VW Golf Mk4 1.6 - low mpg.. help!
VW Golf Mk4 1.6 - low mpg.. help!
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Discussion

3sixty

Original Poster:

2,963 posts

229 months

Tuesday 25th November 2008
quotequote all
I've got a 1.6SR Mk4 Golf for my sins... it was cheap and I needed a car as I sold my old one to buy a house.

Currently, filling it up with £35, so ~35 litres gets me around 120miles. Obviously this isnt good.

I've had it VAG COM'ed with nothing much coming up. I've replaced temp sender, MAF, lambda probe, air filter, fuel filter and pollen filter. I'm running out of ideas and is annoying me.

tried posting on uk-mkivs but nobody seems to have an answer.


Can anyone here help?



  • Edited to add: I understand the 1.6 is thirsty and its a heavy car... but seems stupidly low miles for the money. I'm not going to 9 million revs on gear changes, its driven sensibly. Its also done 120k miles, which is a lot and is a T reg, but again... surely must produce better figures than that?
Edited by 3sixty on Tuesday 25th November 11:44

Robatr0n

12,362 posts

246 months

Tuesday 25th November 2008
quotequote all
Try changing the plugs and leads.

Hereward

5,139 posts

260 months

Tuesday 25th November 2008
quotequote all
My 80k mile T-reg 1.6 SE manual returns 35-40mpg on a cruise (according to computer).

Good luck, let us know if you sort it.

3sixty

Original Poster:

2,963 posts

229 months

Friday 28th November 2008
quotequote all
I'm thinking maybe there is a shortage of air.. but how do I test pipes for leaks?

Tame Technician

2,467 posts

234 months

Friday 28th November 2008
quotequote all
Are the brakes seized on? the poor millage your are getting is so bad there must be a major problem, or your driving it around town, speeding up and slowing down a lot.

Get someone to reset/basic setting the throttle body, with 5051 or a vagcom, this can make quite a difference.

Is the air filter blocked?/ fitted correctly.

Any air leaks would make it run lean and loose power / throttle response, but wouldn't really change fuel economy, or it would be a bit better. squirt brake cleaner on the inlet manifold + breather pipes to check for leaks, if the brake cleaner gets sucked in the engine will stumble.

Wouldn't bother with plugs and leads unless you have a misfire.

How mush oil does the engine use, it could just be worn out and inefficient as a result. Thats a lot of miles, but i know some one with 205k on a 1.6, it uses a pint of oil every 1000miles or so but it still does 35mpg.

SamPet

485 posts

226 months

Friday 28th November 2008
quotequote all
New MAF please!

The Mass Air Flow meter could well be the culprit. It's a relatively expensive part as it contains a platinum filament. Worth doing an exchange at GSF (German Swedish French- it's a car parts place).

Otherwise, check your tyres, coolant reservoir sensor and coolant temperature sender (all cheap parts) as they can cause the car to run on "choke", which uses more fuel

Good luck

3sixty

Original Poster:

2,963 posts

229 months

Friday 28th November 2008
quotequote all
Tame Technician said:
Are the brakes seized on? the poor millage your are getting is so bad there must be a major problem, or your driving it around town, speeding up and slowing down a lot.

Get someone to reset/basic setting the throttle body, with 5051 or a vagcom, this can make quite a difference.

Is the air filter blocked?/ fitted correctly.

Any air leaks would make it run lean and loose power / throttle response, but wouldn't really change fuel economy, or it would be a bit better. squirt brake cleaner on the inlet manifold + breather pipes to check for leaks, if the brake cleaner gets sucked in the engine will stumble.

Wouldn't bother with plugs and leads unless you have a misfire.

How mush oil does the engine use, it could just be worn out and inefficient as a result. Thats a lot of miles, but i know some one with 205k on a 1.6, it uses a pint of oil every 1000miles or so but it still does 35mpg.
It has been suggested that my O/S rear brake caliper is sticking. I am looking to replace the brakes soon, but would this really cause such a huge drop?

Air filter has been replaced sicne the problem, and presumed to have been fitted correctly by a mechanic, but will check this tonight.

I've also been told my car does have a misfire. So may well change plugs and leads when I do a service.

Oil isnt really an issue, doesnt seem to drink that much to be fair. Petrol seems to be its main drink of choice.

3sixty

Original Poster:

2,963 posts

229 months

Friday 28th November 2008
quotequote all
SamPet said:
New MAF please!

The Mass Air Flow meter could well be the culprit. It's a relatively expensive part as it contains a platinum filament. Worth doing an exchange at GSF (German Swedish French- it's a car parts place).

Otherwise, check your tyres, coolant reservoir sensor and coolant temperature sender (all cheap parts) as they can cause the car to run on "choke", which uses more fuel

Good luck
See my first post! furiouswink

I've replace MAF and temp sender already. Got a new coolant bottle to go on, but this is more to resolve a coolant warning being incorrect as sensor is gone I think. Tyres are brand new (well, few months) and pressures are correct

Tame Technician

2,467 posts

234 months

Friday 28th November 2008
quotequote all
Its got a misfire you say. Well thats the first thing to fix, it will destroy the cat if you dont. That would cause loss of power and poor fuel ecconomy. Would have thought you would notice rather than being told it has one???

3sixty

Original Poster:

2,963 posts

229 months

Friday 28th November 2008
quotequote all
Haha, I'm not entirely mechanically minded. I've only been driving a few years, most of that with a diesel, so I've been accustomed to ignore engine notes unless they are of the exotic variety... so wouldnt have a clue what to do with it. I presume changing plugs and leads will help?

Edited by 3sixty on Friday 28th November 15:58