Interesting - I just tried to do the same and VCDS complained I have an unregistered version, all of the measuring block fields are red / say not available

im not too good with it myself , maybe someone else can help 

 

unless your polo doesnt have that function

 

theres a few youtube videos and forums that cover the vcds  

I have the full version so I don't know what is available on the lite, but as the boxes were in red does look like they are either not available in the version you have or that your ECU doesn't support them being interrogated ?

It looked like it wasn't available on the version i've got - i'll get a screengrab later today.

 

Got a new problem now...ugh...

 

Yesterday on the motorway while putting my foot down there was a sudden loss of power, like a sharp 'thump', almost like it missed a beat and then got back to 3.5k revs again. Only happened twice so wasn't overly concerned but now when idling hot its hunting around and not holding revs - keeps trying to conk out and then corrects itself.

 

This wasn't present for the drives after the gasket change - all i've done before this particular drive was take the battery neg terminal off, take the ecu plug off, tested some pins with the meter and then plugged everything back in. Oh and used VCDS a little.

 

Pretty miffed - these constant problems are starting to put me off the thing...

 

I'll check for air leaks around the TB and inlet manifold as well as the condition of the plugs etc. Anything obvious I could look for? 

 

I'd start a new thread but as this problem was started by the work to cure the cold idle I thought it should stay here! 

sudden jolt ...id whip the cam belt cover off make sure its still tight and timed up , check the ign timing if you have a light , sort of sounds a bit ign related , did the rev counter drop to zero? 

 

other than that ...sounds like something came off .undone , so check on everything you can think of 

 

i got my working software from ebay , but theres several free versions online you could try

23 minutes ago, steveo3002 said:

sudden jolt ...id whip the cam belt cover off make sure its still tight and timed up , check the ign timing if you have a light , sort of sounds a bit ign related , did the rev counter drop to zero? 

 

other than that ...sounds like something came off .undone , so check on everything you can think of 

 

i got my working software from ebay , but theres several free versions online you could try

 

 

Trust this to happen when I've not got tools in the boot eh... got to get back from Oxford first...

 

The revs didn't drop to zero - almost felt like a stall judder but really sudden and short lived, just a single jolt. Whats strange is it happened only twice - both times when already driving hot and fast and having to put the gas on to keep speed up an incline on the motorway. Power output was standard other than that.

 

I'll have a good old look now before I set off and try not to overdo it on the way home just in case. Hopefully its something obvious...

yeah dunno what to say.....always worth a look at the belt if something wierd happens , if that stays on then nothing terrible should happen 

 

hard to say really ...these random problems are worse than a proper breakdown in a way as if it stopped at least you would find out what it way

 

does it sound okay now?  with it running have a poke and prob on any connectors etc , see if will stumble /cut out

Edited 28 January, 20197 yr by steveo3002

Tell me about it! I find things like sudden stalls a lot more terrifying than an outright breakdown - not nice being put 'on edge' when you're in traffic or trying to accelerate off a motorway ramp.

 

Just drove from Oxford back to Brum and if anything it was significantly worse than last night - started hunting on idle as soon as it started to warm and then cut out a few times in traffic - had to hold a little throttle when stopped to keep things going. Those sudden drops in power happened a few more times and a couple of them were proper judders - to me it felt like a stall.

 

So my theory this this new problem is totally unrelated to anything I've done up till now and just just down to a weak/failing fuel pump or a bit of crud being dislodged in the tank and partially blocking the fuel filter. The hunting idle isn't instant when stopped after moving for a bit but gets real bad if sitting at low revs in traffic. The juddering stall only happens when I put my foot down and appears to only happen after a period of hunting idle or early on in a period of speed (e.g., coming off a motorway roundabout and accelerating onto the on-ramp. This suggests to me that I'm loosing fuel pressure or pressure can't be increased on demand fast enough. It drives fine when throttle position isn't changed and obviously is running fine otherwise I couldn't hold 70mph for hours without incident (so surely ignition and timing is fine).

