Smoke on start and wet spark plug

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Hello everyone, new here so hope you can help.

I have a Seat Leon Cupra R MK1.

I noticed that the car has been back firing now and again. It tends to do it between gear changes when cold and warm. Say once or twice every 10 minutes.

I've also started getting a lot of smoke on start up, that appears to stop when the engine has warmed up. I've checked for fault codes using VAG-COM and no faults are found.

I checked the spark plugs and found:
Cylinder 1 - Red/Tan coloured - I used octane booster recently, so likely to be this by the look of it?
Cylinder 2 - Wet and sooty.
Cylinder 3 & 4 - Unsure. Started to rain and they're awkward to get to.

Maybe related, but the PCV valve has been plugged up by a previous owner.

Any ideas?
 
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Hi,
So I started the car when cold this morning and it's definitely BLUE smoke (so oil). If I rev the engine when stationary, the revs drops and the smoke gets much worse.

I've bought a compression tester which should arrive tomorrow. Does anyone know what the figures should be?

Thanks,
 
A good move on the compression tester......look for over 200 psi just as an average, and all cylinders should be the same or very nearly so.
Its nothing to do with your problem, but those plugs are well worn!
John :)
 
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Pressurising the crankcase courtesy of a bypassed PCV has got to make this problem worse, methinks!
John :)
 
A good move on the compression tester......look for over 200 psi just as an average, and all cylinders should be the same or very nearly so.
Its nothing to do with your problem, but those plugs are well worn!
John :)
Will do. Just watched a YouTube vid on doing wet & dry tests so will do that tomorrow.

It's strange you mention the plugs are worn, as apparently they were changed 8k miles ago..

Not sure why you would plug the pcv valve, trying to disguise something maybe?
Perhaps... but if so, what/why?

Pressurising the crankcase courtesy of a bypassed PCV has got to make this problem worse, methinks!
John :)
Yeah, I did hear this can increase blow by.. I'm not sure why it was bypassed though.

Thanks for the replies :)
 
The centre electrode on the clean plug looks well worn to me - unless its the photo or my eyesight!
John :)
 
Maybe they thought bypassing it was some kind of performance gain being turbocharged
Perhaps. I know that the PCV valves on these cars are crap! perhaps it was an alternative to replacing it?
 
Hi Guys,
Did the compression test today. Results are:
[code:1]
1 2 3 4
Dry 170 135 168 173
Wet 178 155 182 192
[/code:1]
Piston rings??
 
Those figures are all low.....I'd be hoping for around 240 psi on an engine like this.
Obviously cylinder 2 speaks for itself.
Its just indicative of a worn engine, I'm afraid.....you may find the valve seats are past their best too, if you decide to take the engine down.
Piston rings alone are rarely a cure - the cylinder block would ideally need reboring - if thats possible.
John :)
 
As already said, vent the sump to the outside, never block.

Oil change might help if its in a while?

Watch the wet cylinders see if they dry out, when you vent the sump to the outside air. Move the wet plugs around see it the problem moves with the plug, but it looks like unburnt oil on the wet plugs to me. Probably causes by no vent on the sump.
 
How many miles are on it?

Put the pcv back to standard (£10 from a scrap yard), set of new plugs (£14 odd) and see what its like after that?



Daniel
 
Those figures are all low.....I'd be hoping for around 240 psi on an engine like this.
Obviously cylinder 2 speaks for itself.
Its just indicative of a worn engine, I'm afraid.....you may find the valve seats are past their best too, if you decide to take the engine down.
Piston rings alone are rarely a cure - the cylinder block would ideally need reboring - if thats possible.
John :)

Looking here they sound about right (apart from cylinder 2 obviously): http://forums.vwvortex.com/showthread.php?5457869-High-Mileage-Compression-Test



As already said, vent the sump to the outside, never block.

Oil change might help if its in a while?

Watch the wet cylinders see if they dry out, when you vent the sump to the outside air. Move the wet plugs around see it the problem moves with the plug, but it looks like unburnt oil on the wet plugs to me. Probably causes by no vent on the sump.

Oil & Filter was changed a few thousand miles ago. Will try that, thanks.

How many miles are on it?

Put the pcv back to standard (£10 from a scrap yard), set of new plugs (£14 odd) and see what its like after that?



Daniel
Around 60k so not many. Will look at hooking up the PCV system before doing a service.

Thanks again,
 
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