milage mileage... the holy grail

hi there, still trying to improve my milage on my 1987 1050cc VW polo. from my odometer calculations i have been getting around 20mpg for the last 2 years.i can remember doing better than 35mpg for urban driving.observations so far:

-odometer: drove a bit behind a friends car.mine is 9% slower than his, but this translates to a incr of 2mpg only (i want 35mpg!!)

-spark plugs: mine (compared to the haynes color page on plugs) they are a nice tan brown, not black with carbon or oily.gapped ok

-air/oil filter: changed annually

-wheels: jacked car and spun each to see if they are binding.

-choke: rpm does actually go down from 1500 to 750 after 1 minute

-ign timing: spot on with strobe

-distr cap & rotor: changd last year,no improvement.

-carb: cleaned out float bowl and jets this year.

-tyres:kept inflated correctly with my own pump

-boot: only spare tyre & jack. no junk

i am at loss of what to try before taking it to a garage. i am contemplating polishing exterior and removing mirrors to gain a few mpg !

also: i pulled each lead off one at a time with the engine running and each cylinder appeared to be contributing well. i have never had the ignition leads changed. do new leads give better mileage or is it either it works or it doesnt part?

thanks for patiently reading my post

Reply to
beerismygas
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Blimey - I get over 33mpg out of my 2.0 Omega !

Perhaps try a little less wellie on the loud pedal?

Chuck

Reply to
Chuck Bodgers

Replace the engine breather canister at the rear of the engine, just above the sump, also replace the pipe that goes into the carb. (Very Important) - Make sure the pipe underneath the manifold is still there..... Replace the rubber insulating gasket underneath the carb and test the electrical fuel pre-heater underneath the intake manifold. (Very Important) Also check the compression ratios and make sure a valve is not leaking, this I have found to be fairly common on the polo's I have owned. Check the Valve clearances, You will need feeler gauges and a size 7 Allen Key. (See Haynes manual for specs) Check the timing and replace the points if yours is old enough to have them. If you have point seriously consider replacing them with electronic ignition, makes tonnes of difference. Check the clutch is not slipping at speed, find a steep hill and drive up it, foot to the floor in third gear, if the engine revs increase then it is slipping. Check the rear drums are not binding. Check the front disks are not warped. Check the wheel alignment and the condition of the track control arms. ( causes uneven tyre wear usually) Loose weight. Take your foot off the break whilst driving.

Andy

Reply to
Nik&Andy

Good giddly god. I got better than that from my mum's 1043cc Polo and you've never seen a car so mercilessly thrashed in your life. Every accelleration was a flat out hammering, every corner was left foot braked and drifted round, half the gearchanges didn't involve the clutch...

Reply to
doki

SHIT, Forgot to state the most common faults of all.......

Check the Engine reaches operating temperature (Thermostat)

And the most common cause of bad MPG in a polo is the rubber diaphragm fuel pump leaking petrol into the sump, you won't see this leak until you remove and test the fuel pump.

Andy

Reply to
Nik&Andy

Have you got a locking petrol cap? Seriously, could someone be siphoning your tank on a regular basis?

Also, in addition to the other advice, are you sure your tyre pressure gauge is okay? It's possible that your under-inflating all your tyres because of a faulty gauge.

Tim

Reply to
Tim Downie

How does one test a mechanical fuel pump?

do you unbolt it and blow through each end? what should i expect to find/look for?

thanks

Reply to
beerismygas

siphoning

yes its lockable.i did consider a petrol station might be giving less fuel, but i fill up at many different stations and every now and then fill up a jerry can too.

the tyres are inflated pretty stiff,they hurt when kicked,but i will double check this against a second gauge tomorrow.

Reply to
beerismygas

if you only do very short or very strenuous journeys then it might get as low as you say, but late 30s should be obtained with reasonable driving in good conditions. do you fill completely, reset the odometer, drive for a couple of hundred miles, fill again and work out the consumption? you should get 7 plus miles per litre, to convert to mpg multiply by 4.54

mrcheerful

Reply to
mrcheerful

Take it off, check for evidence of fuel running down the drive shaft, I don't really know, maybe one of the other chaps can help. My fuel pumps have always failed with obvious results (NO FUEL WHATSOEVER)...

But it is known that mechanical diaphragm pump can weep fuel down the driveshaft into the engine.

You could also check the oil and see if it looks very diluted I guess and see if the oil level has risen slightly maybe!.

Andy

Reply to
Nik&Andy

short and strenuous? I drive a 2litre turbo like i stole it and still get

25mpg (measured mixed urban and motorway over 1000 miles) ... he must have something wrong, it has to be more than just his driving style.

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Reply to
Mad Ad

On 25-Apr-05 18:04:22, beerismygas said

I'm only a white belt at this, but does the engine reach the correct working temperature?

All the best, Angus Manwaring. (for e-mail remove ANTISPEM)

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Reply to
Angus Manwaring

yes i just checked that today, kept an eye on the temp gauge while driving.

measured the resistance of the HT leads too. they all gave more or less the same reading of K ohms

Reply to
beerismygas

Now I know you are crossposting and I have read your other posts I think we may have the answer - Your car being an '87' has points, not electronic ignition, yes?

If so, check and change the points, but more importantly check the vacum advance system is working properly as this will adjust the ignition timing whilst you are on the move.

Also have you checked the valve clearances yet?

This has to be a problem with either timing or the carb.

Andy (Nik&Andy)

Reply to
akd

will do.thanks

Reply to
beerismygas

Try unlearning your bad driving habits. Stop driving so close to the bloke in front. Try and time it so you don't need to stop at traffic lights/roundabouts. Coast up to a stop in gear with foot off accelerator (more beneficial on fuel injection).

The smoother you can drive and the less you need to stop, the less fuel you'll use.

Reply to
Conor

drove like a complete idiot though, I still don't think he could get mpg that low. Due to the fact that he's concerned about his fuel consumption I suspect that he doesn't drive like a complete idiot, so a different driving style will probably decrease the consumption by less than 10mpg. I would expect at least double the mpg he's getting! Of course, what you've suggest is good advice, and always helps.

Reply to
petermcmillan_uk

Fuel leak from a corroded fuel tank, or even simply a bit of perished fuel line?

Is the crankcase breather/cam cover breather bunged-up or perished?

Reply to
R. Murphy

since fuel is so evaporative how will you tell if you have a leak unless its a gusher?

Reply to
beerismygas

You probably won't - but if you have less-than-perfect ends (so to speak), trim them off and try it and see.

Reply to
R. Murphy

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