Ok to summarise, g40 in mk1 golf been in the workshop running fine for 2 months in and out, idle perfect never missed a beat
2 days ago ran out of fuel and this is where it all went wrong
Car starts, drives perfectly but will not idle
Parts changed
Blue temp
Co
Ecu
Fpr
Dizzy
Cap and arm
Leads
Plugs
Injectors
3 x idle control valves
Cleaned out fuel rail
Tb
Fitted new fuel filter
Dropped pumps and cleaned out
Dropped some 'petrol magic' in the tank
Checked micro switches on tb with multi meter
Lambda is new bosch and makes no difference if unplugged
All parts removed from mk1 have also been fitted onto running polo g40 and that runs fine with all parts swapped out
Tb gaskets are good
Makes no difference really if blue temp sensor is unplugged
Occasionally runs better with tb unplugged
I'm at the end with this
Any help greatly appreciated
If you lambda isn't making any difference then check the earthing on it plus check the loom for any breaks. Unplugging a lambda should put ecu in safe mode and make the car run a cold start fuel and spark map. Runs richer and will idle higher.
Does it make any difference between hot or cold running?
Earthing point is good and new as is loom
98% of the time sputters and cuts out, the 2% it idles at 2000rpm for around a minute then cuts out
Only from stone cold does it idle ok til auto choke comes of
Nothing changes if you unplug anything really, only tb sometimes
Sounds like blue temp wiring has an open circuit, have you checked all the plugs n loom over?
Check alternator and battery as the sensors get the hump without proper voltage
Checked idle circuit and blue temp circuit
Battery is new and strong and alternator kicking out decent volts
Surely symptoms of a dying fuel pump would be more apparent at wot?
What happens at wot conditions. Everything is ok, or you feel a hesitation?
What's ' decent volts' ?
And what's the co pot set to?
How old is the coil?
Wot is strong all the way to limiter
Coil was new but tried 2 others
Battery seeing 13.5 when running
Co set to 550 and tried 2 others too
How about the knock sensor?
1)Have you checked all the vaccum lines and generally all the hoses that are around the inlet manifold
2)Also check the condition o the inlet mani and throttle body gasket by pooring water while it is working.
3)Have you checked the fuel pressure and supply?
Otherwise, check with a multymeter all the terminals of the loom. It is really weird the fact that doesn't change anything while you unplug blue temp sensor and lamda sensor.
Wasn't aware knock sensor would affect idle
I appreciate the suggestions given so far but must say this only happened when it ran out of fuel
There are only 2 vac lines and no servo on this car, all pipes are new and checked
Had the tb off and cleaned it and checked gasket, usually sucking excess air will always cause high idle
Checking fuel pressure tomorrow
Have run continuenvpcy tests on the loom
I'm starting to struggle to belive anything would have failed at the exact moment it ran out of fuel.....
How old is the tank sometimes with clleaning it out brings up shit in the pipes even tho you've cleaned them out this May have blocked an injector still , but still I'd check knock sensor and lambda
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?
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
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
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?
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
Does anyone have complete pin out wiring diagram for ecu to engine sensors?
If i rev it alot it idles like this
(http://i276.photobucket.com/albums/kk32/ollethalb/mk1%20G40/0D508E5B-DC0F-4B1A-B89A-09B4871A82B5_zpskit9pqb0.mp4)
And after a minute or two starts doing this
(http://i276.photobucket.com/albums/kk32/ollethalb/mk1%20G40/071A8560-5422-4370-AD68-C0BE91303948_zpsbcqcedsn.mp4)
And eventually splutters and cuts out
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 !
What fuel are you using? Gs don't like anything but v power
Old fuel can be bad. But I ran a g daily for 5-6 years on cheap supermarket fuel.
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
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...
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. :-\
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 :(
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