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cavedweller

old git needs Polo advice

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cavedweller

The last car I had was a 1988 Polo about 20 years ago and I've had nothing but old motorcycles since. However, I've just bought a 2000 Polo Hatchback 5-door with the 999cc engine in the most basic trim with nothing optional included, which suits me just fine. Roll-em-up windows and basic simplicity.

 

I bought it from a dodgy bloke in a pub car park in the dark for peanuts and he said it was owned by a little old lady who only ever used it to drive to church on Sundays. It has no body rot (VW galvanized that year) and it has almost a year's MOT left.

 

So it's basically a 20 year old car with a few minor niggles that people who don't work on cars would find daunting or expensive to fix, but I've been working on vehicles since before you were born so I don't mind a little upkeep but I've never owned anything as new as this and have no experience with things like fuel injection, ECU foibles or what the MOT man looks for these days so I need a little advice on a couple of things.

 

When I first got it the idle was erratic to say the least so when I got it home I popped the bonnet and took off the air breather and found ancient leaky air hoses and random electric shite which I started removing and throwing away. I've done stuff like this to vehicles for 40 years and they are always better for it. A petrol engine isn't rocket science and all that so-called pollution control complication is rubbish, and breathing crankcase fumes and who knows what back into an engine is stupid and unhealthy for the engine.

 

That idiotic massive air breather that probably weighed more than the driver's seat had to go in the bin and a small motorcycle pod filter the size of a coffee mug went on. I plugged off the two air lines to the throttle body and rerouted the crankcase and valve cover vent hoses so nothing goes into the intake anymore. After scrutinizing the fuel lines and figuring out what they probably did as regards the injection system I disconnected the electric tank breather valve and threw it away and removed the plastic cannister thing down by the radiator and now the vent hose from the tank is just open to the air so the tank can breathe. Then I dumped a gallon of diesel in with the petrol to clean the injectors. Worked a treat.

 

All that made the car run sweeter than I'm sure it has in ten years. Idles perfectly and goes strong for what it is, which is a 20 year old 50hp petrol engine so you can't expect anything wild but it trundles along brilliantly now. Absolutely no problems there.

 

I hate the fly-by-wire throttle pedal and see no reason why it was even used on so simple a car but I know it has to stay for now for the ECU and the fuel injection to work, at least until I can source a cable throttle body and a different ECU to match or a carb and intake, but for now it will stay as standard because it works.

 

However, what I'd like to know is how much crap can I get rid of before the ECU starts to complain or something? For instance there's a temperature sensor located down by the distributer that I've read often has issues either with bad wires or erroneous readings and that somehow causes the ECU to misbehave, so can I just get rid of it altogether? I won't use a thermostat in the engine so the water will always circulate freely anyway, so what's the temperature sensor even for and why does the ECU need it? I'd like to just get rid of it and be done with any future problems.

 

Then there's the idiot sensor bolted into the exhaust manifold. Stupid crap, needs to go, is there any way to dispense with it and still have a happy ECU and still get through the MOT?

 

And the strangling old catalytic converter is coming off as well as soon as I can find a fake straight through to fit because I know the MOT says this car MUST look like it has the pointless thing fitted.

 

I have read things about the immobilizer going bad as well. Where is it, and can I just get rid of it?

 

The simple primitive stuff I can fix, like the brakes and the suspension that need a bit of sorting before the next MOT, but primitive as this thing is it's still got an annoying amount of senseless computery crapola and I'd like to do away with as much of it as I can. Otherwise, it's a great car!

 

Edited by cavedweller

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nige8021

First Welcome to the forum.

