Poor MPG

Level 7 User Joined: 12 Mar 2005 Posts: 243

Right over the past few weeks I have been recently getting quite poor MPG compared to normal, struggling to get 30mpg where I used to get 35/36 on a regular trip and 45+ on a long one. Only real things I have to go on are fairly strong wiff of petrol when starting, high idle when cold and low when warm. Exhaust has recently started popping etc when I come off the throttle, its always done this to a degree but its doing it more now than it ever has. CTS or dodgy map sender/pipe spring to mind but is there anything else (lambda sensor?) that it could be.

Retroholic Joined: 23 Dec 2005 Posts: 3315

keep it under 4k Wink

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

CTS

Level 7 User Joined: 12 Mar 2005 Posts: 243

That was simple enough, one new CTS on its way.

Level 9 User Joined: 03 Jul 2006 Posts: 412

Mine isn't great on fuel economy either, never had it above about 37.5 mpg. It has a strong exhaust smell when starting too, but always idles fine at 950rpm. Worth me sticking in a new CTS at all?

Level 3 User Joined: 14 Aug 2006 Posts: 64

Try borrowing one for troubleshooting purposes

Level 9 User Joined: 03 Jul 2006 Posts: 412

Why, is a new one expensive? Anyone got one to borrow? Very Happy

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

only a tenner for a new one!

Level 9 User Joined: 03 Jul 2006 Posts: 412

Â£10 well spent if I get another 10mpg Laughing

Level 9 User Joined: 03 Jul 2006 Posts: 412

What's it called?

GSF: Temperature Sensor R93495 Â£9.50
Euro: 224745020 COOLANT TEMP SENSOR CLIO ESPACE TRAFIC R5 R19 R21 R25 GAUGE/WARNING LIGHT 2 PIN Â£13.64

Either of these? "temperature sensor" doesnt sound too specific Confused

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

first one

Level 3 User Joined: 14 Aug 2006 Posts: 64

Well, if one is available from a friend's car, you will have the chance to save some.

In fact, if a friend's car is available you could try also the lambda sensor.

Could also be worth cleaning the injection system.

Rolling Eyes

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

Or just unplug it.

Site Subscriber Joined: 23 Jan 2005 Posts: 502

Gentle Ben";p="105499 wrote:

Or just unplug it.

You mean the lambda sensor.

That should make it backfire.

Level 3 User Joined: 14 Aug 2006 Posts: 64

Yes.

When the lambda sensor goes, the ECU will recognize it and adopt a fixed value (I think 0,925 Volt) for its Lambda input. This can cause your symptons, but it could also be the CTS, like Chris says, and he's usually right

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

unplugging the lambda will not make it back fire.

if it was plugged in then for 10 cycles it will idle poorly then run ok.

Site Subscriber Joined: 23 Jan 2005 Posts: 502

When I first got the car it had the decat pipe on with the lambda hole in the exhaust plugged.
It used a lot of fuel and backfired like crazy on lift off.
Now got the decat pipe on and the lamdba. Ok it pops a little bit but not big time. (Well on max lift-off coming down the side of a mountain the other day it let one off like a hand grenade in a sewer pipe)
Maybe its the Fastchip Eprom.