Fuel Consumtion

[Bry]

Have just bought a 07 vtx/TD/est with Hundred and 2 thousand on the clock with fully stamped service history,last ser 101,110 re/ Arnold Clark in Stirling rear pads were down to the metal and the dip bulbs had just been pushed in no clips in use,had to change the lamps for French any way , pain to fit as the whole bumper has to be removed, allso why do you need to carry spare bulbs as you cant replace them on the drivers side with out removing the bumper again and the battery has to come out for the passenger side, a real pain if you lose your lights at night have now sorted this out and it runs well except I only gets 44/to/47 mpg on a run using cruise control on m/w,or just using my foot, am I expecting to much for a 1600 engine, I can get forty from my old 2.2excl and was hoping to get at least 50 plus from the new one I Am very light footed and can get60mpg from my 90,000mile scenic

[Paddy77]

Have just bought a 07 vtx/TD/est with Hundred and 2 thousand on the clock with fully stamped service history,last ser 101,110 re/ Arnold Clark in Stirling rear pads were down to the metal and the dip bulbs had just been pushed in no clips in use,had to change the lamps for French any way , pain to fit as the whole bumper has to be removed, allso why do you need to carry spare bulbs as you cant replace them on the drivers side with out removing the bumper again and the battery has to come out for the passenger side, a real pain if you lose your lights at night have now sorted this out and it runs well except I only gets 44/to/47 mpg on a run using cruise control on m/w,or just using my foot, am I expecting to much for a 1600 engine, I can get forty from my old 2.2excl and was hoping to get at least 50 plus from the new one I Am very light footed and can get60mpg from my 90,000mile scenic

 

Hi I think your mpg is ok as the c5 it a big car for a 1.6 & keep on 6000 miles oil change with that engine as there know to eat turbos but are ok if the oil is changed on time.

[Johndouglas]

What speed have you got set on your cruise? Mine is a 2ltr engine but my long-drive fuel consumption varies according to my average speed. If I'm set at 70, I'll get 46 or so. Set it at 65 and it'll be nearer 49. Be boring and set it at 55mph and it'll be doing 55mpg. And yes - I've always thought it daft that a spare set of bulbs have to carried in the car when it's sutch a pain to change them.

[paul.h]

For the 1.6 hdi estate the official figures are 40.9 / 61.4 / 51.4 mpg urban / extra urban / combined compared to 36.2 / 56.5 / 47.1 for the 2.0 hdi estate. So maybe driving slowly on a motorway (up to 65 mph ?) and not into a wind or up hills or accelerating quickly and going up hills let the speed drop a bit, you may get 50 ish. 50 mph roadworks are good for economy as long as there is not a slow queue in to them. Reset the trip meter just before a trip on the motorway and see how well you can do. Also in colder weather the fuel use will be a bit more than in summer.

 

If you do lose your lights at night try the front fog lights as a temporary measure.

[DaveHerns]

On the topic of fuel consumption increasing when it's cold . how long should a diesel C5 take to reach normal running temperature ? Mine's taking 3 miles ,wonder if it needs a new thermostat ?

[paul.h]

2 or 3 miles or about 5 minutes is probably about right for most cars I have had (petrol and diesel). When the thermostat has needed replacing, they have not got up to temperature or only if stationary but when moving again the temp has fallen, also the cabin heater has not been that warm. Some temp gauges though may not be a true reflection of the actual temperature, our C3 has bars which light up and each bar can cover 5 to 10°C. A code reader with live data is better to see the indicated temperature provided the sensor is ok.

[DaveHerns]

Mine's probably OK in that case as it gets up to halfway(ish) on the gauge and stays there

[393]

I have a 2001 C5 2.2 Exclusive est auto with 68,000 on the clock, I've just had the injectors sorted at the cost of €650 (I'm in Spain) although I think he just cleaned them and put them back in, but that's another story, the thing is, The very best fuel MPG that I've ever had is 31.4 mpg, the car has been de-fapped and starts and drives well, however, it is the only C5 I've ever had/driven, Looking under the bonnet today I noticed that when revved up the turbo pipe doubles in size, is this normal?

I like the car and it all works except for the rear window not opening which isn't a problem, any ideas what my next move should be re the mpg please.

I would add that when I bought the car I did so long distance, I am in Spain So a friend in the UK bought the car, now the ad said how good the car was on fuel, well, before I picked the car up in the UK I had it serviced, and in doing so had a new cambelt fitted, if the new belt wasn't fitted exactly right, would that affect the fuel mpg and if so how can I check?

 

Thanks........Jeff

[Randombloke]

I have a 2001 C5 2.2 Exclusive est auto with 68,000 on the clock, The very best fuel MPG that I've ever had is 31.4 mpg,

 

Early 2.2s are not good for fuel economy. The auto is worse.

 

I have a friend with a well maintained 2.2 auto, same age as yours. On long runs with no town driving he gets 40-41 mpg.