 

All that emmission stuff (carbon cannister and valve)is best in the junk bin. The erratic idle could be down to a dirty throttle body (common problem) use an old toothbrush and some spray carb cleaner, under no circumstance try to open the butterfly by hand or you will then need a replacement unit !! to clean below the butterfly, remove it from the inlet manifold, but don't disconnect the electrical connector from it or you will need diagnostic kit to reset the learned values of the position sensors (and that goes for the cable operated throttle body as well, so TBH you might as well keep the fly by wire unit)  The temp sensor on the thermostat housing is a dual element unit with one section for the gauge readout the other is for the ECU and you will need that to ensure the thing starts correctly as it's data is used by the ECU to workout the injector timing shedules for cold/hot starts and for optimum fueling during normal running.  the sensors on the exhaust again are needed for the engine to run correctly and to pass the MOT emmisions test  

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dvderlm

Yeah, modern electronic bollox.

 

London introduced the ULEZ zone yesterday and I suspect most manufacturers have played their tricks for the emission test regime so even a NCAP 6

rated vehicle is actually bad in real-life (eg Nissan Qashqai). But we are only now learning that reducing CO2 is not enough and fine particulates and NO2 are a people and potentially planet killer.

 

My solution:

Dig a reservoir for rain water, plant a forest next to it of about 5 square miles, wait 15 years, rip all those sensors and heavy lumps of moving metal out of the car and fit li-ion batteries and an electric drive train.

Build a static wood-burning steam engine with a carbon capture chimney. Let it run day and night to drive a generator to recharge battery packs for the car and the chainsaws and irrigation pumps. 

Start collecting zinc from scrapped cars... 🙂

 

Thing is -as nige says - the sensor and feedback loop control the spark and fuel and air and resulting  by-products of hydrocarbon combustion to produce a responsive

and usually economical engine in a variety of weathers and usages - even as fuel mixtures are changed by season or over time to have more alcohol - with "reasonable" levels of Carbon Monoxide,

Carbon dioxide and Nitrogen oxides, but at presumed levels that will likely become more and more prohibitive for large cities.

 

I think the immobiliser is inside the ECU and transponder in key and needs dealer who trusts you and takes money to program new paired key.

Aftermarket ECU?

 

 

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nige8021

The immobiliser is a small box under the dash not much bigger than a ciggy packet, you can get the immobiliser requirement written out of the ECU for around £80 but again in general they don't play up that often

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vwfan3
On 09/04/2019 at 21:21, nige8021 said:

.........under no circumstance try to open the butterfly by hand or you will then need a replacement unit !! 

Please throw some light on this. I have just done this using a taped flat screw driver.

What will go wrong. Thanks in advance.

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cavedweller

Oops- I did that too when I was cleaning it up. Never having had a fly by wire throttle body on anything before I had no idea how they worked. I assumed there was some kind of servo or electric motor gubbins to open the butterfly. I cautiously poked at mine and and saw there was some resistance, but I went ahead and carefully propped it open with a big screwdriver to spray a bunch of carb cleaner in. I figured a slow prod with a screwdriver probably wouldn't hurt anything if it was electrically operated. Doesn't seem to have harmed mine but of course I know nothing about throttle bodies and wouldn't be surprised to discover it gives the ECU fits if you mess with it.

 

Having said that, from what I can see of the fuel injection and stuff on a 2000 Polo with a dinky engine it doesn't look TOO overly complicated so probably doesn't have a vastly complicated ECU either compared to a newer car. I'm still just learning how to deal with it. I know I should now get a diagnostic meter thing for resetting warning lights and stuff when I need to and for general upkeep but there's so many on the market at such a range of prices I'll have to do a bit more research to figure out which one I can get away with at the lowest cost. It's not like I'm going to be doing any major modifications to a 999cc engine.

 

It has already had a new timing belt and at the moment it runs absolutely sweet now that I've thrown away a lot of the air gasper crap under the bonnet and it actually seems to be getting the claimed 50mpg or so, which is fine by me for what it is. Cheap and cheerful to run and fix. Before next MOT I need to sort a couple of minor niggles but I was amazed at how cheap parts are for this car. Most of the the parts new seem to be even cheaper than parts for my bikes! I just bought a new starter for £55 brand new.

