phelpsa
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| posted on 2/2/06 at 11:26 AM |
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Diesel Volvo Problems
Our 2002 Volvo V70 D5 is very lumpy in the cold and has dropped about 4-5 mpg over the last few weeks. It went to the dealer who said 'must be
the injectors £1500 please'. Dad told him where to put his injectors and booked it in with the local diesel specialist. They tested the
injectors and they're fine, so they went to do a compression test. Unfortunately the engine has abnormally small glow plugs so they've had
to order an adaptor, which is on its way.
Does anyone have any idea what could be wrong. I thought it could just be gunked up injectors as it is at about 70000 miles of mostly motorway miles,
but obviously it isnt. Any other ideas?
Adam
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ned
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| posted on 2/2/06 at 11:33 AM |
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ecu sensor fault somewhere would be my guess. vw's are common for air flow sensors going faulty, maybe something similar for a volvo?
a quick plug into the diagnostics would normally elimate/identify if this is the case.
Ned.
[Edited on 2/2/06 by ned]
beware, I've got yellow skin
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phelpsa
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| posted on 2/2/06 at 11:35 AM |
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YES NED!
That makes sense, faulty air flow senser = more fuel = drop in mpg and flooded engine! 
I'll check that!
Adam
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dave-69isit
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 posted on 2/2/06 at 11:40 AM |
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engine problem
when was it last serviced is the cold start electric i had this problem on my reno <my cable was chaved> same simtoms
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britishtrident
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| posted on 2/2/06 at 11:46 AM |
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If it has an airflow sensor that is the likely fault they get contaminated it is possible to clean them but it rarely puts the sensor back to as new
spec. With BMW diesels the normal diagnostic procedure is to disconnect the sensor and see if the problem improves.
If the vehicle EOBD diagnostic port I would advise using a scanner to retrieve the OBD codes.
Text below is taken from "Rover Rons" Rover 75 Diesel pages
-----------------------------------------------------------------------
a) MAF SENSOR FAILURE
This usually occurs after a journey in heavy rain and spray. It is caused by spray being drawn into the air intake, and eventually impinging upon the
Maf sensor. The poor quality Bosch heated sensor doesn't take kindly to taking a shower and expires before its time. A new one costs about £165,
but a Mafam MF75 will compensate for any signal degradation so only replace the maf if it is completely dead or as good as. ..
Symptoms: These vary depending how the maf is failing and may include some or all of the following:-
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Loss of performance below 2000rpm, possibly ok above 2000rpm.
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As above & / or marked reluctance to rev.
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Uneven running at low revs, smokey exhaust, & 'choked' feel when pulling away. (needs more more revs to pull away smoothly)
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Temporarily unplugging the maf cable gives an immediate improvement
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Cleaning it with isopropyl alcohol (details here) can give a temporary improvement.
----------------------------------------------------------
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graememk
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| posted on 2/2/06 at 12:05 PM |
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i was about to suggest air mass meter..
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Agriv8
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| posted on 2/2/06 at 12:20 PM |
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Agree air mass meter. On my 2nd on VW passat TDI with 200,000 on clock. A flat spot was the symptoms both times. still on original injectors
Would also follow neds thoughts on other sensors fault.
Unconfirmed but I belive German Swedish and french have started doing air mass meter rebuild kit for the bosch meter have a look at there website.
I would be surprised if it was the injectors ( ie 4 going all at once ) another option is a really dodgy batch of fuel that's clogging the
injectors - Worth a try running some redex injector cleaner through it.
Reagrds
Agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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britishtrident
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| posted on 2/2/06 at 04:22 PM |
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With the BMW unit it is possible to fit a a much cheaper Pierburgh sensor in place of the Bosch unit. The Pierburgh unit however lacks a built in
inlet air temperture sensor (IAT) so a seperate unit has to be fitted somewhere in the airflow that will give representative temperture readings.
see
http://45zs.info/Pierburgh/pierburgh.htm
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rusty nuts
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| posted on 2/2/06 at 08:23 PM |
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Euro Car Parts do VW mass air flow meters for around £50 , not sure with your car but some Volvos use a VW/ Audi engine. Worth a phone call
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phelpsa
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| posted on 2/2/06 at 08:50 PM |
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The D5 engine is the volvo 5 cyl one. Don't think the Maf will be the same.
Adam
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britishtrident
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| posted on 3/2/06 at 08:37 AM |
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Most of the modern MAFs seem to be the same or very similar certainly between BMW, Merc VW Diesels and even the older series of pre-BMW Rover
diesels.
Most fuel injection sensors sing from the same hymm sheet.
[Edited on 3/2/06 by britishtrident]
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