vauxhall astra - vauxhall astra - vauxhall astra cdti

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Wed 9 Nov 2016 20:59
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Hi my astra cdti is not doing the consumption I was expecting , it says on the computer that it is doing 35.9 mpg , when I go to it in the mornings it does not always start first turn and when it starts it puts a little smoke out , it has only started since the cold weather and had interior heater on , could it be glowplugs and egr thanks

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Wed 9 Nov 2016 21:09
vauxhall astra - vauxhall astra - vauxhall astra cdti - RobJP

Could be anything - though not likely to be the glowplugs, they only assist with cold starting.

If EGR was stuck, you'd expect performance to be down.

It could be injectors, airflow sensors, any of a load of other sensors. Unless you like wasting money, the best way of finding out what it might be is to get a (proper !) set of diagnostics carried out.

When was it last serviced ? What sort of mileage has it done ? How old is it, and what sort of journeys do you do in it (short trips from cold, etc) ?

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Thu 10 Nov 2016 08:27
vauxhall astra - vauxhall astra - vauxhall astra cdti - Railroad.

Glow plugs don't even assist with cold starting on a direct injection engine unless the outside air temperature is around zero degrees Celsius. Their main purpose is to reduce noise and improve emissions when the engine is cold. They switch off in usually under a minute after a cold start, so it's highly unlikely they're your problem.

Trip computers cannot be relied upon for their accuracy. You need to fill the tank, zero the trip, fill the tank again and note how many miles you've done. Divide the number of miles into the number of litres of fuel you've put in, then multiply that figure by 4.55 to give you miles per gallon.

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Thu 10 Nov 2016 08:34
vauxhall astra - vauxhall astra - vauxhall astra cdti - RT

I can't verify the information - but I've been told that the glowplugs on the Fiat diesels used by Vauxhall do run continuously, not just during cold start up - this was the explanation given for a 90,000 mile 150 CDTi running badly even when warmed up but ran fine after replacing glowplugs.

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Thu 10 Nov 2016 09:42
vauxhall astra - vauxhall astra - vauxhall astra cdti - Peter.N.

Fuel consumption does suffer in the cold weather for a number of reasons, first the oil in the engine and gearbox is thicker as is the grease in other bearings, combustion is less efficient especially when the engine is cold and the air is denser causing more drag.

I went to exeter yesterday in my 406 Hdi estate, in the summer it will do well over 60 mpg on that trip, yesterday 55 mpg going down and only 52 coming back. I have two of these cars and the are both doing about the same.

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Thu 10 Nov 2016 09:53
vauxhall astra - vauxhall astra - vauxhall astra cdti - RT

Fuel consumption does suffer in the cold weather for a number of reasons, first the oil in the engine and gearbox is thicker as is the grease in other bearings, combustion is less efficient especially when the engine is cold and the air is denser causing more drag.

I went to exeter yesterday in my 406 Hdi estate, in the summer it will do well over 60 mpg on that trip, yesterday 55 mpg going down and only 52 coming back. I have two of these cars and the are both doing about the same.

It also suffers as winter diesel has slightly less energy value.

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Thu 10 Nov 2016 10:42
vauxhall astra - vauxhall astra - vauxhall astra cdti - madf

If it has not been serviced, a blocked air filter is first check.

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Thu 10 Nov 2016 13:11
vauxhall astra - vauxhall astra - vauxhall astra cdti - Railroad.

I can't verify the information - but I've been told that the glowplugs on the Fiat diesels used by Vauxhall do run continuously, not just during cold start up - this was the explanation given for a 90,000 mile 150 CDTi running badly even when warmed up but ran fine after replacing glowplugs.

That's news to me. What benefit would there be in the glow plugs switched on all the time in a compression ignition engine? They could be switched on for DPF regeneration though. That would make sense. And also would be why fault codes are flagged and the engine entering limp mode if they failed.

