g40 engine weird cold start running ??

Oli b · April 11, 2012, 07:50:58 PM

when i get im my car in the mornings start up runs fine for 5-10 seconds then starts running on 3 cylinders for 10-30 seconds or so depends how cold it is then clears and runns fine boosts as it should no blue smoke either(once warmed up properly) and doesnt use much oil like a liter a month ish if i start it up when its warm outside its fine no running on 3

any ideas what it could be or what to check

cheys03 · April 11, 2012, 07:55:46 PM

Litre of oil a month?!

Oli b · April 11, 2012, 07:57:10 PM

depends do like 3-5 k miles a month tho

Oli b · April 11, 2012, 08:00:28 PM

proberly bout half a litre now i think about it

cheys03 · April 11, 2012, 08:32:12 PM

Lot o miles!

Give this bad boy a go for starters - should uncover most faults:
http://www.polog40.co.uk/forum/index.php/topic,214.0.html

Please can you list your full engine spec

cheys03 · April 11, 2012, 08:39:10 PM

If you have a Wideband AFM, what does it read when it's spluttering btw? If it's a tad lean you could use the CO pot to richen it up - start with half a turn clockwise and see if it helps. Equally half a turn anticlockwise if it's too rich (be careful of lean misfires though which can look rich as the unburnt fuel is dumped into the exhaust).

Oli b · April 11, 2012, 09:12:32 PM

Well its my daily driver engine spec is
Standerd g40 head and block
Gt inlet
Dewedged tb
Stage 4 jabba charger
65mm pully on twin v belts
Standard boost return setup
Jabba chipped ecu
Standard mani and down pipe then into a 2inch bore magnex 8v gti exhaust system
(lumps in a mk2 golf btw)
Yeah gotta afr wide band and it runns verry rich about 10:1 on cold start up wich goes to about 12:1 once its sorted its self out then gradually leans as it gets warmer Ill have a play with the co pot one morning see if it can make a differance to the afrs

Jezza-7 · April 12, 2012, 01:06:00 AM

Thats over fuelling a bit. Mine on boost is around the 11's.

What are you plugs like? What ones you using?

hayesey · April 12, 2012, 09:23:55 AM

he's saying that's when it's cold though so I'd probably ignore cold AFR readings.

Have you got the standard chip? Does it run any better with that?

PeteG40 · April 12, 2012, 11:49:24 AM

'd be checkin boost pipes didnt have excess oil - that it burns off when warm.

also i'd check thecompression. My mums 1litre chugged like hell when cold when the head gasket was on its way out.

Chris_J · April 12, 2012, 06:20:08 PM

My current G does this too (low miler on 58k), my old G and my GT engine that I rebuilt all did exactly the same thing. I never got to the bottom of it and I kinda just live with it.

I have noticed that when my G does it now, there's a slighter more than normal amount of smoke that comes out of the exhaust. Only lasts for about 15 seconds and it clears, running completely normal after that.

It still bothers me in the back of my mind, so I'm watching coolant levels, as TBH I suspect the head gasket. So far though, it appears to be using zero coolant.

Something I'm going to try next which you may want to do - Start her up cold and let it misfire. The second it clears, stop the engine and whip the plugs out. You may find an unusually fouled or steam cleaned plug??

Chris_J · April 13, 2012, 01:42:42 PM

Did the test last night that I described above. All plugs came out equally heavily carbon fouled, no other unusual deposits or fouling.

I'd maybe put this down to it running very rich at startup, however, does this both with stock chip as well as the PPP one.

Oli b · April 15, 2012, 02:22:27 PM

Thanks for the replys guys
Had a look over it all this morning Took the boost pipe off to check how much oil is there and found

And most of the pipes and intercooler have a light greyish film of oil
I have genuine vw g40 spark plugs and they all looked the same

Took the dizzy cap off and was a bit dusty inside so cleaned it all out
Put the plugs back in and boost pipes back on and it started fine from cold
No misfireing :/ also got a exhaust leak at the manifold to downpipe join wich is why my exhaust has been so noisy

I havnt got a standard chip for it so cant try it

PeteG40 · April 15, 2012, 04:53:37 PM

thats quite a bit of oil in the system! i'd say why your using it. Probably a weaping charger oil seal.

Oli b · April 15, 2012, 05:14:46 PM

Quote from: PeteG40 on April 15, 2012, 04:53:37 PM
thats quite a bit of oil in the system! i'd say why your using it. Probably a weaping charger oil seal.

yeah was a bit more than usuall, and noticed if i drive it off boost for 100+miles then use boost it blue smokes for a little bit then stops smoking so i quess this is all the oil thats getting stored in the intercooler and piping geting forced into the engine