Engine & Gearbox Redlining - worth it or farce?

Discussion in '3rd Generation (2006-2012)' started by agadza, Wednesday 4th Nov, 2015.

  1. agadza Club Member ★ ☆ ☆ ☆ ☆

    United Kingdom Agadza London
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    Hello All,
    As some of you might know form my other thread, I have been driving my I-CDTI mostly in town and like a "petrol driver".
    I am only getting 33 MPG, which I have been told is very poor and likely the result of my driving style. I read on another thread in this forum about someone resolving a similar problem by "redlining".
    Questions: Is this advisable to do? Or should I just buy an injector cleaner?
    What is the correct way to do this?
    Thanks in advance.
     
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  2. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    First and foremost is to make sure the engine is well serviced. All the fluids and filters changed at correct intervals. A clean EGR system also seems to assist attain good figures on a diesel.

    Engine health aside, your driving style has another big impact on fuel economy, you want to drive smoothly and progressively. Plan well ahead, minimise braking as much as possible. In slow moving traffic leave a gap and keep the car rolling as much as possibly, opposed to lots of stoping/starting.

    I let the true diesel experts advice you further.
     
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  3. agadza Club Member ★ ☆ ☆ ☆ ☆

    United Kingdom Agadza London
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    Talking about service intervals, the maintenance book seems to indicate 12,500miles between each service, at whihc I assume the oil changes happen. Some posters on here say 5 - 6000 miles for oil changes. Who is right?
     
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  4. jimjams Expert Advisor ★ ★ ★ ★ ★

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    it depends on several factors, but generally the engine oil on a diesel gets dirtier more quickly than on a petrol, because the EGR brings particulates back into the cylinders (not the intention of the EGR, but it does). Those particulates get into the engine oil, so many people recommend changing the oil more frequently (they also recommend it for the petrols too, but for different reasons)

    On the subject of MPG for a diesel engined car, they take a lot longer to reach operating temperature, and a cold engine gives poor MPG.
     
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  5. Kash Club Member ★ ☆ ☆ ☆ ☆

    United Kingdom Kash Nelson
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    Are you driving long periods locally or just short journeys? As mentioned earlier diesels take much longer to warm up. You've also got to remember a CR-V is a heavy car too.
     
  6. Zebster Expert Advisor ★ ★ ★ ★ ★

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    You didn't mention poor MPG in your other thread, nor have you mentioned the issue of stalling in third gear here. Poor MPG, coupled with an unwillingness to accelerate, indicates a problem. Possibly the EGR valve isn't closing properly, but hard to be sure. In the other thread I suggested HDS boost pressure tests, but the range of HDS tests includes a test of the EGR. Injector cleaner won't fix these problems.
     
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  7. jimjams Expert Advisor ★ ★ ★ ★ ★

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    @Zebster IIRC the MPG of your diesel Accords is lower than that of other diesel Accords, so is there a serious problem with the engine in your car ?
     
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  8. Zebster Expert Advisor ★ ★ ★ ★ ★

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    I usually get around 43 MPG. I haven't done an accurate survey of other diesel Accord PFL Tourers, but while I reckon that's acceptable, I know that many claim higher. Possibly they drive slower or don't cart so much junk around or undertake longer journeys, etc?

    Do you really think that 33 MPG is acceptable, or are you now trapped by your other arguments into convincing Agadza that his problems are all due to not revving his diesel like a petrol engine? LOL.

    BTW - have never referred to these problems as 'serious'. There are several easy-to-fix issues that can affect I-CTDI economy and performance.
     
    Last edited: Thursday 5th Nov, 2015
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  9. Zebster Expert Advisor ★ ★ ★ ★ ★

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    Perhaps these threads should be merged?
     
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  10. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    I think it'll get confusing now if I merge them ??
     
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  11. agadza Club Member ★ ☆ ☆ ☆ ☆

    United Kingdom Agadza London
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    On average, I do 20 miles some four days a week. I only travel "long Journeys" about once every three months.
    I think that would qualify as "urban" driving?
     
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  12. jimjams Expert Advisor ★ ★ ★ ★ ★

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    ^ is that 80 miles in total per week (i.e. 20 miles each of 4 days), or is it 20 miles in total per week

    either way, it's a very low figure for a diesel, and might well explain the low MPG figure
     
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  13. Ichiban Founder Staff Team

    England CJ Leeds
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    I used to get 58-62 MPG on my milk float so you guys only get 40!! :gotcha:
     
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  14. agadza Club Member ★ ☆ ☆ ☆ ☆

    United Kingdom Agadza London
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    80 miles a week, all done in town traffic conditions.
     
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  15. Kash Club Member ★ ☆ ☆ ☆ ☆

    United Kingdom Kash Nelson
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    I'd say that's acceptable, I think it would be unrealistic to expect 40s in local town driving in a car as big
     
  16. Zebster Expert Advisor ★ ★ ★ ★ ★

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    The weight difference between an Accord Tourer and CR-V is negligible. Depending on the exact specifications, the CR-V may be lighter.
     
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  17. jimjams Expert Advisor ★ ★ ★ ★ ★

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    I doubt if the engine gets warmed up much, if it had a DPF you would also end up having the DPF light on quite often.
     
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  18. Kash Club Member ★ ☆ ☆ ☆ ☆

    United Kingdom Kash Nelson
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    Jeez didn't realise the cars had so much weight! For local, short town driving surely expecting 40 odd MPG is unrealistic?
     
  19. chris2982 Premium Member Club Supporter

    United Kingdom Chris Rowlands Gill
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    just found this:

    "The Italian tune-up - at least in a diesel [although it applies to a gas car too - Ed] consists of taking a SOUND car out and maximally accelerating from stop or slow speed to some high speed OR driving at near full RPM with a heavy load (up long hill) for minutes at a time. The idea is to get maximal air and fuel flowing through the engine to develop near maximum heat. This will burn and eject residual carbon that has collected in the engine. Following such a regimen the idle is usually smoother and the amount of black smoke at full throttle should be reduced. This occasionally does not happen the 1st time and the idle might get rougher or a pronounced knock could occur. This is usually because some carbon has been "rearranged" but the prechamber environment isn't appropriate for smooth combustion. Further TREATMENT will clear this up as more carbon is burned up, but it is a little scary the 1st time it happens to YOU and your car!

    A few full throttle accelerations a week will usually keep most CLEAN engines cleaned out pretty well. More prolonged "treatment" is usually required for a car that has had a LOT of city driving. Just a long highway trip (50+ miles) with several two-three minute full throttle periods (long 6-8% grades are GREAT) will clean out an awful lot of carbon and crud that's build up, but with a really "city bound car" it may may take more than just a few sessions to really get it all out. My weekly 250 mile trips from Pittsburgh to Washington DC and back over the last 7 years have given me a chance to really examine the "Italian tune-up" and the concept of "flailing the heck out of the MB diesel engine" or at least running it at near full throttle/top speed for a long period of time.

    I referred to a "SOUND" car. To me that means a car that NO serious mechanical problems. The chain stretch should be below 5 degrees or so, the valves should be properly adjusted, the air and fuel filters should be verifiably clean, and there should be clean and it would probably be best if the injection pump timing is known to be pretty close to correct (within a couple of degrees). The cars/engines I presently own, have THRIVED on this regimen. Idle smooths out, smoking diminishes, and fuel and oil consumption goes down. I can't promise that on an engine that's worn out, but nobody else can either ;-)"
     
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  20. Zebster Expert Advisor ★ ★ ★ ★ ★

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    But it turns out that this isn't actually urban driving. And 20 miles isn't an unusually short journey.
     
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