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Worth a try, solved mine by patching up filler neck hole, cutting off bottom of the strainer and putting a huge clear fuel filter on, filled up with sand/crud quite quickly but at least could be seen as was clear filter.Kangaroo got progressively better on the next few months , traded it in about 6 months later , last seen being piloted sideways by next owner around suburbs of chester for months , must have been fine
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Ok, update,
I just cleaned the airfilter box, I'll renew the filter soon too. But just to say I was investigating whether or not this flap valve operated by vacuum, I put it back together went for a very short spin and looked at the flap, the vacuum had sucked it down so that it would theoretically be taking air from across the manifold. The strength of the spring which holds the flap open is incredible and I am amazed the suction was enough to pull the flap down but it did and even with the engine off the suction was still holding it down. I will now pay closer attention tomorrow starting it from cold to see how long it takes to open/close this flap. So this bit appears to functioning ok.
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Update,
The flap valve which was staying openeven with the engine off has stayed open with the engine cold overnight, so it is obviously always open taking air in from across the manifold. I'll look into why a bit later, but I don't see this as a major problem to cause this fault.
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I'm not totally up on the GT engine (1272 3F?), owning a 1043 version. But, looking through the VAG repair manual for this, I?ve found some info ( some of which you probably already know). According to that, regulation is done via a temperature 'regulator' sited in the air ducting, just where it bends 90 degrees downwards into the manifold. Then, as you say, there is vacuum pipe which is connected to the regulator flap.
With the engine running:
- temperatures of above 20 degrees C should have the warm air connection fully closed.
- temperatures of 5-15 degrees should have the warm air connection either partially or fully open.
(I assume it refers to induction air temperatures)
Having said that, you say its open even with the engine off? Remove the pipe from the regulating flap and suck on it to check the ease of movement of the flap itself. It could be that it?s just jammed with a bit of crud.
I'm not sure if this would help, but what would happen if you removed the warm air duct from the manifold when the engine was up to temperature? Then, the engine would be getting the cold air that it was supposed to get when it?s up to temp.
However, I don?t think this is the cause of the problem as this engine has an air temperature sender which supplies info to the ECU, so it should be able to make itself run regardless of induction air temps.
Does it start ok when hot? Is the flat spot also temporary?
It may also be something simple like an air intake leak, as I hear these units don?t like un-metered air entering the system.
(As you can tell, I?m no mechanic, but I hope this helps)
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Your temperature figures are interesting. Basically what they are saying is in Summer daytime when the air temp is above 20 C the flap should be closed to hot air open to cold. Thus in cold weather and at night the regulator should ASAP switch to "open for hot".
The car as it stands, seems to open the flap to hot air straight away and keeps it on hot. This could be due to the vacuum pipes being fitted incorrectly, I;ve been busy today so did not get a chance, tomorrow (Sunday) I'll look at swapping the vac pipes.
P.S. the default position is "open for cold", the vacuum changes that to "open for hot" The mechanism is working, because it gets sucked into the other position.
Does it start ok from hot? Yes, when it's not acting up.
Is the flat spot temp? Yes in the sense that it is an intermittant fault. It's not really a "flat spot" it's hard to describe. When it is acting up and the engine is idling, you accelerate the engine the engine just dies without cuting out, you release the pedal (back to idle position and it wakes up again) if the engine is moving fast and it acts up, then it's like it misses a spark on one of the cylinders and the whole car jumps.
I'm thinking it could be the something to do with the spark/ignition system.
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correction
Does it start ok from hot? I would say on the whole no, this is when the problem starts, after being in a shop for half an hour.
I checked the VAcuum pipes they are on correctly.
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Well at least you've managed to ascertain that the temperature regulating flap is operating ok, so you could pretty much rule that out (I would guess)
I agree that this doesn't seem to be the cause of your current problem and also agree it may be something to do with your ignition system.
Usually, what is the idle like when its hot? Is it smooth and steady or wandering and rough? Is there a miss-fire at idle?
When you say that you have trouble starting after half an hour, do you mean it will turn, but just not fire?
I'm basing these questions on the experience I had with mine not so long ago. It was down to two problems. One was a failing distributor (mainly the hall sensor) and split breather hose.
The car would start great from cold, but once the engine was warm, the idle was rough and lumpy and if the engine was stopped for more than a couple of minutes, the engine just simply wouldn't start. It would take a further 10-20 minutes of 10 second bursts on the starter every so often until it would eventually run. On odd occasions, the engine would miss and surge and like you say, the car would lurch. When the car did this though, the rev counter needle would momentarily flicker wildly from the correct engine revs to 0. This clearly wasn't right because the engine was still turning, but the rev counter said it wasn't! The worst time this happened was on the Forth Road Bridge...scary!
The reason for this was the hall Sender in the distributor. The ECU uses the hall sender in the distributor to tell the injector when to fire, and also supplies the rev counter with data. Mine was failing, so every now and again when the hall sender went on strike, the engine wasn't getting any fuel hence the missing and surging and the rev counter was not getting the data neither, so the needle would be all over the place. Likewise when starting, the hall sender wasn't telling the ECU and no fuel was again, being injected.
Once the distributor was replaced, this starting problem was gone. Really, it was just the hall sender unit that needed replacing, but these aren?t widely available and I was told it was easier just to replace the whole distributor.
