Losing the plot - anyone who can suggest a fix for this is my hero

[z3i]

Knock sensor won't affect idle! It's not even in use then

Fuel filter would filter out any crap so wouldn't even reach the injectors

Were you giving it some when It run out of fuel?

[olethalb]

the car has run fine for 2 months in and out of the workshop - left idleing for an hour at a time sometimes, nothing changed until it ran out of fuel

didn't think knock had anything to do with idle but been a long long time since i got involved with g40 stuff, mainly 1.8T and tfsi these days

i went to rev it, it bogged then i booted it to the limiter then it bogged and sputtered ( had no dash at the time so was unaware of low fuel) nursed it back into the workshop - threw £2 of fuel in and fired straight up

[olethalb]

Ok swapped both fuel pumps

Still stutters and doesn't idle but when i remove blue sensor plug idle raises to what sounds like 1500 and when i unplug lambda idle raises to about 1300 by sound

Tried another throttle body and gaskets

Checked fuel pressure, steady 3 bar

13v at battery on idle

Only thing i haven't swapped is lambda

[Etches]

May aswell change the lambda whilst you are here lol.

Sounds like blue temps working (is it a new vw item?)

Have you checked the dizzy timing again now and set it with blue temp unplugged?

[olethalb]

yea set timing 3 sensors now, original, new topran and new OE all do the same, lambda is brand new bosch - i don't want to buy another haha

[olethalb]

Does anyone have complete pin out wiring diagram for ecu to engine sensors?

[olethalb]

If i rev it alot it idles like this



And after a minute or two starts doing this



And eventually splutters and cuts out

[brownysblower]

Sounds like your alternator may be faulty
Producing ac current !! This will fire injectors
Randomly
Have you got a spare one to try
Ps check earth strap from charger to chassis
Has a good clean contact !

[Ben.lopo]

What fuel are you using? Gs don't like anything but v power

[PeteG40]

Old fuel can be bad. But I ran a g daily for 5-6 years on cheap supermarket fuel.

[olethalb]

thanks for the replies, as stated earths were new, after it ran out it had £50 of optimax, alternator was tested

**PROBLEM CURED - brand new bosch lambda had crapped out, fitted another lambda and ran perfect  **

thanks for all the suggestions, hopefully this can help others in future

Olly

[Lionheart]

Had same problem recently where Bosch lasted 3 months after rebuild, really screwed up engine mgt, new lambda went in after doing most/all of the things you tried and sorted it! 
Good to hear you are back rolling...

[randombadger69]

Could suspect fuel has caused this? Or is it more likely a bad batch of sensors.

Have replaced lambda sensors in both my Gees recently with Bosch ones. 

[olethalb]

thanks chaps

well there was probably £5 - £10 that had been in the tank for 10 years

before first start had £20 of optimax

then £30 of optimax

unfortunately had a mate bring me some fuel when it was running low (£50 of fuel idling haha) and that was £30 of tesco's finest cheepo crap

after it ran out on that (no dash installed) thats when it went boobs up

chucked £50 more optimax in it but obviously lambda had passed away by that point

[youngprodigys]

You more than likely killed the lambda sensor yourself! rather than it being defective. You said previously that no dash was installed so you couldnt see the fuel gauge - in doing this you will have ran without a D+ exciter signal to the alternator. Without the alternator charging the battery combined with the large drag on the crank of the supercharger you will have been running at less than the Digifants required 12.5V. This triggers the Digifant to run in default mode and will overfuel the car (even at idle) always run the alternator mate!

Plugging the car into the diagnostics will have pointed you in the direction straight away - i recommend you buy yourself a vagcom 409 lead, a 2+2 adapter and run vwtool as this is a known compatible problem to diagnose the G40s Digifant system.

KiZ