how do you drive a TDCi?
bluechair84
Posts: 4,352
Got my Ford Focus diesel! 1.6 (90ps). My daily drive is stuck behind a lorry on a long straight A-road doing between 40-50mph, very little breaking, just a long gentle cruise, only one hill. Yet I'm only getting 53mpg. I'm driving below the turbo at around 1400rpm. Might the engine perform better in a lower gear and high rev where the turbo is doing more work? Experience tells me to be in a high gear and low revs, but then I've only had non-turbo petrols before. I can't understand how low speed + high gear with no stop/go driving is giving me such low returns... Maybe my expectations are high but I have gotten 57mpg out of her on one journey but I can't remember what kind of driving I was doing...
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so
usual stuff first
injectors and rail ok, no bulging fuel hoses
exhaust sensor ok (loose connectors)
temp sensors ok? - ( a mate had all his temp sensors changed on a XJ6 another 5mpg...)
an oil change?, the better the oil.....
tyre presure, and type of tyres, grippy sports types will hurt, but tyres like pilots.....
excess weight in car?
and this sounds crazy, but its not something like the wheel spats or plastic sump guard is loose and bends down into the wind giving drag
complex
wheel drag - whilst driving and safe to do so, hands off the wheel and brake gently, does it pull to 1 side? or crabs?
reddex or millars additive, but have heard that shell vmax and the like does the same job, price per tank is comparable
no funny electrical traits, like the fan relay gets stuck when hot? that will put more strain on the engine, same for fuel pump, and check filter
air intake, is the maf ok?, is there any leaks or brakes in the air intake that can affect the cars consumption as can the idle valve
thermostat ok?
get a sports foam filter, paper 1's are not worth the time
diesel specialist garages can adjust the boost pressure on diesels, and rail pressure, they might not be in spec for the condition of the engine
inlet outlet manifold gasket leaks, spray wd40 on them whilst engine is running, smoke out the exhaust (inlet sucking in wd40), bubbles (outlet leaking)
oil seals in the turbo? (runaway diesel engine is the worst nightmare) - really dirty oil or high oil consumption
disconnect the air con pump (get a smaller fan belt that does not need the compressor)0 -
Wow, beast of a response. I'll go through the list at the weekend but as it's new to me (and at 94k miles) I want to send it in for a service. I used to do all my oil and filters but I've no longer got the wheel ramps. But from what I know, drives pretty straight, coasts with no excess decrease in speed (costs far longer than my 407 did). Nothing in the boot but some body armour.
But until I check all this over, am I right in assuming I don't need to be cruising at a high rev to make the most of the turbo?0 -
Your MPG isn't too bad but don't have the engine labouring as it isn't run at it's optimum then. I have the Mondeo tdci and assuming yours is similar with a 6 speed box then I try and keep the gears/speed as 3rd/30, 4th/40, 5th/50 and 6th above 50. This means that I'm usually changing up at around 2000rpm and changing down at around 1500rpm which keeps the engine in the highest torque band and ready to respond to increases in throttle.
Since you can get good MPG already then I don't think you have any mechanically wrong with the car. Don't change the air filter to a foam unless you have remapped the increased airflow doesn't make that much of a difference unless the car can take advantage. Tyres pressures make a difference but so does the weather with MPG rising on hotter days at the expense of less power and the reverse in cold weather.0 -
I think I'm using the same sort of gear speeds as you then, so maybe I don't need to worry about trying to use the turbo more for cruising. But I did expect better considering the long, slow and consistent commute I have each day...0
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You might want to think about replacing your glow plugs then. Modern diesels continue to use the glow plugs until the engine is warmed up to make it more efficient not just to help start it on cold mornings. They are about £36 a set so not expensive but they are a bit of a pain to fit as you will probably need to remove the inlet manifold to get to them but if your handy with a spanner it shouldn't take you more than an hour. I replaced mine a few weeks ago to find 3 out 4 had stopped working. With the new ones fitted my short, stop-start commute MPG has increased from 36 to 45mpg and fast motorway to 56mpg which is pretty impressive for a 2.2 lump.0
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That's a hell of an increase! I feel some youtube tutorials coming on...0
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53 mpg! I've had lots of diesel cars and have never achieved 53 mpg. I've had the odd 50 mpg, but usually around the late 40's. Sounds pretty good to me.0
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yeah... it's very good... but a mate who sits in traffic all day crossing London gets 55+ out of his 207! I'd say he must be light footed but he drives like a right nob. I have to remind him when he's up here that he doesn't need to drive like a Londoner - people will let him out and expect the same in return!
