c20let playing funny buggers

[ste porter]

got my let in at last runs realy well pulls hard and engine is silent well happy with it but.......

it randomly heffs blue smoke when it feels like it on idol?
if i pull up at traffic lights some times i get a big cloud of smoke overtake me other times i dont. it can be left idoling for a few minutes and be fine then within a split second car disapears in blue smoke, few seconds later its fine again and it only smokes on tickover and not all the time. Doesent matter if i have been pottering around and not even taken it on boost or if i have just stoped after a full boost run it does it when it feels like it?

oil pressure on idol is 1-1.5 bar temp is around 80 degrees its on mobil s 10w 40 oil and has a 3inch system with no boxes other than a straight through back box so nothing to soak any of the oil thats beeing burnt up
anybody got any ideas

[belly257]

turbo nakard possibly?

[Lee H]

Turbo seals. Is the smoke a whitey/blue colour and really nasty smelling? Clears if you just blip the throttle?

[Will F]

Very common on LETs/KKK's.

Will be seals matey.

[Philsutton]

One of our customers had a similiar problem a while ago, we thought oh turbo has gone ect.... but then we had it on the ramp while it was running and we knocked the oil return pipe and all the smoking stopped.
Changed it for a new one an its been fine since, for some reason it had collapsed and then meant no oil could exit the turbo which in turn forced it past the seals.

[ste porter]

sounds like it phill will take it off and check
and cheers lads i was exspecting turbo seals but thought it would do it constantly?

also its started randomly running lean at cruising speeds when it feels like it but has brought up no trouble codes any ideas on that 1?

[Will F]

sounds like it phill will take it off and check
and cheers lads i was exspecting turbo seals but thought it would do it constantly?

also its started randomly running lean at cruising speeds when it feels like it but has brought up no trouble codes any ideas on that 1?

How do you know? Which AFR are you using?

[ste porter]

it coughs and splutters and doesent run right when the gauge stops reading at all

its not a wide band but it does give a rough idea if im in the right direction of lean or rich

[Philsutton]

If it is smoking its face off then all that crap is going past the lambda, take it out an give it good clean out.

[ste porter]

tryed that phil its now coughing and spluttering in the mornings and doesent want to start from cold very well

[Philsutton]

Do you have another one laying round at all to bang in to see if it makes a difference?

[ste porter]

car starts from cold as normal for a few seconds then coughs splutters and hunts and dies and does this repeatidly for about 10 - 15 turns of the key it will then run realy rough coughing spluttering ticking over at about 500 rpm and touching the throtle doesent effect it other than make it hunt worse
then all of a sudden out of the blue it will just pick up idol normaly and rev ect asif nothing ever happened but when driving it still feels jerky underpowered and hesitant and it doesent fuel properly then it does then it doesent when it likes any ideas. no eml on either and no code logged
so far i have tryed

water temp sensor
lamba
injectors
icv
earths
bigger battery (more amps)
fuel pump
has no air leaks
tested tps and all seemed fine
plugs
dis cap
rotor
coil
coil amp hall sensor thing
knock sensor


im running out of ideas and running out of patience with it

any body?

[ste porter]

just come across something on the auto data should i have a speed sensor fitted?

[Will F]

just come across something on the auto data should i have a speed sensor fitted?

Nope, even if you did, it would only affect the car when driving (cutting out at junctions mainly)

Compression test?

[ste porter]

sorted!!!!!!!!!!

went to pull it in the workshop at home time as i use the van and it gets locked away inside over nite and as usual from cold wouldnt run for more than 5 seconds so i unpluged the air flow meter so it would put it in limp mode and as always ran well enough to pull it in which gave me an idea

the reason i hadnt tryed another airflow meter was because i havent managed to get hold of one for a let but i do have one for an early xe and even though its alot smaller thought i would try it

whala struck up first time purred sweet as and fueled correctly!
drives well now pulls strong and hard and back to full power and good fueling well happy just need to find a maf meter now for a let if any one has one?

thanks for the help guys