 

Anybody got any info on what's an adequate diagnostic thingy for cheap?

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caretakerplus

Its funny how little old ladies who only use their car once a week, always sell 'em on to dodgy blokes in pubs.

 

You must have been working on vehicles for a long time old lad, we are not all 17 year olds on here you know.

 

The old saying, "If you can't beat 'em, join 'em" comes to mind and I reckon that once you get used to all this modern 'crap', you will adapt to it and eventually wonder however you managed without it - My first car was an Austin Ten and I can tell you now that I wouldn't want to go back to it  -  (I have to admit that I wish I still had it though!)

 

Whatever problems you have with this car, you are never going to have a broken throttle cable 😐

 

Hope that things go well.

 

Regards.

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Yeti

If you've got a tablet or smartphone there's an app called Carista, you buy a wireless diagnostic device "elm" and it works through that, it will do the basic reading of fault codes and clearing them. 

 

I'm not a fan of modern electronics, but it's all just another puzzle to work out, so it keeps my brain working. Pretty much an unavoidable evil these days, even my 

CG125 has a CDI unit. 

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cavedweller

Oh yes I too have had to come to terms with electronic ignition finally, but there's a reason. Back in the day when I was a motorcycle courier in London all the electronic ignitions on bikes (and there weren't many back then) were completely shite. They didn't last and cost a fortune to replace. You even had to drop the engine out of a Honda CX500 to do it. Nightmare. So I either used bikes with points ignition or converted my more modern bikes to run points ignition which was easy as most electronic units back then were simply bolt-on affairs that fit where the points on that model used to go.

 

Fast forward a hundred years to now and I'm perfectly happy with the electronic ignition on my bike because it's simple, bulletproof and a spare CDI box only costs me seven quid from China and can be replaced at the side of the road in less than two minutes (never had to though) and everything just works great. If they had been like that in the first place it would have been fine but in the beginning electronic ignition was just terrible so I steadfastly opposed it on my work bikes which had to do hundreds of miles every week in all weathers all the time. Points never let me down, but back then but we didn't have cheap and cheerful Chinese parts like we do now.

 

As for the rest of it, my Polo only has a 999cc engine so anything that robs it of power is no good to me. I know from working on stuff all my life that you CAN get pretty reasonable mileage out of a bigger engine if you try, but an underpowered little engine that's working too hard will still get terrible mileage even if it's a wee little engine. If it's got to struggle along it's just not working efficiently.

 

There's been a lot of waffle over the years since fuel injection became the norm but I can tell you a well tuned carb engine can be as clean running as fuel injection if you stay on top of it and do a bit of tuning and maintenance, but most people don't do their own maintenance these days so a computer assisted fuel injection system that can mostly fend for itself is probably for the best in most cases.

 

It's the primitive nature of this 2000 Polo that drew me to buy it in the first place. Modern cars bore me but there's little actually "modern" about a 2000 Polo and spares are cheaper than bits for my bikes! I hate pretty much all modern cars because I grew up driving cars that had character. In my day a secondhand car could have been anything from the 1940's to the 1970's and cars were wonderful back then. But you'd pay dearly for anything of that vintage now and I can't be bothered to work on them all the time so this Polo fits the bill nicely.

Edited by cavedweller

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dvderlm
17 hours ago, cavedweller said:

There's been a lot of waffle over the years since fuel injection became the norm but I can tell you a well tuned carb engine can be as clean running as fuel injection if you stay on top of it and do a bit of tuning and maintenance

Sorry, but I have to say that is rubbish.

I'm sure you would not claim that brakes or crash cell or suspension or aerodynamics are no better than the olden days. 

 

I know a lot about carbs now. I have tuned Pierburg, Weber twin choke and Dellortos. I've talked with bike carb and SU and Reece Fish enthusiasts.

I've also read the Megasquirt source code from bowling and grippo and discussed with former engineers at PiShurlok and Ricardo.

