Hi all
Ive recently purchased a 306 2.0 hdi W(2000) which is giving me approx. the same fuel consumption as my old 2.0 xsi , Im driving the car in the same way (economically) on the same route and im still getting about 130 miles from 20 litres. the mpg has remained the same during the past few months and has not deteriorated.
i took the car to a peugeot garage and they ran their diagnostics and found the following:
"Investigate excessive fuel consumption. Checked to find no fuel leaks, checked ecu memory to find multiple faults in system which may contribute to excessive fuel use. parts and prices listed below
air flow meter. £106.25
low pressure fuel pump. £220.83
accelerator pedal sensor. £93.94"
I dont like the fact they used the word MAY above, and various sources have told me that these diagnostic checks are not always 100% accurate, so im a bit wary on forking out so much money if im not certain its going to fix the problem.
1. Has anyone out there had something simular or does anyone know if changing any or all the above would solve the problem?
2. Does anyone know where i could find these components, ive read that the air flow meter and accelerator pedal sensor are in the electrical control system, is that the box which holds the ECU?
3. Where can i obtain these parts?
Thanks in advance
Edited by Pugugly {P} on 26/12/2007 at 22:19
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This is why I like my XM with an old fashioned mechanical fuel pump! Assuming yours is not an auto, you should be getting around 40-50 mpg so something is obviously wrong. Is it smoking at all, particularly at full throttle? this would indicate overfueling or incorrect timing, all controlled by the ECU or injector fault/s. I dont know very much about common rail engines and most of that I have learnt on this forum from 'Screwloose' I'm sure he will be along shortly.
Peter.N.
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ap
That's only 30mpg. Are you sure? You really need to do a brim-to-brim check on a full tankful to get an accurate figure. It should be pouring black smoke, unless there's something causing a drag somewhere. Brakes etc.
Of the listed faults, only the MAF [airflow meter] could cause high consumption. It's very uncommon on HDi's, but very plausible if an non-genuine [flea-bay] fake one has been fitted.
Knowing the exact codes would help a lot; low-pressure pump failure is common, but doesn't usually give a code, as are APP sensor [on the end of the throttle cable] codes that won't clear whatever you do.
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Hi, thanks for your response
Yes, pretty sure its about 30 mpg, slightly more if im on the motorway, i re-fuel every few days, as soon as the reserve light indicator comes on, i add 20 litres and reset the counter
1. Is there any way i can get the codes?
2. Any idea where i could find an air flow meter and an accelerator pedal sensor?
3. Is there a low pressure fuel pump, or, is there low pressure in the fuel pump?
4. Where can i find these, are they easy to locate and change?
I might just try and get these changed, so they can be eliminated, and hope it fixes the problem.
Thanks in advance guys
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ap
That's not a very accurate way to check consumption; it's over a relatively small quantity with a temperamental indicator. Try a brim-to-brim check for a definitive figure.
Don't change anything yet - you'd be throwing money away. If those codes were not current and just stored [and there's no mention of the MIL light being on?] then they could have been there for a very long time and mean nothing. Codes are never a certain fault anyway - just a guide.
There is a low-pressure pump in the tank - but the ECU has no monitoring system on it's circuit. There is a high-pressure sensor and that can indeed set a under-pressure code - a serious matter - that's why knowing the exact code numbers they found is vital.
Ask the garage for the exact codes.
MAF sensor is a black plastic tube in the air-duct just after the air filter.
The APP sensor is a black block on the end of the throttle cable just above the radiator.
The low-pressure pump is inside the fuel tank.
Only the MAF can affect MPG - and, usually, only if it's a cheap fake. [Thousands around everywhere.] False APP codes are very common - almost normal - and are always ignored.
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Hi there screwloose
i took your advice and went back to the garage to ask for the error codes, i managed to get a fault record of the test they performed, ive copied the main bit of the sheet word for word as follows:
Diesel
RHY BOSCH EDC15C2
Fault reading.
Engine ECU
EDC15C2
Permanent fault. Flow sensor signal. Open circuit or short circuit to earth.
Permanent fault. Flow sensor signal. Coherence: Air flow not sufficient.
Intermittant fault. Clutch switch signal . Cosistency with vihicle speed.
Intermittant fault. EGR circuit. Air flow lower than recommended.
Intermittant fault. Diesel high pressure monitoring function. Lack of pressure( leak).