Anyway, if I can get it higher I'll be very happy
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Unless he lies.I don't do smileys.
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Parktools0 -
trip computer told me so.
But I have just realised I remembered it wrong :oops: - he got 55+ on the journey up the A1 last time I saw him. I'll have to enquire about what he gets on his commute. I know he's been very pleased with it though.0 -
Ah. There's your answer.bluechair84 wrote:yeah... it's very good... but a mate who sits in traffic all day crossing London gets 55+ out of his 207!
Pug diesel engines are just in a different class. I used to believe the VW hype, particularly from my father, who was a strong advocate of their diesel engines. But, after actually buying a diesel Golf, I have to say I'm quite dissapointed.
(DUH! just re-read, and realised you said Ford, but my brain only read the TDI bit :oops: Nevermind, I shall leave this anyway, like a kind of honesty box)0 -
YeehaaMcgee wrote:
Ah. There's your answer.bluechair84 wrote:yeah... it's very good... but a mate who sits in traffic all day crossing London gets 55+ out of his 207!
Pug diesel engines are just in a different class. I used to believe the VW hype, particularly from my father, who was a strong advocate of their diesel engines. But, after actually buying a diesel Golf, I have to say I'm quite dissapointed.
(DUH! just re-read, and realised you said Ford, but my brain only read the TDI bit :oops: Nevermind, I shall leave this anyway, like a kind of honesty box)
You might want to re re read it, the 55+ is refering to the Pugs journey on a long run, I doubt very much many cars can get 55+ in London-esq traffic.0 -
Probably not, but the Pug pool cars and vans we have at work just have the most phenomenal engines.0
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The OH has an '09 A3 diesel 1.9 done 100Kmiles in 3years and ave 57mpg, my '55 320d gives me no more than 41mpg on my x country commute but does return up to 50mpg on mway runs. I'd say getting 50+mpg is pretty good.0
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57 is what I hoped to get. I'm doing the oil and filters tomorrow, at some point I might check out the glowplugs as advised too. Hopefully these things will see it go up a little. I shall report back when I've new MPG averages for the work journey,0
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I don't understand hoes glowplugs could impact the fuel efficiency. Surely any fuel.ignition in the engine will provide far more heat than the plugs, so once it's running it should warm up nearly immediately.0
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YeehaaMcgee wrote:I don't understand hoes glowplugs could impact the fuel efficiency. Surely any fuel.ignition in the engine will provide far more heat than the plugs, so once it's running it should warm up nearly immediately.
During initial diesel engine warm up (which takes a while) the glow plugs are used a lot to help aid with efficiency, the colder it is the more diesel juice the injectors chuck in, so it helps warm it up to reduce chucking oodles in.
I'm not a mechanic but that's my understanding.0 -
Never trust a trip computer. Or a policeman.
The nice thing about the Ford diesels is that they don't seem to give great mpg when driven economically, but they also don't give bad mpg when driven uneconomically. I've been surprised how little driving style makes with mine, which is just as well really because I drive like a cock.Uncompromising extremist0 -
I still don't see it. Each explosion in the chamber should have a much greater warming effect than the glowplug ever could, surely? And even at tick-over there's approximately 125 of those explosions per cylinder per minute. (roughly 1000 rpm, 4 cylinders, one detonation every other revolution)Briggo wrote:YeehaaMcgee wrote:I don't understand hoes glowplugs could impact the fuel efficiency. Surely any fuel.ignition in the engine will provide far more heat than the plugs, so once it's running it should warm up nearly immediately.
During initial diesel engine warm up (which takes a while) the glow plugs are used a lot to help aid with efficiency, the colder it is the more diesel juice the injectors chuck in, so it helps warm it up to reduce chucking oodles in.
I'm not a mechanic but that's my understanding.0 -
Northwind wrote:Never trust a trip computer. Or a policeman.
