I'm not sure I'm going to like the answers I get to this question but here goes.
My Zetec installation has started producing large quantities of blue/grey smoke when it is cold. Once it has reached running temp it seems fine.
It seems to have happened since I got the megasquirt tuned to an AFR of 14.7 : 1 at idle with a hot engine and got the fast idle valve working.
I know the diagnosis of blue smoke on overrun but what could be causing this blue/grey smoke during warm up?
Is it oil or mixture?
To be honest it doesn't smell oily.
Thoughts please.
Too rich ?
Clearances tightening up once warm stopping oil getting past seals ?
Burning oil off that as got passed seals whilst stood ?
dunno
[Edited on 2/5/06 by Jon Ison]
Does it have a cat fitted ?
It could be too rich I guess as it happens when warm up enrichment is active (efi equivalent of choke) but as fast idle is also active which allows extra air past throttle I thought this was unlikely.
valve guide oil seals perhaps?
quote:
Originally posted by UncleFista
Does it have a cat fitted ?
TBH then, it probably smokes all the time, once the cat warms up it'll clean the exhaust and the smoke will dissapear
quote:
Originally posted by Wadders
valve guide oil seals perhaps?
quote:
Originally posted by UncleFista
TBH then, it probably smokes all the time, once the cat warms up it'll clean the exhaust and the smoke will dissapear
They are fitted on some diesels, to do just that.
Will a cat do that?
I didn't think they would remove smoke like that.
So the concensus seems to be the engine is fcuked and the cat is removing the smoke.
This leads to the next question.
What has happened?
Bearing in mind that this has only just started happening and the car has not yet been driven in anger.
When the engine was first started it was running rich but there was no sign of any blue smoke. I have done some preliminary tuning and driven the car
in first and second gear.
I don't think that I could have damaged internals by running lean and overheating.
What do you guys think?
Can you take your cat out and see if the engine smokes all the time? Or isnt it as simple as that?
I would go with the stem seals are knackered (very cheap to replace) and that oil is running into the cylinder. Either that or its running very rich
when cold.
Had an old astra that produced blue smoke when started but was fine after running for a short while - changing the stem seals fixed it. The oil gets past the seals as it sits and then burns off when started.
Could you have put too much oil in???
Sounds like its running rich and burning excess oil off to me. Worst case will be valve stem oil seals.
Try a compresion test. If upper wear is suspected i think you can get an additive that will reduce it for a while - at least this will help to
diagnose.
Ive overfilled mine twice now. Head was completely refurbed so i know it is OK. After a while it settles down when oil reaches better level.
Dont think the worse - maybe finish the car and take it for a good run out, it may sort itself out. Could it be something daft like sticky lifters or
valve seats slightly corroded when standing - these should sort themselvesout after a few miles. Give it a thrashing and see what happens.
Thanks for the answers guys.
This is starting to get to me now.
I have SVA booked for next Friday and I just keep finding new things that are going wrong.
I think I'm going to have to investigate further what is causing this smoke.
Hopefully a compression test should give me some clues whether there is any internal damage or not.
Removing the cat is an option, to see if it is the cat removing the smoke when it reaches opperating temp or if the engine itself stops producing it
then. This wll however involve making up a new pipe that I haven't really got time to do.
I'm pretty certain that it hasn't been overfilled with oil.
What I'm struggling to understand is why it has suddenly started happening.
The engine has certainly not been put under undue stress or over revved.
It may have been running lean for short periods whilst tuning, but not under high load conditions.
Did you get chance to see the engine running before installation? Was the engine standing for a long period before fitting in the kit car?
I very much doubt that you have done anything to cause the smoke after such a short time period.
My Dads engine (xflow) had a problem with the valve seats at first. When left standing some of the valves will be in open position and may not seal
fully at first. His has sorted itself out after a few miles (1,000 or so).
Id be tempted to put it all together and go for SVA as it is and see what happens. From experience it is tough to pass first time so worst case you
will get a job list. This will buy you some more time to investigate what is happening. Im sure if you suspect valve stem seals there is an additive
you can use. my local trade place was raving on about the Forte range of products (i bought some coolant flush).
I wish i could be of more help. Best to not panic for now and just check out the basics. 2 things i found:
1. When running rich it the pinto was smokey but more of a greyish black colour - sorted at local garage on the emissions tester.
2. When i overfilled slightly i got a lot of smoke when accelerating hard, particularly coming out of a junction. Oil was at the top dipstick mark -
not over. Im running a modified sump so oil level has been a bit trial and error. Reason i ran full was to avoid any oil surge but this appears to
have been counter productive.
My first thought is the valve stem oil seals.
To check this run the engine up to temp then turn off and leave over night. Take off the exhuast manifold and look down the ports with a torch. If you
can see oil on the valve stems running down onto the valves that's your problem.
My Pinto ran fine before I let is stand for the winter. The valve stem seals perished and actually fell to bits. I used 1/2 the oil in the sump up in
a few miles making a james bond smoke screen. Couple of quid for new seals and it's perfect again.