Running problems

[jimbugalee]

Hi everyone,
I have a 93 g40 py engine code but i've been having some running problems, it has lumpy idle and cuts out at junctions. In the past fortnight the below jobs have been done:
Super charger overhall at jabba sport
Heads been overhauled with new guides,valves,and a skim.
Genuine coolant sensors including the blue one!
All top end gaskets (genuine)
Plugs,leads.cap,rotar arm
New fuel tank
Cambelt water pump
The timing has also been done and I've triple checked it.
However after all of this it still runs lumpy and cuts out at junctions, its worse when its cold. When you restart after its cut out in the morning it turns over slow like the timing is really far out but its not.
Also when I connect vag com the live data says its 5860rpm when its idling (900rpm) I think its something to do with this but if anyone has any ideas it would greatly appreciated.

[PeteG40]

get a multimeter and check your co pot and the output of your alternator...

i'd say the alternator was probably on its way out, not supplying enough voltage or the battery is dying and therefore the car is running in limp home mode.

[jimbugalee]

Thanks mate which wires on the co pot do i check do i adjust it 5.50 ohms?

[G4O LP]

gemma sorry i didnt get back to you earlier but i would of said the same as pete anyway. Hope you get it sorted. Mine just needs an MOT and tax which frustratingly I cant afford at the moment lol

lew

[PeteG40]

550 ohms  ish

[hayesey]

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

[jimbugalee]

Hi all,

Thanks to everyone for their help.  I got Dean to type up this original post as I don't really know the technical side but he's read through everything and we're going to try a new alternator first and work from there.

We'll keep you updated!

Gemma

[jimbugalee]

Hi again all,

Had some great news from Dean that after a new alternator and a clean up of all the earth wires (think that's what he said?!) that the G seems to be running well now.  I am so chuffed and grateful for all the work he put into it.

It's gonna be a like a new car when I get it back!! Can't wait .....

Thank for everyone's help on here and Phil   Gonna polish it all up this weekend and take pics hehe

[Dan]

Yes, it's amazing what difference a good alternator and clean earths make !

[jimbugalee]

Maybe I spoke too soon.  The G still isn't quite right.  It's hunting a bit and has cut out a couple of times when driving and braking.

I'm going to drive it about this weekend and see how it goes but we might have to come back for some more advice!

Thanks all

Gemma

[jimbugalee]

Hi all,

I've now done the run in miles (just over 400) on the G40 and it STILL won't idle and keeps cutting out.

I think it's a little bit worse when it's cold.  Sometimes it's perfect and will sit there, othertime it will totally drop revs and die.  Also when I pull away it can't seem to take me accelerating and can't pick the revs up, then again cuts out.  Still cuts out when you come to a junction as it can't hold the revs.

Any more ideas?!!!  It's such a shame as I've waited ages to get it back but I can't really drive it like this.  Thanks for all your help everyone.

Gemma

[samg40]

Its nothing as simple as the idle screw on the throttle body is it? Thats given me terrible idleing etc in the past. Worth a try.

[dannyb.G40]

jimbugalee if you get this fixed can you let me know cos i have exactly the same problem!

Its as if there is a vacuum leak somewhere, but i can't find one! I've replaced the blue temp sender and lambda (although the lambda was from gsf) and nothing seems to help.

[jimbugalee]

See above for some of the things I tried Danny.  They did help but the latest is that it will idle fine when I turn it on from cold although it is hunting at bit and if I leave for 5 mins it might not hold and will stall.

If I drive it when it's cold I might as well not bother as it will permentantly stall (not my lack of driving skill!).  When you pull up it can't hold it's revs .. just drops to idle and then drops off completely and stalls.  Definitely worse when it's cold but still not right when it's warm.

I'm going to take it back into Dean and expect he'll come back on here for some advice as we're a bit stuck.

[DKnight]

hmm it sounds like you have very similar problems to me, if you check my other post below

i swapped the blue temp sender today and it fired straight away


but then i fitted it, tried again and it still had starting issues, so this makes me think its a wiring fault to the blue temp sender, so im going to check that its working right no loose connection

you want to put a spare blue temp sender in some hot water, and then take that to the car and fit that and fire it up and see how it effects it

just an idea, what im gunna try! aswell as checking all the connections