Intermittant fault. Accelerator pedal signal 2. Coherence with aacelerator pedal signal 1.
Intermittant fault. Fuel low pressure pump supply. Coherence when the engine switched off.
It seems from this the car definatley requires an air flow sensor (i have contacted a local parts dealer and i can get a SiemensVDO for £61.99), they are showing as permanent faults, any help you can give me from this will be much appreciated
Thanks in advance
Edited by ap306 on 29/12/2007 at 14:30
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ap
Thanks for the info; interesting....
The MAF monitors the EGR flow and shares an earth the APP sensor. I'd want to confirm that's sound, or do the official modification, before spending on a new MAF.
[If it's not from a dealer or a VDO agent it stands a high chance of being a useless counterfeit - you'd be better off with a secondhand one]
The low pressure pump code [P0230?] suggests a relay issue and might be the root of the quite common [P1112] high pressure code.
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I had a 53 406 2.0HDi 90 estate, it only ever did 34mpg :-( I put it down to the high weight of the car coupled with the climate control being permanently on. Very gutless it was, too. My Octavia SDi estate used to do between 44-56mpg on the same work.
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I am now getting about 190 miles from 20 litres of diesel via general driving (no motorway) which is about 42mpg.
I still get the same (about 190 miles from 20 litres) when driving nothing but motorway (about 70mph average). I have compared this several times and re-fueled from a completely empty tank. According to the peugeot manual and parkers i should be getting 64mpg motorway, and 54mpg mixed driving. But no matter where i drive i always get about 42mpg.
A few months ago i took car to peugeot garage for diagnostic report, please see the above for diagnostic results.
Could something like the fuel pump cause this problem?
Thanks once again in advance
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>>The MAF monitors the EGR flow and shares an earth the APP sensor. I'd want to confirm that's sound, or do the official modification, before spending on a new MAF.
Hi Screwloose,
Please elaborate on the mod. Is it possible to identify a fake MAF sensor? Is there any other info knocking about on fakes?
Sorry for all the questions.
Thanks.
Steve.
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Steve
All the early HDi's were plagued with constant, false, accelerator pedal position sensor codes.
As the MAF and the APP sensor have a shared return cable to the ECU; the official mod was to cut the two MAF earths off from that circuit and extend them to a good earth. The idea was to stop any variation and noise in the return current flow from the MAF upsetting the APP sensor's reading - it rarely worked.
Fake MAF sensors are indestinguishable from the real thing - until you fit them. I had a case ten days ago where a garage had fitted three from a big chain of factors; all fake - all faulty.
MAFs have to be bought from the dealers; it's now the only way to be sure of what you're getting. Prices are often lower than the e-bay fakes.
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Hi Screwloose.
Thanks for the info.
I asked because my C5 doesn't seem very economical. It's averaging around the mid 30s which although not rigorously checked does seem about right for what I'm putting in the tank. The fuel computer often shows MPG in the high 20s low 30s (instantaneous reading) when average driving, if I hammer it it goes down to the low teens, tickling it on the flat on the motorway I can see mid 40s. The only ECU code was coolant related (not sure of actual code though) and it's just had a oil and filters service. It doesn't seem powerful but cruises and picks up speed OK.
Do you think the MAF could be faulty or a fake?
Thanks.
Steve.
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Steve
Year, usage and engine code?
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My HDi 90 manages 38-39 on average, mostly on country roads and I don't drive slowly. On motorways gets a good return of mid 40's to 50 when crusing around 60mph. 70mph seems to be the magic figure though, above and fuel consumption is not very good, below and its acceptable.
Do you do a lot of town driving?
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Hi,
It's a 53 plate, engine code RHZ (DW10 ATED ?). I mainly drive non rush hour with very little standing traffic on dual carridgeways so would that be called mixed driving?
I can't say it's eager to rev much either compared to my 2.5 TD XM.
Thanks.
Steve.
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Hi Screwloose,
Was that the information you needed?
Thanks.
Steve.
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Yes; but it provides few clues. There's no FAP fitted; so that's ruled out and you aren't doing a lot of urban miles.
Brakes not seized?
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Hi,
I don't think so, it coasts OK and moves easily with the handbrake off on a slight slope.
What are the symptoms of fake MAF sensors please?
Thanks.
Steve.
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