Bad Fuel Economy, Poor Starting From Cold

[stealth_pug 0]

My gti seems to be getting really bad fuel economy at the moment, 20 quid sees about 100 miles, no matter how I drive it, like I stole it, like my grandad, motorway, A road, town, short journeys long journeys etc it always returns about the same. Which seems a little low to me?

 

During the winter It ued to be a bit lumpy when first starting, I'd fire it up and it would start first time but then I'd have to feather the throttle to keep it running for a couple of minutes until it had warmed up and it would be very kangarooy and juddery and generally just didn't like it, it also had a bit of a rich fuel smell to it, now its running a little better now the temps picking up but still not as well as it should be.

 

Anyone got any suggestions or know what I should be checking first? The fuels getting to me the most, at the moment I'm having to cycle everywhere to save money, not good!

[Anthony 1,003]

Remember £20 doesn't really get you very much these days - assuming you're paying around £1.20 a litre, that's 16.6 litres for £20, which works out at 27.4mpg. Not particularly good, but not terrible either especially being winter and if there's alot of short / town journeys.

 

Not only that, but trying to accurately measure fuel economy by seeing how far you get on £x isn't particularly accurate either, especially with the laughable accuracy of a typical 205 fuel gauge!

 

Causes of poor fuel economy and ways to improve it have been discussed countless times - a search will bring up pages of information.

[MerlinGTI 3]

ECU temp sender (£17ish) is what sprung to mind from reading your title might be worth cleaning out your SAD while your in that area too.

[Wes 86 1 Cars]

does anyone have a pic of where and what the ecu temp sender is? also what is the sad? im having the same symptoms and need to start sorting it out.

[Guest steveontwin40s]

Hi, the SAD is a unit under the dizzy that allows unmeasured air into the manifold by by-passing the AFM this highers your idle when the engine is cold to stop stalling, it switches off when the engine warms up. sorry dont have a pic of the temp sender, have you checked your AFM very common to playing up!

[Wes 86 1 Cars]

i haven't checked any thing yet as i was told it was probably a sticking valve but im not so sure now reading this. when i start the car from cold it revs straight up to 3k revs then drops to about 1500 after about a minute. seems way too high for a cold start.

[Grim.Badger 15]

Hi, the SAD is a unit under the dizzy that allows unmeasured air into the manifold by by-passing the AFM this highers your idle when the engine is cold to stop stalling, it switches off when the engine warms up. sorry dont have a pic of the temp sender, have you checked your AFM very common to playing up!

 

Actually it lets extra measured air in by bypassing the TB.

 

ECU temp sender is a blue headed bosch type sensor that is usually either on the heat exchanger part of the SAD (under the dizzy and a nest of wires) or around the back of the head next to the dizzy with two other sensors (also coolant temp, but this time for the dash).

 

Chances are that if you change the ECU temp sensor and give the SAD a good clean out, the car will be much better.

[porter_bmx 0]

a friend of mine is having the same problem, he's only getting 50 mile to £20 worth of petrol if that. he also has a high tickover when he starts it from cold, then drops when warm. you think this could be the same problem?? dont ask what the tickover is because his rev counter has the trade marks of a french car (don't work)

[Wes 86 1 Cars]

well i have ordered a new cts from partco today for 7 quid odd plus the vat, gotta be worth a try for that money. i'll let you know if it works.

[TU_Later 0]

Having EXACTLY the same problem, it wont idle till warmish.. then it'l idle lumpy around 1k, and its juddery to drive at light throttle.. Smells rich as hell when ticking over, but the 100miles to twenty quid.. I thought that was good for a 1.9! Mine seems a little less than that (When the fuel gauge knows what it's doing)

 

Ill clean out my SAD and think i'll look at a new temp sender too.. Then ill write back!