 

Carburettors do not have 

  • barometric correction (altitude and weather) 
  • temperature correction
  • cold start optimal correction
  • fuel octane or ethanol content correction
  • efficiency feedback self learning
  • inter cylinder optimisation 

At steady state idle or cruise you can get carb and injection to emit the same gases, but the proportion of gas that is not co2 and the unburnt fuel will be higher for

a carb overall because there are at best 4 curves that modulate the mixture based on pressure differences and air speed. When you close the throttle on a carb it temporarily enriches.

I can see this on a logging AFR gauge. A progressive vac-operated secondary throttle plate reduces the effect somewhat but only on second barrel.

An ECU with drive-by-wire throttle can cut fuel supply to minimal or none at overrun. And then inert exhaust gas recirculation and a catalytic convertor can do its trick to catch nitrogen

and use unburnt hydrocarbons. 

 

A well maintained 999cc Polo is a fine thing. 

Save weight any way that does not compromise safety or comfort.


All carbs are compromise, never perfect. 

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Yeti

I'd disagree, I'd say a 2e.. Pierberg is pretty much as near to a perfect carb as you'll ever find, the catch there is they're that complex, no one maintains them and blames them when they break. 

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dvderlm

Bromyard too.

Pierburg 2e2 and 2e3 are things of joy.

 

But I could not get a mini-kat RETRO-fitted to my 2e3 equipped GT, to reduce German road tax.  

 

And the cold idle speed is waaay too high and too long in duration.

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dvderlm

"anything that robs it of power"

 

Check tyre pressures, and switch to low rolling resistance (might be noisier)

 

mytyres.co.uk lets you search by label roll.

 

Hankook kinergy and Goodyear efficientgrip came out well for my tyre sizes.

(continental ecocontact and Michelin are overpriced)

Edited by dvderlm

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cavedweller

Yeah I'm not really happy with the tyres that came on the car, Kormoran (no idea) 155/70-13. When I got the car I thought the ride was a bit squishy so I went and inflated the tyres to 39psi and it greatly improved the ride. Later I even went to 42psi. I'm looking to fit some 14's on the car because I'd like a bit more ground clearance but I'll use these 13's up first. MOT isn't for almost a year so I've got time to look. I know I'm probably technically running "too much" air in the tyres but the difference in the handling is worth it.

 

It was the same with my Triumph GT6. If you ran tyres strictly by the book the handling felt wishy-washy but if you inflated the tyres to about 40psi it greatly improved things, and on a car with THAT suspension anything you could do to make it better was good.

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cavedweller
Quote

I'm sure you would not claim that brakes or crash cell or suspension or aerodynamics are no better than the olden days. 

 

 

Actually that's all a bit relevant. Cars were getting capable of over 100mph by the 1930's and with that also came advances in braking, aerodynamics and suspension etc. Now, granted MOST cars from that era were mass produced fodder for the public to consume, and just like always the public are fobbed off with the bare minimum of what they need to keep the cost down. It's no use selling expensive cars if nobody buys them but you CAN make a "reasonable" vehicle on the cheap and sell it to the masses and make a fortune.

 

Look at the brakes on a high performance 1930's vehicle and you'd see that not a lot has changed. The physics of stopping something is scientific= you apply braking as best you can with the technology you've got, and by the 1930's cars were pretty much sorted out. Now I do admit that there has been advances in certain materials over the years since the 1930's and the actual substance that brake pads are made out of is certainly better nowadays, but that doesn't mean anything much in reality. I've driven 1930's technology and if you're an idiot then yes you will die. But for the sake of argument if you know what's what and understand what you have going on then you can be about as safe in a 1930's car as a modern one because you know and understand what you're working with. This is what I hate about ABS and power steering, etc. It takes the instinctive "feel" away from the driving experience. These days any nump can put their foot down on pretty much any modern car on a motorway and fling it along at 100mph with one finger on the steering wheel while checking their Facebook on their phone, and a lot of numps do that and it kills people. But if you have to be an accomplished  "pilot" of a vehicle to propel it down the road using experience and common sense then you're a better driver. Yes there were certain niggles to be considered with armstrong power steering and drum brakes but if you knew what you were doing you didn't just go out and die, and more importantly you weren't such a danger to other road users.

