mk 4 vw golf 1.6 sr poor fuel economy. HELP!!!!

[mikeymagic]

Hi all, im a new member to pistonheads and need help!!!

i have bought a mk 4 golf 1.6 sr its a 99 model and seems to be useing way to much fuel.
it has only done 85k with a full service history but not a vw one it has been done by a vw specilised
it has had one lady owner since new.
i filled it up with £60 on friday 11 march and done 200 mile and have got just over a quarter left in the tank.
it also smells as if it is running rich,
also when you rev it when stationary the revs drop right down and sound as if it wants to stall and the lights dim at the same time
it will do it a couple of times the settle.
sorry for the long message and thanks for taking the time to read.

michael.

[Jimmyarm]

Could be loads of different things, take it to a garage and get them to look at it

Also consider http://pistonheads.co.uk/gassing/topic.asp?h=0&amp...

[mikeymagic]

hi, just got it into vw for a health check (its free) so hopefully they will find something.

[blaineuk]

o2 sensor in the exhaust could be faulty.

[va1o]

MPG on them is generally rubbish

See http://uk-mkivs.net/forums/t/383674.aspx?PageIndex...

[Jw Vw]

va1o said:

MPG on them is generally rubbish

See http://uk-mkivs.net/forums/t/383674.aspx?PageIndex...

This is true I normally get about 320-340 miles out of a tank in my 1.4 MK4! There was a recall for 1.6s regarding poor fuel economy was something to do with the ECU. Have a look on UK-MKIVS forum and it should shed some light on you're issue.

[kmc1]

mikeymagic said:

hi, just got it into vw for a health check (its free) so hopefully they will find something.

Rest assured they will definately find something.

[Willy Nilly]

mikeymagic said:

hi, just got it into vw for a health check (its free) so hopefully they will find something.

It won;t end up being free. You'll need new pisstake valves and dangle berry adapters for a start.

Have you put any fuel in it to find out what it has used? Don't believe the fuel gauge

[maniac0796]

Is it getting up to temperature? Or does it have a faulty temp switch?

Make sure you get the cat checked if you think it smells rich.

[Chicane-UK]

It's more than likely going to be a sensor or something which has gone duff. Be it an airflow sensor, coolant temp sensor or something like a lambda probe. You're going to need to get it to a dealer or specialist...

[Rich_W]

NB: Free Health checks at VW don't always include diagnosis of a fault. It's just basic visual things. Pads, tyres, oil level. You'll need to budget for looking into the fuel thing.

[seany87]

I had the exact same car with the same issues. Change the MAF sensor and clean out the throttle body with carb cleaner.. if that doesnt work I will eat my hat.

I never got mine over low 30's mpg around town. It loved super unleaded from shell, felt a lot more responsive and got a couple more mpg

[mikeymagic]

maniac0796 said:

Is it getting up to temperature? Or does it have a faulty temp switch?

Make sure you get the cat checked if you think it smells rich.

hi temp is fine sits at 90 when gets warm.
as for the cat the system does sound like its blowing.

[mikeymagic]

seany87 said:

I had the exact same car with the same issues. Change the MAF sensor and clean out the throttle body with carb cleaner.. if that doesnt work I will eat my hat.

I never got mine over low 30's mpg around town. It loved super unleaded from shell, felt a lot more responsive and got a couple more mpg

hi, i have been told about this but im not very mechanic le minded,
is it the bit that is just off the air box with the wire coming out????
how would i clean out the throttle body?

cheers

[rallycross]

£60 of petrol at £6.50 per gallon, 200 miles covered, you are lucky you still have some left in the tank.

those old mk4's suffer from problems with stepper motors in the throttle body and airflow meters that would make it run rich with uneven idle - not cheap to fix. Get local garage to clean out throttle body and put some carb spray on it - see if its any better.

[seany87]

mikeymagic said:

hi, i have been told about this but im not very mechanic le minded,
is it the bit that is just off the air box with the wire coming out????
how would i clean out the throttle body?

cheers

Yeah, its the metal part where the wire leads to. the wire is your throttle cable the metal bit is the throttle body. Dismantle the airbox / unplug air flow sensor so you can gain access to the throttle body, making sure not to damage anything. get some carb cleaner once you have taken off the throttle body, spray a bit of the cleaner on a microfibre cloth and rub. Marvel at the shiny metal underneath the caked on crud. Mine was thick, sooty crap covering EVERYWHERE. Make sure the throttle body is bone dry and clean of any fibres when you reassemble. It should run much better. Think it needs doing every 50k miles as a guide, they get clogged easily on these cars.

[mikeymagic]

seany87 said:

Yeah, its the metal part where the wire leads to. the wire is your throttle cable the metal bit is the throttle body. Dismantle the airbox / unplug air flow sensor so you can gain access to the throttle body, making sure not to damage anything. get some carb cleaner once you have taken off the throttle body, spray a bit of the cleaner on a microfibre cloth and rub. Marvel at the shiny metal underneath the caked on crud. Mine was thick, sooty crap covering EVERYWHERE. Make sure the throttle body is bone dry and clean of any fibres when you reassemble. It should run much better. Think it needs doing every 50k miles as a guide, they get clogged easily on these cars.

hi, ive took the air flow sensor off and gave it a clean, put it back on and that has stopped the revs from dipping when you rev it so it ticks over fine now. im going to get some carb cleaner tomorrow to do the throttle body. it also seems to have stopped the rich smell but ill keep you posted on that.

thanks to you all for your help its much appreciated

[3sixty]

As everyone has said above, they are thirsty things.

I had mine for 2 years, and was running about 25-30mpg average. Changed lambda probe, MAF, throttle body, temp sender... nothing helped. I chucked it in the end and got a MK5.

[dave9]

you still have a quarter tank of fuel in it.

doesn't sound too bad especially if local journeys.

if say it's £65 to fill up that's about ten gallons ish isn't it? if you have used 3/4 of this you have used between 7 and 8 gallons.

if you have used say 8 gallons then that's about 25mpg which isn't too bad in cold weather in stop start traffic and if you've used 7 gallons that's nearl 30mpg

[The fatboy]

200 miles for my 01 civic 1.6 would take about 2/3 of my tank i think, i could do about 320-360 for a full tank (50L)