 

The previous owner said they changed the fuel filter and the old one was 'gross' - could be that last night gunning it onto the M42 I dislodged a bit of crap or it was just a total coincidence and the fuel pump has finally started to have enough. Or possibly that the previous owner didn't in fact change it at all! At least its a cheap thing to try.

 

 

yeah doesnt sound like a silly idea 

 

are the pumps noisey...in my experience they get louder as they get tired , theres 2 pumps , one under the car and another in the tank , you could pull the tank one to check its intake mesh isnt blocked 

 

theres tests somewhere (maybe nige can advise)   bridge the pump wiring and measure the output into a jug

 

id expect a failing pump to possibly make the engine unwilling to rev hard /reach the redline 

5 minutes ago, steveo3002 said:

yeah doesnt sound like a silly idea 

 

are the pumps noisey...in my experience they get louder as they get tired , theres 2 pumps , one under the car and another in the tank , you could pull the tank one to check its intake mesh isnt blocked 

 

theres tests somewhere (maybe nige can advise)   bridge the pump wiring and measure the output into a jug

 

id expect a failing pump to possibly make the engine unwilling to rev hard /reach the redline 

 

Hard to tell what noisy is! But yeah I can hear the pumps (or at least one of them) whine all of the time - can hear it in the cabin and can definitely hear it outside the car.

 

Don't think I've ever redlined the engine, probably 5k at most.

 

my genuine vw pumps a just the slighest purr , cant hear them over engine /standard exhaust...doesnt mean an awefull lot as i had a ebay one that worked fine but sounded like a chainsaw lol

 

id check the strainer in tank and could peer inside the tank too with a torch see if its clean

I figured as much! Easy to get too wound-up with noises, don't often mean much.

 

I'll try a new filter and have a rummage in the tank, fingers crossed. At least its easy to get to the in-tank pump!

 

would have been an ideal time to look at the plugs after a motorway run

 

if you change the filter remember theyre directional

This is the fault finding list on Autodata for poor idling when cold

 

I can’t find a flow rate for the SPI. Only a pressure of 0.8~1.2 bar when idling and holding a pressure of 0.5bar after 5 mins since switching off 

Thanks for that - thats a handy checklist.

 

Well I tried to pull the rider pump but couldn;t get it all out of the hole in the top of the tank - gave it a gentle swish around in case something was stuck to the catch plate, couldn;t really do much more than that (and was getting a bit woozy from fuel fumes!).

 

Changes the fuel filter - I would be very surprised if the one I removed was new in October - looked a bit old to me. With the new one fitted the engine got back to hunting on idle but after some revving to make sure the filter canister was properly filled with fuel and there were no air blockages it seems to be idling relatively happily. Can't tell if its my imagination but definitely doesn't hot idle as smoothly as it did before I changed the head gasket - the timing light shows the tick on the aux pulley jump around between the 0 and -5 degree marks. Still, its a lot better than cutting out! Will see if this stays this way...

 

Only pulled plug 4 to have a look after the motorway today (pulling the others means taking the UFO off the throttle body, couldn't be bothered with that today!) and its a nice clean/light tan colour. Bear in mind that this plug was black when it last went in.

 

Had no end of trouble trying to get VCDS lite to work - I think its the Serial-to-usb converter that came with it. Keeps dropping out and crashing and then won't recognise the mapped port..

 

I'm going to leave this for a while and just see how the car gets on. The lumpiness in the morning is short lived and if the plugs don't foul up and its not drinking fuel I'm not going to worry about that particular problem. If it starts stalling under load or hunting on idle again I'll probably have to enlist a mechanic - I can't be spending all my free time chasing ghosts!

 

Thanks for all the help

are you checking the  timing with the proper procedure (unsure mysellf on a spi)    did you disturb the dizzy when you had the head off?

25 minutes ago, steveo3002 said:

are you checking the  timing with the proper procedure (unsure mysellf on a spi)    did you disturb the dizzy when you had the head off?