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Thu 10 Nov 2016 13:19
vauxhall astra - vauxhall astra - vauxhall astra cdti - RT

I can't verify the information - but I've been told that the glowplugs on the Fiat diesels used by Vauxhall do run continuously, not just during cold start up - this was the explanation given for a 90,000 mile 150 CDTi running badly even when warmed up but ran fine after replacing glowplugs.

That's news to me. What benefit would there be in the glow plugs switched on all the time in a compression ignition engine? They could be switched on for DPF regeneration though. That would make sense. And also would be why fault codes are flagged and the engine entering limp mode if they failed.

Maybe it helps combustion at very low throttle, which is a very lean mixture in a diesel.

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Thu 10 Nov 2016 21:07
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Hi thanks for replies but when I start car the spanner light comes on as it should then goes out but comes on for a second or two then stays out, put opcom on and came up with code p0380 glow plug error ,

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Thu 10 Nov 2016 21:53
vauxhall astra - vauxhall astra - vauxhall astra cdti - elekie&a/c doctor

One or more glow plugs may be faulty,but this may not be the cause of your suspect fuel consumption.What engine is this,1.7 or 1.9.?Have you had the glow plug system tested?

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Fri 11 Nov 2016 21:46
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Hi thanks for replies it is 1.9 cdti 120 has done 146000 miles does go OK , but I have started to put interior heater on and noticed fuel consumption dropped , have not tested glowplugs yet as they look a pig to get to

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Fri 11 Nov 2016 22:01
vauxhall astra - vauxhall astra - vauxhall astra cdti - RT

Even worse - the glowplugs on the Fiat JTD have a high risk of snapping during removal - necessitating cylinder head removal to rectify.

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Fri 11 Nov 2016 22:15
vauxhall astra - vauxhall astra - vauxhall astra cdti - elekie&a/c doctor

Yes,they are a pain to access.The 8valve engine is a lot worse than the 16valve engine.However,they can be tested from the relay connection that is located near the battery.

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Sun 13 Nov 2016 19:36
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Hi thanks for reply how can you test them at relay thanks

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Sun 13 Nov 2016 22:13
vauxhall astra - vauxhall astra - vauxhall astra cdti - elekie&a/c doctor

You are going to need some basic test kit.A digimultimeter and a high reading amp clamp,like this;www.ebay.co.uk/itm/Durite-Clip-On-Induction-Ammete...a

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Thu 17 Nov 2016 17:32
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Hi I might be able to get one of the meter does anybody know what wires to test or is it easier to take plugs out to test thanks

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Thu 17 Nov 2016 18:16
vauxhall astra - vauxhall astra - vauxhall astra cdti - madf

You can test plugs easily with a mutlumeter set to resistance.

Remove all leads to glowplugs. Keace plugged in.

One multimeter probe to screw on end of glowplu, other to hexagonal section to turn plug.

If plug is OK, reistance id 0.6 ohms. Usually a fialed plug has infinite resistance.

But my advice based on experience is that once one goes, the rest are likely go go soon.. I recommend replacing all. Ebay plus from correct maker are usually 50% cheaper than dealers.

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Thu 17 Nov 2016 19:52
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Thanks for reply will try and do this as will have to take egr valve off and fuel valve to get to the connections

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Thu 17 Nov 2016 21:33
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Hi with reference to my post iv also got a juddering problem, when I am in 5th or 6th gear and go to accelerate I get a juddering feels like engine is moving but if I keep accelerating it does go I thought it could be dmf but I can select gears OK , how would I know if dmf is on way out thanks

Edited by frogmarch on 17/11/2016 at 21:34

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Sat 26 Nov 2016 18:49
vauxhall astra - vauxhall astra - vauxhall astra cdti - frogmarch

Hi with reference to my juddering problem when I accelerate in fifth or sixth gear there is a juddering by it only happens at 1500 revs and disappears at around 2000 revs been told could be egr or injectors but I tried it today and there is a rattling when I change gear you mainly hear this when I change from second to third could this be related thanks

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