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Nov 10, 2019 18:49:37 GMT
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Evening all Car is actually a p38 rr, but 2.5 diesel Fuel consumption never that good, but is steadily getting worse Fuel computer figures used to hover around the 29mpg mark, but is on a steady downward curve, now registering 27.4, even on a 350 mile trip today, mostly A roads/motorways but all under 3k rpm It has now done 211k, and smokes under load, but ‘they all do that sir’ An I expecting too much, or is the engine dying, or the electronics lying, in a p38? Surely not!😳 Doesn't feel any different to drive, never been exactly land speed material anyway Any ideas? TIA
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Nov 10, 2019 19:07:23 GMT
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Smoke colour?
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Needs a bigger hammer mate.......
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Nov 10, 2019 19:34:00 GMT
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Blue:blackish Does use oil
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Nov 10, 2019 19:43:11 GMT
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Turbo on the way out probably, won't help with efficiency but it's never going to be an efficient car to run.
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Nov 10, 2019 22:30:37 GMT
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Injector nozzles?
Could even try a dose or two of injector cleaner. Works on my old 5 pot Audi which is similar technology. Also, some fuels are better than others and I find that the winter blend reduces mpg a little
Nick
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1967 Triumph Vitesse convertible (old friend) 1996 Audi A6 2.5 TDI Avant (still durability testing) 1972 GT6 Mk3 (Restored after loong rest & getting the hang of being a car again)
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tristanh
Part of things
Routinely bewildered
Posts: 990
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Nov 10, 2019 22:43:25 GMT
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Cold weather? My 1.9 tdi was noticeably worse on fuel in winter.
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Whether you believe you can, or you cannot, you're probably right.
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check tyre pressures, grease the props, get an ENDTuning chip.
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Its supposed to be a hack until i get the daily rrc back up and running, its always smoked, in fact under severe load the road behind disappears! Think ill try the injector cleaner first because (a) its cheap and (b) I'm basically a lazy sod Thanks for help all
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Thats still pretty good consumption from a 2.5d p38...amazed you were getting near 30mpg. here is my hit list in order of things to check with the m51 bmw engine
1. Fuel filters- if blocked it will make the performance poor and smoke under load 2. Intercooler Hoses- If split or collapsing under load will make noteable smoke and not perform as well 3. EGR system...clean EGR valve or blank off alltogether 4. Injectors..leak off tests 5. Turbo-piece of cake to change on these engines 6. Run a 60/40 mix of veg of diesel/vegoil through it...cleaned my m51 lump right out and it ran sweet as a nut and much smoother..be aware you will probably need to change filters after a few hundered miles if the fuel system is full of curse word.
m51 is a really simple engine and a doddle to work on
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Last Edit: Nov 11, 2019 8:08:16 GMT by grahamk
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ChasR
RR Helper
motivation
Posts: 10,191
Club RR Member Number: 170
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Nov 11, 2019 18:25:39 GMT
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My dad 325tds would only really crack 40MPG on a motorway run for what it is worth.
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Last Edit: Nov 11, 2019 18:29:06 GMT by ChasR
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Nov 11, 2019 18:41:21 GMT
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As well as all the above, it may be something as simple as the brakes dragging or the tyre pressures being a bit low. Checking for overly warm wheels after a run or rusty areas on the discs offer clues without stripping the vehicle. Good luck
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Nov 11, 2019 19:49:09 GMT
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Turbo oil seal a likely culprit. If you can get a finger in (phnaar) check the radial play on the turbine shaft, also have a look in the intercooler pipework for oil deposits.
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Needs a bigger hammer mate.......
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time
Part of things
Posts: 152
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Nov 17, 2019 21:08:17 GMT
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What year is it ? The later ones had an egr that was prone to sticking (Although its easily deleted) Does it start easy when hot ? If it doesn’t your timing is out which will effect economy
There’s also a vacuum pipe under the inlet manifold that Can partially collapse causing smoke and poor fuel economy
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Nov 18, 2019 12:41:44 GMT
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Its a 1999, on an ‘s’ plate, I've slung a bottle of injector cleaner in it, will await results & report back its got the hot start mod, needs to carry out its self check, but then usually fires up reasonably well ]Thanks for ideas & assistance all
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Nov 19, 2019 18:44:43 GMT
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Right, i am able to report that it now uses no diesel at all This may be due to the fact that this morning the engine seized solid, fortunately only a couple of miles from home Anybody want a REALLY fuel efficient P38?😁
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Nov 19, 2019 22:23:33 GMT
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excuse to fit the 335D engine
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Right, i am able to report that it now uses no diesel at all This may be due to the fact that this morning the engine seized solid, fortunately only a couple of miles from home Anybody want a REALLY fuel efficient P38?😁 Erm, what "injector cleaner" did you use, for future reference??
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It was the lucas stuff, to be fair i don't think thats anything to do with it, the engine started making bearing style noises, although no dash lights came on. I was driving up the side of a river known as the ‘16 foot’ locally, so i was taking it easy because i didn't want to go for a swim, but then the clutch pedal started moving when the throttle was pressed, so the crank must have had HUGE endfloat, and it just died with no warning, and refused to turn over again, so it deffo bottom end related Back to my mk3 escort cabrio then, until the RRC is done
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Nov 20, 2019 19:12:02 GMT
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Unusual failure....... Somewhat disappointing.
Maybe it’s been chomping on itself for a while and that’s been affecting the mpg......
I use the Toolstation injector cleaner and so far my engine is still turning
Nick
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1967 Triumph Vitesse convertible (old friend) 1996 Audi A6 2.5 TDI Avant (still durability testing) 1972 GT6 Mk3 (Restored after loong rest & getting the hang of being a car again)
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gtste
Part of things
Posts: 75
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Nov 20, 2019 20:01:13 GMT
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Let me know if you're gonna sell it! Been after a P38 for a while.
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