Hello all, UPDATE

I'm new just got this honda s2000 back in Late December 2019. Here are the details:

Miles : 150,000 the car never was run in track only highway and daily use before i got it and put all these parts:

Parts :
AEM V2 Cold Air Intake
Skunk2 70mm Alpha SeriesThrottle Body
OBX Headers
Invidia Test pipe 70mm and Invidia Q300 exhaust

Oem ECU

The problem started three months ago when i put the test pipe, the car started to blow some smoke, sometimes blue sometimes gray but not all the time, mostly when rolling down with no gas and other times while i was rolling at 15mph and never at the highway.

Due to this less than one month ago we did a Leak test and Compression test, also changed the valve seals and changed the oil. (using mobil1 10w30)

The results were:

Compression test: 210 psi all cylinders

Leak Test:

Cylinder 1: 2%
Cylinder 2: 8%
Cylinder 3: 2%
Cylinder 4: 4%

UPDATE!!

Since the smoke continued, we decided on October 2020 to rebuild the engine

We changed retainers, valve guides, rings, bearings and rectified the head as well.

However, the smoke is still there, any thoughts?

 

This is one of my favourite subjects A few things to consider, Firstly, it would be good to know if your smoke issue unburned fuel or is it burning oil, or a combination of the two ? White smoke, blue smoke, black sooty smoke ?

Unburned fuel and a test pipe can explain most of the smoke IMO. S2000's run really rich at the top end so unburned fuel can create smoke with a test pipe. If you run a proper oem type of cat. converter you wont see the smoke as it gets converted to other byproducts. My S2000 smoked with a test pipe, but stopped smoking as soon as I put the cat converter back on.

The 8 percent leakdown is a potential source for some smoke too, I would have expected that the new valve seals would have helped with that. That could be a source of oil seepage into the combustion chamber.

How old are the sparkplugs ? If the plugs are older and gaps are overly high, replacing them can help to reduce unburned fuel. If plugs are good then skip it.

Check your pcv system make sure it is working properly.

I run Liqui Moly motor oil saver on one of my Hondas which smokes at high rpm vtec after throttle closes. It contains esters to free up frozen piston oil rings over time, stuck in place with varnish and combustion deposits. I just started running it and it takes a few hundred miles before it might start showing benefits. I also run an upper cylinder lubricant in the fuel (Lucas or Redline Fuel Injector cleaner with upper cylinder lubricant), it keeps the valve stems lubed where they enter the intake ports. I figure it is worth a try for a relatively small investment even if it doesn't end up working. I hope to know more in a few weeks of running this regimen if it helps with my smoke issues.

 

The smoke you're seeing might just be carbon/soot from having a test pipe.

These cars burn a little oil...so maybe some of that too.

I wouldn't lose any sleep over it. Why is it a worry for you? Or are you just checking whether this is unusual?

I would just continue living my life if I were you.

 

Thank you so much for the response!

I did change the sparkplugs, put the ones that the s2000 use.

I have a cat deleted in the test pipe due to check engine.

Im willing to check the PCV system.

And will try that as well.

UPDATE : Being driving these days and no smoke.

 

Hey ! thanks for your response!

Yeah i think im kinda over reacted.

But will definetly check on PCV system and will think about refresh the motor.

 

My Ap1 started to smoke on occasion as soon as i put my test pipe on . I went back to a cat and the smoking stopped completely . I then put Krank Vents on and reinstalled the test pipe and what do you know ? The smoke stopped . The Krank Vents fixed the issue for me but they make a little clucky noise while the engine is idling . A small price to pay if you ask me .

 

Great info, I forgot about Krank vents, they do seem to be popular in addressing oil burning. I should look at them for my B18C motor. Thanks for posting. That integra race car sounds like great fun

 

Mobile1 has a reputation for high oil consumption in the S2000.

-- Chuck

 

I'm also having a similar issue after putting on a test pipe.

Most of the time it would happen right after stopping at a red light/stop sign and then getting the car moving. The car would blow a small/medium size smoke(grayish blue).

Changing the engine oil from Mobil 1 to Castrol made some difference. Another thing that made a difference is when I get off the gas pedal in mid-high rpm's, I don't let the engine run on vacuum, I put the car into neutral and let the car coast. I also swapped the valve cover/pcv to a 2004-05 system and that made no difference.

 

I'd rather blow massive smoke rather than not downshift.

Downshifting is fun asf to me.