White smoke on startup

Post by **Jeff jones** » Tue Feb 22, 2022 4:21 pm

Hi all, i have a 1995 2.0 16v Ford Probe that smokes like Thomas the tank engine on startup. I have reconned the head but it still smokes, It is clear after a short distance and flew the emissions on the mot. Any idea what could be causing this?

Post by **Micron** » Tue Feb 22, 2022 4:40 pm

Jeff jones wrote: ↑
Tue Feb 22, 2022 4:21 pm
Hi all, i have a 1995 2.0 16v Ford Probe that smokes like Thomas the tank engine on startup. I have reconditioned the head but it still smokes, It is clear after a short distance and flew the emissions on the mot. Any idea what could be causing this?

How long ago did you recondition the head?, did you do the valve stem seals, although it's not normally the problem? Have you ever done a compression test to see if you are loosing a bit past your piston rings and letting oil in to the bore?

Post by **Kit** » Tue Feb 22, 2022 4:55 pm

I’ve known modern oil’s to wash the carbon build up from the rings, at oil change time.
This lead to some white smoke, till the carbon builds up again & makes a better seal on the cylinder wall

Kit

Post by **Sunfly** » Wed Feb 23, 2022 9:36 am

Not sure if this the whole story or even relevant with a probe but from my distant marine engineering days we spent a lot of time watching smoke and the menu was...

White smoke - too much air (a lean mixture of air and fuel)
Blue smoke - burning oil.
Black smoke - not enough air.

So on that basis I would check the air induction system as you've had the head off, maybe the VRIS (2 of them) are open when they should be closed etc. The above would always hold good for turbo charged diesel engines but its difficult to see how a naturally aspirated petrol engine might get too much air other than a VRIS problem if the injection system was OK.

Be wary of white smoke. It means a lot of heat in the exhaust gas which can mean damage to valves etc.

With a diesel it was maybe a sign of fuel of some kind burning in the exhaust belt and surging the turbo's so not good at all. With Napier turbo's that source was possibly the blowers own lub oil system causing a runaway. Obviously not relevant here, but interesting.

Post by **jrh** » Wed Feb 23, 2022 10:49 am

As above , plus it may just be water vapour , quite normal to see it at start up but , if it persists , then guess where the excess water is coming from ?
Observing the exhaust of the jet engine at height is a wonderful visible demonstration of what happens , but you don't see , at ground level.
Burn 1lb of fuel, create 10lb of water , can't avoid it.

Post by **Jeff jones** » Wed Feb 23, 2022 2:44 pm

Thanks all, the head had a full recon about a month ago and it was noted that the piston had a slight movement. with it being an old engine with a lot of miles it was thought ' as to be expected'.
I will check to see if too much air is being inducted but the smoke stops after about 20-30 seconds and the exhaust is clear of any smoke until the next morning.
I have read that an injector might be the culprit, il dig some out and give it a try. Thanks all for your imput its given me a few things to try out, Cheers all.

Post by **Micron** » Wed Feb 23, 2022 3:46 pm

I'm interested to understand how an injector can cause this?

Post by **Jon G 24V** » Wed Feb 23, 2022 4:15 pm

Micron wrote: ↑
Wed Feb 23, 2022 3:46 pm
I'm interested to understand how an injector can cause this?

If the Injector was faulty and not opening up enough or partially blocked then it cause lean running ie to much air and not enough fuel

Post by **Micron** » Wed Feb 23, 2022 4:54 pm

Jon G 24V wrote: ↑
Wed Feb 23, 2022 4:15 pm

Micron wrote: ↑
Wed Feb 23, 2022 3:46 pm
I'm interested to understand how an injector can cause this?
If the Injector was faulty and not opening up enough or partially blocked then it cause lean running ie to much air and not enough fuel

And does that cause white smoke?

Post by **Sunfly** » Thu Feb 24, 2022 8:00 am

jrh wrote: ↑
Wed Feb 23, 2022 10:49 am
As above , plus it may just be water vapour , quite normal to see it at start up but , if it persists , then guess where the excess water is coming from ?
Observing the exhaust of the jet engine at height is a wonderful visible demonstration of what happens , but you don't see , at ground level.
Burn 1lb of fuel, create 10lb of water , can't avoid it.

On the induction side the accepted ratio was a minimum of 8 tonnes of air per tonne of fuel. So at a burn of 50 tonnes per day that was a mass of 400 tonnes of air per day through the turbo's. It will be way in excess of that these days with higher efficiency engines striving for a cleaner burn but John is right about the water vapour; I also get that on starting and my emissions are bang on. If in doubt, get an emissions test. Might also be worth a dose of injector cleaner. It did wonders for the FM which had been neglected and run on supermarket fuel for too long.

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