 

Biggest problem IME with the early C5s is binding brakes. Clean, and carefully copper ease the front pads + their carriers, and make sure anti rattle springs are not too strong.

 

I got sick of doing this every 6 months on mine, and have replaced the front callipers to find I now get the best fuel economy I ever have.

 

Long runs at 70 can get up to 46 mpg, at French motorway speeds (80) still 43.5.

 

Mine is a 5 speed, not 6 speed manual.

 

Also, make 100% sure that the tyres are correctly inflated.

[393]

Thanks Randombloke, I spoke the an English guy with the same car as mine, he said that he got 40/45 running about and on long runs 55/60, mine stays the same no matter what I do, perhaps I should buy his car..lol

Any ideas on the turbo pipe doubling in size when revved?? or how to check that the cam belt is on right??

[mechcanico lee]

The turbo pipe will expand when it goes under boost conditions i dont think this is your issue , i would say if the cam timing is out you would get cam/crank synchronisation codes .....have you got any fault codes ??

 

You need to maake sure your egr valve is operating properly and it is seating this can affect fuel mpg quite alot, also sometimes the vaccum solenoid can pull the egr open when it shouldnt, on the 2.2 hdi they have swirl flaps , make sure the actuator rod hasent broke off where it fastens to the butterflys on the manifold .

 

I have a peugeot 607 2.2 hdi 2003 ,i have just got a software package to do dpf deletion and power up grades , i have removed dpf , carried out egr deletion (ball bearing in vac pipe ) and power up grade to 165 bhp ....the car has never been so good my average mpg as gone up to 36mpg from 29 mpg and on the motorway it is doing 47 mpg at steady 75mph up from 41mpg and it pulls like a good un .

 

You say you have had it de fapped ....so you had the software file re written aswell ?? does your car black smoke alot ? does it pull well or is it under powered ? both can be signs of egr leak .

[ukwide]

Hi, I have the 07 2.2hdi VTX+ 6 speed auto with 59k on the clock (most of it m'way mileage) and I've found the type of fuel makes a big difference. Sainsburys City Diesel only gives me 38-39 mpg no matter how I drive, but Shell normal diesel gives me 47+mpg even cruising at 70-75 mph. I have tried it a couple of times all with the same results, so saving 1p a litre at Sainsburys is a big false economy for me...............

[paul.h]

On an old brochure from 2002, it gives the mark 1 C5 2.2 hdi estate auto fuel figures as urban 28.5 mpg, extra urban 52.3 mpg, combined 39.8 mpg. The mark 2 C5 2.2 hdi 173 hp, auto is 27.4/50.4/38.7 mpg urban/extra urban/combined so if 393 has a similar driving style/conditions to ukwide, then he should get 1 or 2 mpg better for the mark 1 C5. If not done already, it is worthwhile resetting the trip computer before a run by holding in the button on the end of the wiper stalk and doing long runs and urban runs to see how they compare.

 

I would check if the turbo pipe has gone soft allowing it to balloon up but this is probably not affecting the fuel consumption unless the turbo pressure is too high which could put the car in limp mode.

[393]

Thanks for all your help, today I took the EGR pipe off and blocked it, well, what a change, alot more umph and would you believe it, it has gone from 31.4 mpg to 45.5 mpg, mind you that was at a steady 55 mph, do I now clean/replace the EGR valve or just leave it as it is?

[mechcanico lee]

Leave it blanked , depends what software level or injection system is fitted that denotes if it will flag man. light on or just be logged in ecm as a stored code .

How have you blanked it ?? with a plate or ball bearing in vac pipe ?

[393]

It hasn't shown and faults and i've blocked it with a bolt, would the car not be better with the EGR valve cleaned and connected?

[mechcanico lee]

Better without it,mixing hot gases into a cooled inlet manifold makes "the black death " if its doesnt flag the man light leave it blanked,engine oil will say cleaner and not deteriorate as soon .

[qman3428]

I have been running a mitsubishi with a blanking plate for the last 4 years, best £5 I ever spent.

[TheGoose]

Early 2.2s are not good for fuel economy. The auto is worse.

 

I have a friend with a well maintained 2.2 auto, same age as yours. On long runs with no town driving he gets 40-41 mpg.

 

Biggest problem IME with the early C5s is binding brakes. Clean, and carefully copper ease the front pads + their carriers, and make sure anti rattle springs are not too strong.

 

I got sick of doing this every 6 months on mine, and have replaced the front callipers to find I now get the best fuel economy I ever have.

 

Long runs at 70 can get up to 46 mpg, at French motorway speeds (80) still 43.5.

 

Mine is a 5 speed, not 6 speed manual.

 

Also, make 100% sure that the tyres are correctly inflated.

 

 

I have a 2001 C5 Exclusive SX Hatch 2.2Hdi (Not Re-Mapped yet) 5 speed manual. 105K on clock. De-Fapped. Tyres inflated to about 34 psi on front, and the same on the rears. On motorways 70mph, lets say reasonably flat, not much wind, I will get between 50-55mpg. That's when I am watching the instant mpg calculation, if I reset and watch the average, it falls exactly the same. I have no drag on my front brakes either.