My Pug was 2mpg too optimistic. I calculate it all from the receipts and clock now. I do however like cops, but the lady ones scare me. Must be a tough job but damn they've got faces like a slapped arse.
As for glowplugs? No idea. I'd love to restore an old Triumph but I know so little I'd end up with another car in spare parts by the time I'd finish.0 -
The general consensus for economy is to short-shift into a high-ish gear ASAP and try and stay there without braking but I've never tried it
The mighty Mondeo routinely shows 50-55 mpg on the computer but Road Trip pegs it at a more realistic 48-ish
A mate has a 90 bhp Eco Focus and it does about the same just knocking about. Think you would have to slipstream one of Stobart's finest at a steady 56mph to get much more.0 -
Mmm hypermiling. I read an article about a guy who got 99mpg out of his Fabie VRS by hugging the back of a lorry for 50miles. Personally, I find box vans to be better as they are often driven by people who've rented them, and will sit at 70-80 instead of 50. You can actually get somewhere and save fuel behind one of them0
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For me theres a million abms one things and ideas to try here, but are they all realistic, our going to make a hell of a difference over keeping to maintenance schedules and driving sensibly? I don't know. The only thing I do to get better economy is approach driving with a sensible attitude towards time and distance of my journey. For example, when I lived in wolverhampton and was travelling to Milford Haven I had two realistic routes, one took 3 hrs 45 on a clear run and used under quarter of a tank, the other was 75 miles further but motorways mostly so could be done in 3 hrs 30, but the higher speed and longer distance meant I used just over half a tank, so that 15 minutes extra was worth the 20-25 quid saving0
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YeehaaMcgee wrote:
I still don't see it. Each explosion in the chamber should have a much greater warming effect than the glowplug ever could, surely? And even at tick-over there's approximately 125 of those explosions per cylinder per minute. (roughly 1000 rpm, 4 cylinders, one detonation every other revolution)Briggo wrote:YeehaaMcgee wrote:I don't understand hoes glowplugs could impact the fuel efficiency. Surely any fuel.ignition in the engine will provide far more heat than the plugs, so once it's running it should warm up nearly immediately.
During initial diesel engine warm up (which takes a while) the glow plugs are used a lot to help aid with efficiency, the colder it is the more diesel juice the injectors chuck in, so it helps warm it up to reduce chucking oodles in.
I'm not a mechanic but that's my understanding.The glow plugs are located in the side of the cylinder head and aid engine starting and efficiency. The glow plugs and the glow plug indicator lamp are controlled by the powertrain control module (PCM).
The glow plugs preheat the combustion chambers, which aids cold starting. During the preheat stage, the PCM receives an engine temperature signal from the cylinder head temperature (CHT) sensor and this determines the preheat time. The lower the temperature, the longer the preheat time. There is a maximum preheat time of 8 seconds at -20°C or lower. At temperatures above 80°C there is no preheat phase.
Once the engine has started, the glow plugs enter an after-glow phase. The after-glow phase helps to improve idling and reduce hydrocarbon emissions through more efficient combustion just after starting. The after-glow phase only operates at engine speeds below 2500 RPM, above that, the after-glow phase is interrupted to increase the durability of the glow plugs. There is a maximum after-glow time of 30 seconds at -20°C or lower. At temperatures above 50°C there is no after-glow phase.
Technical stuff hopefully explains it for you.0 -
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The problems with diesels are they perform so poorly when cold, add to that cast iron engine blocks and they take a long while to warm up unlike petrol engines. Mine can take a good 20 minutes to warm up and after a very cold night even longer whilst the wife's petrol car will be warmed up within a few minutes. The glowplugs create the warm engine efficiency until it has actually warmed up properly.0
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That quote up there says the glowplugs are active for a max of 30 seconds. The engine running temperature (ie, the water temperatre), and the temperature inside the cylinders will be very different.CraigXXL wrote:The problems with diesels are they perform so poorly when cold, add to that cast iron engine blocks and they take a long while to warm up unlike petrol engines. Mine can take a good 20 minutes to warm up and after a very cold night even longer whilst the wife's petrol car will be warmed up within a few minutes. The glowplugs create the warm engine efficiency until it has actually warmed up properly.0
