Cutting out at junctions in cold weather

[metz]

Today the polo seems to be cutting out at junctions, been in it for about 30mins with no problems then when i dipped the clutch the revs dropped and it cut out...started straight away but took a few seconds to get back upto 900rpm.

Pulled up at home and a women who had been following me said there was a very strong petrol smell coming out of the exhaust..??

Pulled the blue temp sensor off and idle shot up..put it back on and it dropped back to 900rpm..any ideas guys?

[bstardchild]

Pulled the blue temp sensor off and idle shot up..put it back on and it dropped back to 900rpm..any ideas guys?

I take it the blue temp sensor is the fuel inj engine temp sensor?

Puts on Vauxhall Techie hat and assumes similar system on a polo

If you pull it off it makes it an open circuit so the ECU thinks the engine is fully cold and would increase the injector duration as if it's a cold start so revs may rise in line with fueling.......

Replace sensor?

[metz]

But sensor seems to be working, it idles at 900rpm with it on and flys up to ?? when u unplug it.
Just every so often cuts out when u pull up.

[bstardchild]

But sensor seems to be working, it idles at 900rpm with it on and flys up to ?? when u unplug it.
Just every so often cuts out when u pull up.

OK Plan B

Has the engine got an idle control valve (by-pass valve that links the induction side of the butterfly to the engine side of the butterfly?

[metz]

Is that the orange / red thing in the airbox that has a vacume pipe attached to it?

[SpikeyG40]

i'm having the same problem at the moment! i have a theory that it may be something to do with the induction kit! as it is cold, the engine needs warm air but due to a lack of hot air feed, it just gets cold air. the main resultant in this is whats known as "carb freeze"

other than it being the induction kit, i would be interested to find out also, as i think mine was doing it a bit b4 i put the induction kit on!

metz, can i ask, what petrol are you using? e.g. bp, esso, tesco. and do you do mainly long or short journeys?

[metz]

hiya mate, i use optimax only and do varied journeys really.
I also believe its the induction kit, only does it on cold days or when its freezing at night. if i put some pipe from the manifold to the airfilter it doesnt do it...hmmmm..seems like it could be induction kit not having warm air like u say

Stick a warm air pipe to filter like i did and see what happens

[LogIK]

Doug, when you say "Carb Freezing" I assume you mean Carb Iceing. It won't be this, for the simple fact that our engine is using fuel injection, and therefore carb icing does not exist.

I had the same problem, before I even thought about fitting an induction kit.

I solved it by replacing the blue temp sender and cleaning out the throttle body. Also try cleaning out the ISV.

As for the strong smell of fuel, that will be the engine running very rich, due to it being cold and you having an induction kit fitted.

[Tahrey1043]

well i've been suspecting my own sensors for a while and the car does occasionally ming of petrol, which mates have commented on (more so now than in the summer, which is when you would suspect e.g. the jerrycan would be venting fumes).... maybe my nose has gone numb as they notice it more than me, they think it's reeking when i think it's just detectable!

hmmmm

and when i beat down to bournemouth saturday, including getting lost in coventry and some low speed traffic mixed with a whole lot of battering along with the pedal buried, I managed almost 38mpg --- with it not smelling. wonder if there's a connection. an only occasionally malfunctioning sensor would mean an only occasional smell of fuel, and consumption that might dip down to 30mpg but not the full 17mpg as reported by others.
(or it might just be the wiring)

maybe we can organise a big temp sensor / lambda / earth lead group buy and spend an afternoon comparing to find which ones are working, which are broken, and swapping around


the single point injection can suffer from freeze, as i've witnessed, but it does have a little manifold heater built in apparently which should help on all but the worst mornings, and stop the creeping freeze a carbed car might suffer on a motorway journey.

for the record i have no warm pipe at the moment either - i'm angling to get both a proper hot air pipe and an aerial (and... what else was i after?? argh! oh... i know... filler cap... maybe THATS why it reeks, doh) either from the stealer or a scrappy

[SpikeyG40]

the single point injection can suffer from freeze

bingo! i was right!

[Tahrey1043]

well, it SEEMS to anyhow

maybe not rattling along the m'way (i'll have to try it in december) but it can definately struggle to get started - like frozen dewdrops on the injector?

its nowhere near as close to the block as the mpi ones, and of course there's only one of it

[metz]

Mine will cut out more frequantly if i'm driving at low revs in say 5th gear rather than high revs in 2nd...when i dip the clutch and pull up at a crossing.

[LogIK]

Basically, what I was saying is technically, Carb Icing cannot occur with SPI, as there is no carb!

[Gareth_GT_Hatch]

Cutting out at junctions wont be because of Carb Icing. For a start Like Logic said you guys dont have carburettors. Although the Single point injection system does work in a similar way so I can forgive you for that.

Anyway, carb icing will almost always happen on the motorway after long periods of sustained high speed, or when tring to climb a hill with a large amount of open throttle. And rather that it being a "sudden death" occurrence your car will gradually loose power untill eventually you cant sustain what your doing (i e your foot reaches the floor and youre still loosing speed) Only thing to do then is pull over at the side of the road and let the heat of the engine melt the ice that builds up around the carb jet.

Heres uncle dom's theory on the subject, he's better at answering these sorts of questions;

http://www.porka.net/modules.php?name=X ... &tid=25452

I also agree with logics advice of cleaning the throttlebody and ISV. also replacing the blue temp sensor. Oh and by the way my car runs rich when its cold, Its called a choke. Although on Injection cars its a virtual item

[metz]

choke..i would never have known...

Thing is the car was warm and i had been in it for over 30mins.