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Discussion Starter #1
Hi there,

We have a 2004 1.6 Turbo Diesel CMax, 73000 km. Recently we have been experiencing irregular idling speed, particularly when the engine is cold, black smoke , and strange rattling noises combined with very jerky acceleration. Driving with higher revs in all gears alleviates the problem (2500 rpm upwards).

These faults don't show up all the time - however it doesn't seem to be combined with the cold/damp, as they also occur in dry weather. But the car runs a lot smoother after it's been driven about 20 minutes or so.

We've recently had the car serviced ( at proper Ford place) but they couldn't find anything wrong.(!)

Has anyone got any notion about what might be wrong? Any ideas would be appreciated.

Thanks a lot

flugus

Edited by: flugus
 

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the idling speed is the choke working.
black smoke is nothing. dont worry about that.. diesels do that. especially after a few years.
the rattling. thats diesel clatter.
basically when the car is cold (even if its warm out) its the turbo not working properly because they need hot air to work. nd if the car is cold the turbo is getting cold air. so its not working how it should. just lay off the turbo for about 10 mins after you start the car. thats common on all diesels. my brand new one does it. my bro's focus tdci sport does it. my dads volvo d5 does it. its common.
i've even seen "i love the sound of diesel clatter in the morning" bumper stickers
 

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Does the car get used mainly for short trips? If so a good old 'italian tune up' might be in order.
 

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Discussion Starter #5
Thanks everyone for your input.


Ravenger, yes, at present we have a lot of short trips and we have realized that the car runs a lot better when it's warmed up decently. When cold it sometimes judders horrendously, which disappears when you rev up to about 3000 without engaging the clutch, then let the clutch in again (or else just change down).

So we can live with it at present - maybe once we've been on a longish trip things might improve!!?

flugus
 

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Italian tune up: Once the engine is fully warmed up, take it on a motorway and drive in a gear or two lower than normal, so the revs are high, but below the red-line, and drive like that for a couple of minutes. It'll clean all the carbon deposits out of the engine. Only do that if you're confident that the engine is mechanically sound though!

I drive my car to work one week in three, which involves a motorway run. At least once that week I accelerate onto the motorway using near maximum revs, just to give it a bit of a clean out. The other two weeks my wife uses the car, which only gets used for short runs and never really warms up, which isn't good for the engine, hence why I thrash it occasionally.
 

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I think there are a few misconceptions in the various replies.

Firstly the1.6 tdci does not have a choke.
Cold start is taken care of by the main ecu adjusting fuel delivery to the injectors to compensate for cold running.

A turbo does not need hot gas to work. It works by using the exhaust pressure created by combustion. The fact that it getsw hot is a byproduct of combustion. An engine is more efficient in cooler air due to cooler air being denser therby aiding combustion. (thats why turbos have intercoolers)

Many diesels do leave some haze behind them especially when accelerating but if you have got a large quantity of black smoke then the engine is overfueling and the black smoke is a result of incomplete combustion.

You have to accept that the modern diesel engine is a complicated piece of kit these days.There are numerous sensors recording engine temperature, ambient temperature, air pressure, air flow into the engine just to name a few. These sensors tell the ecu how much fuel to deliver to the engine at what point in the combustion cycle. As a brief example if the engine temperature sensor fails to record the fact that the engine is hot the ecu will think that the engine is cold and supply excess fuel to compensate which infact it does not need and then you get black smoke.

It has to be to get by the emissions legislation.
I suggest that in the long run that you have the car put on a code reader to identify the problem thereby reducing the likely hood of replacing parts that did not need replacing.

Sorry for rambling on and good luck

Geoff
 

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As these engines do have EGR has a sticking EGR valve been checked. Excess EGR does cause a very "lumpy idle"
Try also checking how clean the air filter is as well as perhaps running an injector cleaner (redex or wynnes) through a tank of fuel
 

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Discussion Starter #10
We tried the Italian tune up (some time ago now) and it seemed to help a bit but we still weren't happy with it. The Ford people then found that one of the turbo pipes was faulty and replaced it, which made for a lot better driving but didn't seem to lessen the black cloud trailing along behind us. So in the end we took it back to the Ford place again and they reprogrammed the PCM module - that was a few days ago and now the car drives like new, no juddering or hesitation, no black clouds.


So thanks everyone for the input, thought I would just keep you updated.
 
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