More mpg issues with the 1.4 16v
- Thread starter Jgbaudia2
- Start date
scimmyowner
Member
Hi - could be the pre cat lambda sensor - is the yellow engine management light illuminated
Dave
Dave
Also changed that a few months back as it was showing a management light so now all good with it
Kleynie
A2OC Donor
Ouch! Ours does 10mpg more than that around town
Vorsprung durch Technik
A2OC Donor
Wow 25 mpg is low. I take it the thermostat is good? Does the temperature on the gauge reach 90 degrees?
Yea gets to 90 ok now I’ve also replaced the thermostat too
Jags C20LET
Member
I fill up with 3 gallons at a time and that lasts 100 miles around town, and she returns 50mpg on a nice 70mph M1 cruise
I’ve only got a basic diagnosis so not sure how you check (vcds)
Appeal for a local member to give you a free VCDS scan, failing that a garage but they would more than likely charge and it might not reveal anything. Its just it would be interesting to see a VCDS scan.
Andy
jonbad
Member
Found this thread as concerned I'm suffering a similar problem with my 1.4 BBY engined A2.
I've literally not done anything just yet to look at it as am in all manner of different cars all the time due to my job. Anyway, my suspicion is the throttle body and the car effectively running on choke the whole time. This would explain why it runs absolutely fine but the mpg is dire at present and far worse than it used to be. Have had the car more than five years and done many thousands of miles, so I know something's up. But, no light on, temp looks okay and temp sensor should be fine. Lambda sensor might be at fault, as did previously have the light on, but it isn't at the mo and hasn't been for a while. Gave it a throttle body clean (second in my time with the car) last year and, I think, that's when the issues might have started. I reset the throttle body as you're supposed to using vagcom so perhaps it's not set right. Not sure if any of this will help your case, but as a rough guide I used to get a consistent 350-400 miles from a tank depending on long runs or town driving. 250 is dire and about what I'm getting at present too. Hope this helps!
I've literally not done anything just yet to look at it as am in all manner of different cars all the time due to my job. Anyway, my suspicion is the throttle body and the car effectively running on choke the whole time. This would explain why it runs absolutely fine but the mpg is dire at present and far worse than it used to be. Have had the car more than five years and done many thousands of miles, so I know something's up. But, no light on, temp looks okay and temp sensor should be fine. Lambda sensor might be at fault, as did previously have the light on, but it isn't at the mo and hasn't been for a while. Gave it a throttle body clean (second in my time with the car) last year and, I think, that's when the issues might have started. I reset the throttle body as you're supposed to using vagcom so perhaps it's not set right. Not sure if any of this will help your case, but as a rough guide I used to get a consistent 350-400 miles from a tank depending on long runs or town driving. 250 is dire and about what I'm getting at present too. Hope this helps!
depronman
A2OC Donor
the most likely cause is the engine temp sensor
it as two circuits one which feeds the gauge on the dash and another which feeds the ECU, my bet is the ECU is seeing a constantly low temp and hence fueling for this low temp even when the engine is fully warmed up.
VAGCOM can be used to monitor the temp feeds from both circuits which should be within a few degrees of each other
The temp sensor is prone to failure, but is cheap, under £10 so worth changing to see if it makes any difference
If otherwise the engine starts and runs fine I'm 90% sure this will be the problem
cheers,
it as two circuits one which feeds the gauge on the dash and another which feeds the ECU, my bet is the ECU is seeing a constantly low temp and hence fueling for this low temp even when the engine is fully warmed up.
VAGCOM can be used to monitor the temp feeds from both circuits which should be within a few degrees of each other
The temp sensor is prone to failure, but is cheap, under £10 so worth changing to see if it makes any difference
If otherwise the engine starts and runs fine I'm 90% sure this will be the problem
cheers,
jonbad
Member
If you're referring to my point about the throttle body, then that can be reset, which is something to do after a throttle body clean specifically. Resetting in other ways as mentioned isn't really possible as such.
In my case, I've changed one of the temp sensors before and it is an easy and relatively quickly fix and so I may try this again, although what I'm experiencing now isn't similar to what I had before.
As for your case, I think you really need to see what the temperatures are of the engine using vagcom and see if that's the problem as has been indicated.