 

Following Haynes and all the info I can find online - namely that the timing 'window' is TDC at one end and -5 degrees the other end (counterclockwise). As far as I can tell you just get it to temperature so its idling at ~800 and then set the timing. Rev any higher than that and the timing is advanced out of the window. Just using a standard inductive timing strobe here, nothing swish.

 

I did disturb the dizzy a little when the head was off but re-checked the timing as part of all the checks when I first started it up - the timing mark under the light hadn't moved from where it was before.

 

Theres also that there have been no problems for a good week of driving since the head was put back on - it was behaving perfectly. I'd have thought that any timing issues would have reared their head pretty quickly?

 

 

any mention of undoing the blue sender in your info?  have to on mine but its the mpi version

Just now, steveo3002 said:

any mention of undoing the blue sender in your info?  have to on mine but its the mpi version

 

Naa just run it straight apparently - or atleast thats the info I've had. If you unplug the blue temp sender while warm the revs jump so high i'd have to retard the timing a hell of a lot to get the tic in the window. I've also been working off the assumption that the timing when I got it wasn't too far out - setting the timing to the revs with the sender unplugged would be a real departure from where I am now I think

Edited 28 January, 20197 yr by zob
missing info

I'd start another thread but as its technically the same problem on the same car I thought this should be bumped. However the title should be edited to 'rough running' rather than misfire as I now am 100% certain all cylinders are running.

 

I've done -almost- everything I would have thought possible to cure this lumpy running while the engine warms now. The symptom is really just that - a chug-chug-chugging until the coolant gets to around 70 degrees-ish. I'm confident its something I could live with now but its a little embarassing setting off down the road in the morning! Want to yell out the window 'Its really not a pile of crap! Honest!'.

 

OEM blue temp sensor, ECU gets the correct resistance, good fuel pressure, no air leaks, good spark. When its running rough turning the engine off and re-starting after a little while totally clears the problem - which makes me think its simple over-fuelling and the wait allows the excess to evaporate off while the thermal inertia of the block and head warms everything up.

 

My question then:

If my manifold heater element isn't kicking in would it explain this rough running while warming? The engine runs perfectly for a few seconds after starting and then slowly slides into the chugging until it warms up. I'm guessing the fuelling schedule expects the inlet heater to be running so if its not could this be the source of the over-fuelling?

 

I also notice that the AAV SPI engine uses the ECU instead of a temperature sensor to trigger a relay for the hedgehog - where does this relay sit? Is it the one below the fuel pump relay nestled next to the ECU?

 

 

Thought I would update this problem as I have now found a total solution to the rough/rich running when cold. Having thoroughly browsed the forum I've noticed the symptoms I had cropping up all over the place so hopefully this can be of use to someone else in the future.

 

To recap: Thought it was a misfire but it turned out the ECU (This is an SPI AAV engine) was over-fuelling in the warm-up (temperature-controlled) phase. Sounded like when you forget to set the choke back on a carbed engine. Response was horrible until it warmed up, lots of stink and white smoke from the exhaust, foulled plugs - the lot.

 

Changed the plugs, leads, blue temp sender (new OEM VW one), new head gasket, inlet gaskets. Mucked around with the inlet heater. Tried everything.

 

Today after reading about fuel efficiency and how critical a good earth is to the lambda probe I added an extra earth from the probe's terminal on the inlet manifold to the battery. While I was at it I cleaned the battery terminals and any earth terminals I could find with a wire brush and contact cleaner. Started it up and it idles at 1000rpm from cold, holds it steady and responds like a totally different engine! The smell is better out the back too, no more farting! Couldn't be happier and I'm sure the engine, cat and wallet will be much happier too.

 

So if you've got cold running trouble on an AAV and you've tried all the usual fixes have a look at the condition of your earths! I'm slightly embarrassed that this didn't come to mind months ago when I was trying to fix this - as someone who works with sensor electronics it should have been second nature...

good to hear its fixed...might be worth replacing the earth strap at the alternator too , fattest one you can find