c70 p1171

[soberbro]

Hi there.

First of all I just want to say hi as this is my first post on that forum.

I have bought volvo c70 2001 and I have a car engine management light turned on. It turns out it is p1171 and it mentioned something about Fuel Adaptation Unit as far as I remember.

Now, MAF sensor is brand new and there doesn;t seem to be air leakage in the hose and around. I have no problems with rpm hesitation or any abnormal behaviour when it comes to engine. Although some times the car doesn;t start first time once in 15 engine starts-( when it won't start it usually takes like around 4-8 tries sometimes).

I am not sure if the fuel consumption is normal too.

Driving around London it says it does on average 16MPG
and on Motorway its never more that 25MPG

It is Volvo c70 2.5 turbo petrol.

I will appreciate any ideas. Thank you very much in advance.

[Luxobarge]

P1171 - long term fuel trim upper limit, I believe.

Why does it have a new MAF - did you put that on, if so why?

And more importantly what brand is it? If it's an aftermarket non-bosch MAF then I'd suspect that, as these cars are very picky about the MAF, and generally only the proper original-type Bosch unit with the correct Bosch part number will work properly.

Apart from that, favourite would be a leak in an intake pipe or vacuum line, it can take a while to check these thoroughly but worth it as they do perish and split over time.

[krussel]

Ref to MPG.

Sadly in city traffic these cars will suffer being pretty heavy. I am assuming you have an auto ? Mind you the manuals are not a lot better.

Mine has the 5 sp auto which seems to do a little better but town driving (not London) gives me 22-24 mpg. Tbh less than 20 in London is not surprising.

Once out on a B type open road things get a little better and 27-30 mpg is my ave on a short 7 mile journey to work.

Motorway driving is pretty fair in my 2.4 T and as long as you keep hovering around the legal limit 40 mpg can be achieved. Push a little harder on the outside lane and you can knock 5 mpg off that. However I ve never seen 25 mpg on the motor way unless you pulling 90 mph all the way ?

[Brianjone5]

I'd search this forum for threads about 'rich' running. Your mpg and difficulty starting occasionally point that way. There are a handful of possible causes. If the PO changed the Maf, it may have been a blind punt to fix this issue.

[byootox]

16 mpg is heavy even for one of these cars.
As Luxo asks and is really important is if the MAF is a decent one or just a cheapy ?
My T5 averages about 22-24 on a daily commute and can get into the low 30s on the motorway at about 60.
I know it's a right boring question but on the occasional starting issue.. when was it last serviced ? e.g good plugs, clean air filter etc
The p1171 code means the ecu thinks the engine is running lean and the fuel trim will show a high positive long term fuel trim to try and compensate.
It may well actually be lean or it may just think it is.
Well worth checking the breather and vacuum hoses along with the intake pipe between the maf and engine.
This code requires a little bit more diagnosis than some other ones as it doesn't actually point to any one item.
However a cheap Maf can cause more problems that it cures.
The big problem with mafs is they rarely fail completely, normally they go out of calibration which is a gradual thing and sometimes not even noticeable till your eml light comes on.