UK-POLOS.NET - THE VW Polo Forum

engine problems, i mean. i've now got something thats mystifying me a little.

usually, to go by the behaviour of the car and how it feels to drive, etc, my engine power goes something like this, all the time, even from a few seconds after turning the key when its been standing a week




...but for the past few days (and it definately "happened" rather than blossoming slowly) it's been more like this, from cold (ie standing overnight... needs a couple hours to "settle" before it comes on)



basically i have to make like my batterys flat and keep the revs up 2000-2500 if i want to be able to go anywhere - and i dont just mean accelerate hard, i mean putting foot down without it slowing down. in 3rd. on the flat... even higher if i'm pulling off, because if it bogs down on a difficult start, that's it, there's nothing left to rev it up with unless i stick the clutch right down and wait a few seconds, which makes turning right either a very hairy or a very noisy/smelly experience. even in neutral the effect is very noticable... even trying a fairly mild throttle setting the response is noticably slowed, and if i punt it... splutter splutter... then a very, verrrrry slow rev-up until it hits that magical speed and goes vrrrrrm

after 5 minutes driving or so, even if i go say 3 minutes then park up for 3 and re-start the engine that's enough, it goes away, but it feels like forever.

what might be causing this, whys it come on all of a sudden, and any ideas how i might fix it guys?
highly annoying! and a little dangerous too!

(it's like i'm driving a manual choke carb car and never pulling the knob out to richen the mix or something... except it's idling well enough, only slightly rough..)

whats the state of your senders? have u changed them l8ly. Have u got a induction kit on?

Sounds like my car for the first few minutes of running on a snowy morning Hellish to get going like that..

I'd put it down to a failed automatic choke, if only you had one All I can think of is this lot though:

Is it running on all four cylinders?
How recent are the plugs / leads?
What condition are your various senders in?

All cylinders - yep..... when it gets to the point where it's slowing down, it becomes no cylinders (basically its like it's on overrun, or ive turned the key off.... have a feeling that if i clutched down then, it would stall right out)
it occasionally feels like one or two miss beats, but feels more like a symptom than a cause.. its a "smooth" loss of power, if you get me, like driving with the handbrake on.

Leads - pretty new. Proper jobs from GSF as well....

Plugs - um! Well considering the car hasn't had a proper service for a while and i've been sorting these things out myself instead, guess i should at least pull em and have a look

Senders...... que?

Probably them as i'm a bit lost on which ones you mean... hall, temp, oil pressure, lambda, something else? Whichever they are, take it as read that, like some kind of fruit, i've never touched em.. bit worried that i'd never get em back in without breaking them and all that

guess i'll have to go off and check these things out before getting any better help or diagnosis as a quick guide, which sender/s did you mean, and would it be immediately obvious they're busted? Or is it a case of getting a new one, putting it in, and seeing if that maybe solves the problem?

tis just wierd how this comes on from very-cold and not at any other time..

mine does lots of wierd things when it's been left overnight like warning lights coming on, ISV playing up, temperature guarge sometimes works.
But then, like you say 3 minutes into the journey, if you stop and start the thing.. its fine...

My Mk2 Golf used to do it aswell...

the ones down under the dizzy. The blue and black one (I think), I've never toutched them myself but (someone correct me here if I'm wrong) it's just a case of pulling them out.

They would be the thermostat senders, and yeah, they sound likely.. if it's only happening from cold, I'd guess that the thermostat's not registering that it's cold and so the ECU isn't compensating for it.. it'd have the same effect as an automatic choke failing and not closing when it got cold. Might also be worth taking the thermostat out and testing it (stick it in a saucepan, heat it up, watch for it to open). It's not difficult to remove, and you're highly unlikely to break anything by doing it

[quote="Tahrey1043"

Leads - pretty new. Proper jobs from GSF as well....

[/quote]

are they genuine leads?

Sounds like the blue temp sender to me. Its easy to find, like dan says its underneath the dizzy (in the thermostat housing in fact). Its about £8.50 plus vat from vag for a new one but alot cheaper from GSF. Change and try! Or if youve got a multimeter, check out the polo GT website, theres an article in there about temp sensors and breaks down what resistance it should be at what temperature.

that's cool, when I was at BVF a few people were lookin at the engine, and someone noted the size of my dizzy...


The guy changed it when the dizzy went in the car afew months back and no-one on porka could easily identify what it was. The dizzy was aparently from a Golf and it worked. Think it was a good thing?

well apparently the polo's supposed to use the same one as a 1300cc beetle, so who knows!! just how big IS yours?

cheers guys, i was suspecting something like that, but of course....not quite bright enough to make the connections or pin it down
might be a busted wire on that sender or something i'm thinking - it's only playing up occasionally, like a knackered phone charger lead or something. EG today and yesterday, it hasn't done it, nor friday, but all the days inbetween it has... no predicting when it might happen again.

sounds like an easy, cheap alternative to having the car stand idling for 3 minutes while i get all my stuff ready to put in it and drive off!
(thermostat.... housing???)

the leads are "Beru" or something like that - apparently the type and brand used as OEM gear when the car was made. dunno if that's much of a reccomendation mind, but they fixed the problems i was having and this seems different.

time to grab the haynes, and that multimeter out of the box in the cupboard (£2.99 from Lidl, bargain - its helped with so many things)!

and then... onwards to sorting these clocks out

They way they go wrong is pretty random anyway, one day theyll be fine the next theyll be totally screwed and the day after be fine again. I doubt its a "busted wire"

ooo! fun!

haynes says i need to do... well.. a ton of stuff. basically "drain most of the coolant out and have a fresh O-ring and lots of paper towel on hand"... which involves clipping pipes off at the radiator and scary stuff like that

so instead i decided to play with it another way, before i can find the multimeter: i just unclipped the plug from the sensor and saw what difference it made when i made and broke the contact.

well, it certainly ran differently. a little bit of a different idle speed and throttle opening (cant remember which way! even tho i had filter off to watch) when unclipped and a little lumpier to rev up... or mebbe the other way round... tho certainly not the same problem as before. mind you the engine was of course warming up all the time!
and then just as i'm ready to go "hmmm, well, that was interesting but fruitless", something was felt to shift as i was clipping the sensor back on for the final time... and the engine just went for it. i think it (probably) only revved up to about 2000-2500, but the noise from that while standing right over the block was enough to make me sh*t a brick and run round to kill the ignition

quite bizarre... whatever it was had fixed itself by the time i restarted the engine and i couldnt repeat the result - think its a definate sign of something being amiss there though! like a wire shorting out? definately grab the multimeter and test the resistances with a stone cold, half warm, and running-temp engine.. with mucho wiggling of sensor

suppose the coolant probably needs changing along with the brake fluid anyway, its likely not seen the light of day while ive had it even with "professional" servicing, and maybe not even all the time it's been around... may as well make a job lot of it... change coolant, change sensor, replace brake fluid, adjust the shoes.... top up gearbox?

right, found the meter, not sure if THATs working right either but will try testing the resistance of some fuses and things first

cheers for the link with the numbers in gaz, i can at least try it with the engine cold, engine warm.. possibly bridge the plug contacts as well, see if that causes the same uber-fast idle! (hmm!! DIY cruise control anyone?)

from the look of the figures, having the sensor disconnected (or broken) should cause near-infinite resistance - or in other words, make the ECU think that it's about -40 celcius.. hence "diagnostic mode" hmm... praps it IS a shorting problem (ZERO resistance... about 150'c )

also from that page... mebbe its a dodgy coil