surprisingly, knocked us for six for some time and the opportunity slipped away. I sometimes wonder how different our life might have turned out if we'd gone? One thing that would have been nice would have been the ability to more easily visit my sister who had married an American - a lovely and interesting man - and was at that time living further north on the west coast.

That amount of fuel saving would not have gone down well with the petrochemical industry!!! But sadly us, the customer always pays.
Throw in a few scares about fuel shortages caused by foreign wars and other things to convince the public that the price rise is justified, but note, the price never falls back to pre event levels. Another point is generally there is always fuel for them to sell us no matter what shortage they claim. A few days with short supply at a petrol station to keep us anxious and then the tap is turned on again at nearly the same high price.

 

[ccavalles]

I used to have all the NGK reference books but stupidly binned them when I retired.
This AutoData manual lists the Champion, can you cross reference it? There seems to be many options. For some reason they list the Champion for the Seicento, but not for other Fiats?

It is the Autodoc reference that is recommended for the Seicento.

 

[bugsymike]

It is the Autodoc reference that is recommended for the Seicento.

Note, Auto Data Trade Manual for Mechanics, not AutoDoc.

 

[ccavalles]

It is the Autodoc reference that is recommended for the Seicento.

 

[bugsymike]

It is the Autodoc reference that is recommended for the Seicento.

Sorry all I meant was the manual I have always gone by for many years is the one the trade uses.

 

[bugsymike]

Re your Error code p0170, it could be a faulty MAF sensor ( try running it unplugged so ECU goes for a base stored setting to see how that affects it) it can be a poor Lambda/O2 sensor, or an air leak on the exhaust, amongst other options.
A good diagnostic tool able to read "live data" may help.