 

The act of driving a car down the road has become as feeble and as inattentive as sitting in a comfy chair and watching television. and that means that any old nump can and will fling their crappy Mondeo down the road with abandon because the airbags and stuff will save them if they screw up. When cars were more "seat of the pants"  you had to be GOOD or you were dead. These days almost everybody is a piss poor driver because they have never had to learn how to handle a vehicle, it's all assumed to be done by fancy pants computery gubbins they don't understand and let's face it very few people actually work on their own vehicles anymore so they don't even have a clue what they're flinging down the road.

 

My hardtail motorcycle still uses drum brakes of about 1960's vintage and I don't crash into things and die because I know and understand what I've got. I'm well acquainted with the abilities and limitations of my bike and because of that I get along just fine in modern traffic, but I can't count how many times a day I'm nearly killed to death by numps in modern cars who just aren't paying attention.

 

Yes I will concede that certain technology has made the ACT of driving  easier, but I still maintain that it's been detrimental to the whole driving experience for us all. And now that the current mania is for people to have a 200mph Range Rover clone just to nip down to the shops it's the worst driving environment I've ever been in since I started driving way back in the 1970's. The simple fact is that when cars were shit, people were better drivers, but in the modern traffic world you have to adapt to the fact that the roads are full of shit drivers in modern crap cars. I'd still rather drive a 1960's car as a daily hack than anything, but I can't afford the "vintage" cost of running one so I have to do what I can with what I can get, and a 2000 Polo is about as basic as you can get away with these days on a budget. But it still has a bloody airbag light on just because I disconnected the battery to change the starter.

 

Edited by cavedweller

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vwfan3
On 19/04/2019 at 10:17, dvderlm said:

            fuel octane or ethanol content correction
 

Please explain how modern Polos achieve this. Thanks

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vwfan3

Most grateful to you.

I thought on VWs EPC message meant 'Emissions' control, now i know the E stands for Electronic.

 

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dvderlm
On ‎19‎/‎04‎/‎2019 at 10:55, Yeti said:

I'd disagree, I'd say a 2e.. Pierberg is pretty much as near to a perfect carb as you'll ever find …

I found an article from German magazine Gute Fahrt ("good drive") reviewing the 

GT Polo breadvan with Pierburg 2e3 and 75hp GK engine.

 

They remark that since the motor is designed for high revs it lacks elasticity

in the 40-60mph acceleration in fifth gear test, beaten by the five years younger 55hp Digijet injection Polo which 

has more spontaneous feel and smoother idle / low-speed running.

 

Some of this will be camshaft and gearbox, but it shows carbs are a compromise.

 

https://polomagazin.de/index.php?article/35-kraftzwerg-test-vw-polo-gt-mit-75ps-aus-gute-fahrt-12-87/

"Daß ein derart auf Drehzahl ausgelegter Motor keine Spitzenwerte in der Elastizität bringen kann, ist einleuchtend. So sind die 14,6 Sekunden von 60 bis 100 km/h im fünften Gang auch nicht allzu berauschend. Hier muß sich die 75-PS-Maschine gar dem neuen 55-PS-Motor mit der ausgezeichneten Digijet-Einspritzanlage geschlagen geben, die diese Disziplin in 13,4 Sekunden hinter sich brachte (siehe Test GUTE FAHRT 11/87). Beim direkten Vergleich dieser beiden Motoren wird ohnehin mehr als deutlich, daß das neue Motorenkonzept eben fünf Jahre jünger ist, was sich in spontanem Antritt genauso widerspiegelt wie in der Laufruhe."

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