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Very poor mpg all of a sudden
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- Newbie
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- Joined: Thu Aug 18, 2016 11:33 pm
Very poor mpg all of a sudden
Hope someone can help here, have an e85 and about a month ago when I filled up a full tank rather than the computer saying I could do about 400 miles as it normally does it said 260, I checked the mpg and it read 30 which was fine, next time I filled up the same thing occurred, I reset the mpg calculation and its now calculated I get about 22 which is horrendous. Inflated tires so no issues there. Today was driving an when pulling off in first car felt like it wanted to stall due to shaking. Does anyone have any ideas as to what might be going on here?
Thanks so much.
Thanks so much.
BMW Z4 E85, 06, 2.5 SI
- ph001
- Lifer
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- Joined: Mon Oct 31, 2016 5:53 pm
- Location: N. Yorkshire.
Very poor mpg all of a sudden
What engine?
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- Newbie
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Very poor mpg all of a sudden
BMW Z4 E85, 06, 2.5 SI
- ph001
- Lifer
- Posts: 3870
- Joined: Mon Oct 31, 2016 5:53 pm
- Location: N. Yorkshire.
Very poor mpg all of a sudden
Hmmm that's the N52 engine so problems like this are quite rare. Could be a lamba sensor which is screwing the mixture up. Does it drive OK otherwise? No engine warning lights? Idles OK? Power OK?
Next stage really is to get a code reader on it to see if it has any codes stored and look at live o2 sensor readings. Where are you based?
Next stage really is to get a code reader on it to see if it has any codes stored and look at live o2 sensor readings. Where are you based?
- Silverzedtom
- Senior Member
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- Location: East Sussex
Very poor mpg all of a sudden
As above, it needs plugging in to a good scanner.
Certainly sounds like a sensor though.
Are all of your brakes good? As in wheels spin freely? Doubt it’s going to be this but maybe worth a shot.
Certainly sounds like a sensor though.
Are all of your brakes good? As in wheels spin freely? Doubt it’s going to be this but maybe worth a shot.
E85 2.5si
F55 Cooper S
F55 Cooper S
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Very poor mpg all of a sudden
ph001 wrote: ↑Tue Oct 09, 2018 12:38 pm Hmmm that's the N52 engine so problems like this are quite rare. Could be a lamba sensor which is screwing the mixture up. Does it drive OK otherwise? No engine warning lights? Idles OK? Power OK?
Next stage really is to get a code reader on it to see if it has any codes stored and look at live o2 sensor readings. Where are you based?
Hello, I'm going to buy a Bluetooth adapter so I can check o2 sensor data as I guess that's the most likely culprit. It drives fine other than the fact it was shaking when taking off in first gear today, the tires etc. are fine, no warning lights appear so my basic obd2 reader can't pull anything.Silverzedtom wrote: ↑Tue Oct 09, 2018 12:43 pm As above, it needs plugging in to a good scanner.
Certainly sounds like a sensor though.
Are all of your brakes good? As in wheels spin freely? Doubt it’s going to be this but maybe worth a shot.
Is it more likely to be o2 sensor than sparkplugs or MAF?
Based in cambridge.
BMW Z4 E85, 06, 2.5 SI
- ph001
- Lifer
- Posts: 3870
- Joined: Mon Oct 31, 2016 5:53 pm
- Location: N. Yorkshire.
Very poor mpg all of a sudden
It's common for the upstream sensors not to cause codes when they go dodgy. My guess is that one or both of them are only swinging from about 0.1 to 0.4V instead of the 0.9V they are supposed to do. Probably also 'laggy' in their response.
MAF is a possibility but defo not a common fault on these cars. It would be last on my list. Won't be plugs with those symptoms.
MAF is a possibility but defo not a common fault on these cars. It would be last on my list. Won't be plugs with those symptoms.
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Very poor mpg all of a sudden
Thanks, I won't be able to understand what the results from the scan tool mean so ill post them here when I get the tool and hopefully it will be clear if its the o2 sensor or not and I can go from there.ph001 wrote: ↑Tue Oct 09, 2018 1:00 pm It's common for the upstream sensors not to cause codes when they go dodgy. My guess is that one or both of them are only swinging from about 0.1 to 0.4V instead of the 0.9V they are supposed to do. Probably also 'laggy' in their response.
MAF is a possibility but defo not a common fault on these cars. It would be last on my list. Won't be plugs with those symptoms.
Thank you.
BMW Z4 E85, 06, 2.5 SI
- ph001
- Lifer
- Posts: 3870
- Joined: Mon Oct 31, 2016 5:53 pm
- Location: N. Yorkshire.
Very poor mpg all of a sudden
Yeh, you need to get the car fully up to temp then post a video of the values on Youtube and link to it. First do idle then rev to 2,000rpm and hold it steady for 30 secs or so.
- Crazy Harry
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Very poor mpg all of a sudden
OK so I'm going to ask the low tech question - have you covered as many miles between fill ups as you would have normally done? the gauges say you are using more fuel but are you - its then gauges or poor consumption.
If its poor consumption - does it need more revs to get it moving / will it free wheel? this should point you to binding brakes or engine problem
Engine - get a reader and follow the advise above
If its poor consumption - does it need more revs to get it moving / will it free wheel? this should point you to binding brakes or engine problem
Engine - get a reader and follow the advise above
- Jembo
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Very poor mpg all of a sudden
You sure your other half hasn’t been out hooning while ur not looking?
Joined the dark side with a ///M Hell Bronze Sepang Coupe
Ex Aug 2005 Maldives Blue 3 litre cruizer, lots of toyz,
Lifer 54
Ex Aug 2005 Maldives Blue 3 litre cruizer, lots of toyz,
Lifer 54
- Mr Tidy
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- Location: North West Surrey
Very poor mpg all of a sudden
That made me smile!
Back in 2010 I was working abroad for about 6 weeks and Mrs Tidy used my car a few times just so it didn't sit idle - average MPG dropped dramatically!
Coupes because stunning!
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
- Jembo
- Lifer
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- Joined: Sat Jun 25, 2011 11:59 pm
- Location: 1066 Country
Very poor mpg all of a sudden
My Mrs Jembo exceeds manufacturers claimed MPG... I’m at a total loss how she does it but Hell will have to freeze over before she gets anywhere near the Zed’s keys
Joined the dark side with a ///M Hell Bronze Sepang Coupe
Ex Aug 2005 Maldives Blue 3 litre cruizer, lots of toyz,
Lifer 54
Ex Aug 2005 Maldives Blue 3 litre cruizer, lots of toyz,
Lifer 54
- Mr Tidy
- Legend
- Posts: 23789
- Joined: Wed Jul 02, 2014 12:18 pm
- Location: North West Surrey
Very poor mpg all of a sudden
Mrs Tidy will never get the Z keys either - we now live at different addresses!
Coupes because stunning!
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
- skelters
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- Location: Greenock, Scotland
Very poor mpg all of a sudden
I'm just surprised some of you have an other half!
What fuel are you putting in the car? Unleaded, BP Ultimate, Shell V-Power, Tesco 99?
What fuel are you putting in the car? Unleaded, BP Ultimate, Shell V-Power, Tesco 99?
2007 Z4 3.0si Sport. Silver Grey Metallic, Brembo Brakes, HEL Braided Brake Hoses, Machine Monkey Exhaust Tips, Stubby, Piano Black trim, Black Leather, Bilstein B12-Pro-Kit, Michelin Pilot Sport 4 on MV2's. Roof Motor in the Boot!