 

I know that my mother-in-law's previous car was a brand new C3 1.6 Auto Petrol engine, and this was crap on fuel! I mean even on a run, all you would get was high 30's mpg and that's it. If you were going downhill on the motorway you would get into the 40's, but only in that situation.

 

 

Personally, I don't think that auto box's are very good on fuel on any car, (compared to the manual versions) there heavy! With lots of stuff going on in them, like multiple clutch's etc etc. Which I think doesn't help with fuel consumption, Auto box's are..... at the end of the day for people who don't like the manual-ness of changing gear all the time. LOL but this adds extra complicated technology, and Weight!. Correct me IF i'm wrong.

 

I go manual gearbox any day, but it's all personal taste!

 

Can anyone help me blank my EGR aswell? As i am familiar with what it does and how it does crap up your engine, personally, I don't like the sound of hot crankcase emissions being fed back into the cool air inlet.

 

 

 

Happy days!

 

Mike

[qman3428]

If its working put a ball bearing in the vacumm pipe so it doesn't open. If its not working use a blanking plate between the EGR and the manifold. The second is a better solution but the plate needs to be at least 3mm thick or it can burn through causing damage to the engine.

[TheGoose]

I have got the blanking plate on order from Ebay. I will also aquire a ball bearing from somewhere too.

 

Do you know if the butterfly valves on the air intake can be removed or disabled aswell? Cus im concerned that with these flapping about all the time during the rev. range then this could be restricting the intake pressure, and maybe contributing to poorer running, mpg etc. The Butterfly valves work with the EGR system, aiding this system to work with ANY rev range. By reducing air intake pressure at various engine RPM's. Without these Butterfly valves, the EGR system will only work with low/Intermediate RPM, and will not work at all with Higher RPM's

 

Basically how I understand this EGR valve, is that the EGR itself (if working correctly) doesn't contribute to the oil build up of the air intake, and tract + valves etc. etc. This is mainly caused by the Crankcase breather and a bit from the Turbo unit. Which is normal. However, combine this oil with the EGR's heated carbonized air, resaults in this sticking to the oil build up from the Crankcase Breather. and gets baked on, causing your engine to coke up badly over a period of between 40k-60k. AND this also contributes to the blocking up of the Diesel Particulate Filter aswell, as all the crap which gets pumped into the air intake gets burned by the engine, and deposited into the DPF and over time can lead to the DPF problem, which so many of us have/or had. I have learned this from various other forums from around the net. The problem with EGR and Crankcase Breathers relate to both Petrol and Diesel engines. Except for the DPF which are only fitted to more modern diesel engines.

 

Have a read through this forum thread specifically talking about the 2.2 Hdi Engine, and the belief that the 2.2 Hdi was a PSA experiment in trying to increase the rev range over which it was possible to get recycling of the exhaust gasses beyond the 2K range of previous generations. To do this they use modulation of the Turbo the EGR valve and the Air admittance valve plus the swirl valves.

NB This may have been a requirement of EURO4 I havn't studied the Euro3/4/5 requirements.

 

Did they get it right? Well the experience of most owners would appear to be no!..

 

http://www.frenchcarforum.co.uk/forum/viewtopic.php?f=3&t=34544

 

Also check out this YouTube video on what this mechanic thinks about EGR!

 

I believe that if you read through this information, and watch this video you will be able to make up your own mind about the EGR systems found on lots of engines, as I know that alot of people have mixed opinions regarding this. I found this info. VERY helpful, I have made my own mind up now.

 

 

Thanks

 

Mike

[qman3428]

You dont need both as the blanking plate will stop the gas irrespective of wether the ERG is open or not. You can also forget the butterfly valve as it will make no difference. The only time you need to do more work is if you get warning lights having fitted the blanking plate. If there is no light there is no problem :)

The EGR valve was a california insiped attempt at reducing pollution, funny Citroen fitted them as they dont sell cars there.

[Randombloke]

Good and bad news.

 

On the older 2.2 where the EGR valve may be tired or badly designed or not working properly or worst, stuck open, the simple blanking plate you get on eBay takes 5 minutes to fit if you are an average car twiddler and seconds if you are a real mechanic. It improves response at light throttle openings, and fuel economy across the rev range and driving conditions. Fitting involves slackening off the two bolts that hold the end of the EGR pipe into the intake manifold, slipping the plate in and retightening.

 

On a newer 2.0 with the 20k service intervals it seems to reduce the economy slightly, even though throttle response seems slightly better.

 

If you have an older 2.2 with motorway economy below 43 mpg then try it, if it's better than that don't fit what isn't broken. My improvement was from about 42mpg on French motorways at 120kph to 46/47mpg at 125kph.

 

For £3 roughly it's a simple and inexpensive thing if you end up having to throw it away. If it works it will be the cheapest fix you have ever done, as one of the previous posters has said.

 

Just make sure you do the bolts up sensibly tight.