However, the rough running continued, with an idle that would constantly wander and occasionally dip from 850RPM to as little 200RPm, but only momentarily. Also the performance was a bit lackluster. This turned out to be a perished breather hose that had split, and was letting un-metered air into the intake system and was causing allsorts of confusion for the engine management. Once this was replaced, the engine idles perfectly, and I?ve had no trouble since.
As far as I?m aware, the Multipoint injection engines like yours use the same principals as my Single point in order to run, but with a few additional sensors, but please, someone correct me if I?m wrong.
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Cheers Roberson,
You just pointed me in the right direction. Took off the distributor and the contacts were badly eroded. Also the hall sender has been broken by a previous garage and is being held on with a cable tie! I had previously not taken much notice of the cable tie on the distributor cap, because the car was running, but now I've got it off I can see there are some serious issues here
New cap and rotor arm definately needed (and might have them in a cupboard already (hope they are the same ones!)
new plug leads, probably not, and probably can't afford them anyway but I'll look into it.
New hall sender unit, probably expensive (how much was yours?) I'll have a look at the price and method of removal.
Found this little page about VW digifant ECU systems
www.volkscafe.com/sp/8691V/8691Vtool.html
I'll get on with this little lot and come back to report in a few days.
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Glad I?ve been of some help horatio.
In an attempt to solve the problem with mine, I had initially replaced the distributor cap and rotor arm, but this didn't help much. I then turned to my local VW specialist who confirmed for me that it was the hall sender unit within the distributor that was at fault. A common problem I believe.
As for the hall sender unit... As far as I?m aware, new units aren't available, so I?m afraid you'll have to replace the distributor as a whole. I had looked for a one for mine, but the hall sender parts were impossible to get a hold of and the guy at my VW garage said they might be available (didn't say for sure) but it would take ages to fit because its a fiddly job. Considering I was paying for labor, he said it was more economical to replace the whole thing. This cost £111. It included a complete distributor and fitting.
Mind you, this did include the rotor arm and cap, so don't waste your money replacing these straight away if your then going to get the distributor changed. It was a simple job and it took them 20-30 minutes to fit.
Having said that, I?ve had a look on GSF car parts web page and hall senders are available for yours but not for mine, and it appears your would be about £55 plus VAT and postage.
Incidentally, I changed the plug leads on mine a couple of months ago, because I was still running on the originals and the spark plug connections were a bit corroded, so I changed them at a cost of £32. (OEM Beru ones) I got those from my garage too, but order them from GSF and they're the same price by the time you add VAT and postage.
I look forward to your report in a few days and I hope it goes well
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Just an update,
I am currently, looking at how to take apart the hall sender from the dizzy body, (seems fairly easy), and also trying to confirm if I have an early hall sender 31 plus VAT or a later hall sender 42 plus VAT. And also I want to see if VAG exchange this dizzy, for cheaper price than 112 plus VAT.
I have found 2 other VW enthusiast forums, to get help from.
It seems this problem is common with VW's and it is not limited to it being any one piece of equipment eg, hall sender, coil or something else.
I have also found out how to read the fault codes so I will be doing that soon too, but I will have to wait until I confirm which wires to connect to in which order.
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Another update:
I have seen blue sparks on the leads, so that is now a *must do*. Hopefully that will sort it all out.
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Not an uncommon problem. I would think that after over 10 years use, the leads would be past their best anyway, mine were.
This, I would imagine, gives quite lumpy idling and quite high exhaust emissions. However, I?m not sure if it would cause the hot starting problems you described earlier, however I would guess its linked to the running issues you described initially in the thread. Either way, if they're arcing, then they clearly not working as intended.
How are you getting along with the distributor?
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I have changed the dizzy cap, because I had a spare in a cupboard. The old one was spark eroded really badly. The new one made no difference to the problem. The rotor arm I had spare was the wrong one (for a normal 1.3 Polo 1987 model) So I'll get one of those with the new leads.
I'm not going to touch the hall sender until I have read / reset & read again the fault codes.....I am waiting for a guy who knows how to do this to give more information on it in a GTi forum called clubgti.com .
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OK It's fixed!
Basically the whole system after the coil was knackered. Plugs, leads, dizzy cap, rotor arm all knackered, all replaced for about 43 quid. Now it's sweet :o)
Thanks Roberson for your help. Btw you referenced the VAG repair manual when you gave me details about the air temperature regulator, was that an online source? if so where is it please?
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I'm glad to hear you've got it all sorted Horatio. I'm surprised it wasn't the distributor that was knackered, since I?m lead to believe this is usually the main cause on Polos of this vintage. But it makes sense to start with the simple items first, like the cap and rotor arm etc and it hasn't cost you much (compared with the price of a new distributor).
The resources on the internet for all Polos, especially pre 1994 editions is quite poor in comparison to those available for the Golf. There was an online version of all parts numbers and diagrams for VAG cars sourced from original VAG databases on a Russian website, but unfortunately, the site is no longer available. Even then, it didn't have 'data' on it, like running temps and voltage tolerances. So, I?m sorry to say there is no online resource.
I got my information from genuine VW service department books which I bought on eBay. Polo info like this rarely turns up on eBay, so I bought it. It?s not a full set of books, which was disappointing, but there is a little bit of useful information in them.
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There's still a few tidbits of info available here, but no polo stuff.
volkswagen.msk.ru/index.php?p=page01
It's probably the site you mentioned.
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