Technical Smoking multijet.

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Technical Smoking multijet.

Schrimy

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Here a good one for you.
My Car is an 07 multijet. With 67K on it.
Three times now its done the following when in traffic just doing stop start type driving.
The water temp gauge is normal on three bars, normal for this car that is. It starts to sound like an old tractor, ‘Knocking’ or pinking I think it is called. Smoke comes from the exhaust. Not black or white smoke but a sort of grey colour. And there is plenty of it. It also will drop on to three cylinders for a second or two. Blipping the throttle makes more smoke come out but then it will stop, but a minute or so later it does the same. Normal driving seems fine. It just seems to do it when the engine is on tick over for some time. The fan comes on at full speed. But there is plenty of water, no leaks and the radiator is at normal temp. When I get out of the car the exhaust is red hot and you can smell the hot metal.
I’ve checked the ECU with Multiecuscan, no errors except for a low signal from the preheater control box, but I don’t think this is connected as the glow plug light does come on after starting, but its done that for ages.
I took it out for a run today and it did the same, again when in traffic. I was recording the injector correction readings. At idle two are 0.2 ish and one is 0.3ish one 1.3ish!
When running they are all over the place some reading 1.5 some 0.2 and anything in between. I’ve no idea what this means and its perhaps unimportant.
Any ideas what might be causing this smoking and rough running issue?
Thanks.
 
Dodgy injector? You could try putting some injector cleaner in the tank then take it for an Italian tune up. The other possibility is a problem with the EGR valve but I don't know much about them in Fiats.
 
Thanks for getting back to me.
I checked the EGR on Multiscan and it seems to work.
The DPF says 102% so I've no issue withthat. I did a forced purge thingy about three months ago. It went down a bit. Made no difference at all.
Dodgy injector, well yes I did think that , but how can I tell, what sort of readings should I look for in Multiscan?
Thanks again.
Chris.
 
You can get a leak-off kit to check how much fuel is being returned from each injector. I've never used one, so can't comment on them, but it looks fairly straightforward:



The kits are cheap on ebay. They look like little more than a few lengths of tube and some graduated bottles.
 
Thanks for getting back to me.
I checked the EGR on Multiscan and it seems to work.
The DPF says 102% so I've no issue withthat. I did a forced purge thingy about three months ago. It went down a bit. Made no difference at all.
Dodgy injector, well yes I did think that , but how can I tell, what sort of readings should I look for in Multiscan?
Thanks again.
Chris.
I have no idea but it might be possible to tell which cylinder is not firing by the temperature of the cylinder head or the exhaust.
 
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I had an injector which was leaking back from the cylinder on my Picasso. The garage sprayed it with a release agent, let it work in, pulled it, sprayed, pulled and so on. It took them quite a long time to release it. Fortunately they only charged for the actual time they spent on it, not the soaking time as well. They couldn't get the other injectors out. They did say a lot of people try prising them out and hammering and this knackers the cylinder head.
 
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