G40 issues..

[bmxthrash]

First of all hi, this is my first post on here after buying a mk3 polo cl 1.3 with a G40 convertion!

When i bought it it had a few small running issues which i've managed to sort out, such as new coolant sensors both blue and black and a sorted out the air flow sensor on the boost pipe!

Since doing that, its started running very lumpy again at low revs and smelling very rich inside the car.
When im sat in traffic or at lights the revs drop and the engine cute out.  This also happens when I'm changing gears either up or down when I'm driving sensibly!

Engine wise its had a 65mm pulley and chipped with a de-wedged throttle body, thats pretty much it if that helps at all?!?

could this be a simple new lambda sensor as its running very rich and over fuelling and making it stall?!?

Any suggestions on this could be and how it could be fixed would be great

cheers iain  

[DKnight]

howdy and welcome

well the lambda sensor issue is simple to check, next to the throttlebody it connects so just unplug it, and see how it then idles.

Also the air flow sensor i guess you mean the co2 pot? if this is new or a replacement it will need setting as someone may have fettled it, there is a guide on here somewhere, a multimeter can tell you what readings it should give but the accurate way is to get it on a gas analyzer.

Where did you get your new blue temp sensor from? as i have seen half a dozen faulty new ones, a very common problem.

The blue temp sensor works very similar to the lambda probe, and can cause the same problems.
Once the car is up to temperature, unplug that and see if it again alters how it runs. (it will not start if you unplug it from cold)

See how you get on

[bmxthrash]

Hi thank you for the reply 

It could be the Co2 pot yeah or Co sensor?!? i know its the only sensor on the boost pipe haha
I didn't replace it no, the previous owner had lost the clip on it and had zip tied it on but badly and i hadn't noticed so it was wobbling all over the place, so now its in securely!

As for the blue sensor i bought it from VW them selfs rather than a gsf or eurocarparts piece so im hoping that won't be a problem! its also helped the running of the car since changing it!

If the lambda is shot whats the best one to buy?!?

cheers for the help 

[hayesey]

I'm not so sure it's going to be the lambda probe if it's dodgy at idle too, as the probe isnt being used at idle.  Problems like this are notoriously hard to find because there's literally 100s of things it could be and it's fairly impossible for anyone over the internet to diagnose.  Have a read of this FAQ to get started on diagnosing and hopefully ruling things out one by one, it's a process of elimination.  You will need a few things such as a multimeter and a vagcom lead.

[hayesey]

also, you need to get the CO pot set correctly as that will affect the fuelling.  Only real way is on a gas analyser but setting it to about 550ohms is usually a reasonable base setting.

Here's the link I forgot to post by the way!

http://www.polog40.co.uk/forum/index.php/topic,214.0.html

[bmxthrash]

Yeah ive been reading up on that post and its very helpful, ive gone and bought a multimeter and im currently on ebay buying the leads for vagcom hopefully this will help!

where can i get it gas analysed?!

cheers guys 

[hayesey]

any garage that does MOTs will have a gas analyser

[bmxthrash]

ahh i should have guessed that!

cheers for the help guys i really appreciate it. just want my car to run smooth and proper! 

[bmxthrash]

only had a few mins with the car tonight and unplugged the lambda sensor..this made no difference. .I dont know why i looked at the ecu, but when i did i realised my mate telling me about a vacuum hose that runs out from it and it must be 1m long or you get serious running issues, mine was under 50cm! i unplugged it and it ran slightly worse than when it was on but still kinda the same if what im saying makes sense?!?

so maybe this could be one of the problems?!?

[PeteG40]

1m long is for the g60 not g40.

[bmxthrash]

ah ok, how long should the g40 be?!

[bmxthrash]

and how thick?

[cheys03]

it should be 500mm (50cm)

[bmxthrash]

well today ive done a few things like made sure all the earth wires are clean ect, managed to snap off my washer mechanism so i now have no windscreen washer (never used it anyways but theres a huge gap there now haha) put in a temporary vacuum hose to see if it was that, re-attached the lambda sensor, then unplugged it again to see if anything was different, pulled out the spark plugs to find them very very black and very very furry! so yeah that means i have a few reasons why its not running right ie Air/fuel mixture too rich, electrical problem, plug heat range too cold , carburetor problem - float level high, defective needle or seat, weak ignition voltage, an inoperative preheating system (carburetor intake air), or extremely low cylinder compression.

is how im feeling

to the garage it goes 

[hayesey]

carburettor problem!?