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General => The garage => Topic started by: dannyd126 on 11 January 2011, 12:14

Title: Ridiculous Fuel Usage
Post by: dannyd126 on 11 January 2011, 12:14

This is probably going to sound like a really amateur question to be asked by a mechanic but i just cant work it out.

But when my car runs on idle it uses a ridiculous amount of fuel, used twelve quids worth of fuel sat on idle for just under an hour while i was cleaning it. It aint head gasket or anything like that cause ive done all that recently. I first thought i might have a leak but ive checked the lines and the tank and its all fine.

It spits an unusual amount of water out of the exhaust when its sat on idle, i dont know if these are linked?

It does have a brand new cat on it which hasnt been ran in yet, which is probably screwed now due to the amount of water which has probably also flooded my 2nd lambda sensor, which is making it run really rich but didnt think it would be that bad.

FYI its a mk4 1.6 16v

Regards

Dan

Title: Re: Ridiculous Fuel Usage
Post by: AudiA8Quattro on 12 January 2011, 12:19

Try running VAG-com to see if you get any fault codes.
What are the emissions readings at idle? what was the last MOT like?

Title: Re: Ridiculous Fuel Usage
Post by: dannyd126 on 12 January 2011, 19:28

The last MOT it nearly failed on emissions cos the cat was screwed but its got a brand new sports cat on it so its hard to say.

It runs really rich even on idle

Title: Re: Ridiculous Fuel Usage
Post by: javalin on 14 January 2011, 15:11

coolant temperature sensor.

Title: Re: Ridiculous Fuel Usage
Post by: dannyd126 on 15 January 2011, 22:18

the temp sensor is brand new mate, replaced it like 2 months ago

Title: Re: Ridiculous Fuel Usage
Post by: rossbarry1 on 19 January 2011, 20:04

My 8v was doing this because of a dodgy connection on the air flow meter. Could be the same?

Title: Re: Ridiculous Fuel Usage
Post by: rubjonny on 20 January 2011, 10:00

gen vag sensor? if not that could be it as the pattern ones are rubbish.

as above check vag-com, not just for faults but look at the measuring blocks. this can show you what ecu sees from ecu and inlet temp sensors, plus throttle angle etc.

does it take ages to warm up, if sop stat could be buggered. common fault on them, replace the stat housing too as there is liek a peg on there which the stat needs to push on, which often snaps off.

if all the above is ok, try disconnectign the lambda probe. if car is much better then you need a new one

Title: Re: Ridiculous Fuel Usage
Post by: dannyd126 on 20 March 2011, 17:51

i think its cos of the map sensor, came up with a fault on obd-2 so im replacin it this weekend