Black sparkplugs - Miata Turbo Forum - Boost cars, acquire cats.

General Miata Chat A place to talk about anything Miata

Black sparkplugs

Old 11-06-2018, 02:55 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Jun 2014
Location: Norway
Posts: 51
Total Cats: 0
Default Black sparkplugs

My setup: 1990 1.6 NA. With M45, intercooler, MSPNP, 550cc injectors, bigger fuel pump etc.
I know I'm running crazy rich. The plugs are very black and some of the have oil on the threads.






helly is offline  
Old 11-06-2018, 03:03 PM
  #2  
Junior Member
 
Join Date: May 2017
Posts: 393
Total Cats: -36
Default

Calling Pat the Spark Plug reading genius.

To me it looks like a combination of silly rich and burning oil. Does your car tend to use oil at a accelerated rate?
andyfloyd is online now  
Old 11-06-2018, 03:44 PM
  #3  
Senior Member
 
matrussell122's Avatar
 
Join Date: Sep 2016
Location: Seattle
Posts: 908
Total Cats: 99
Default

You are exactly right those plugs are way too rich and its burning oil (more so not burning)
matrussell122 is online now  
Old 11-06-2018, 03:48 PM
  #4  
SadFab CEO
iTrader: (3)
 
hi_im_sean's Avatar
 
Join Date: Sep 2012
Location: your mom's house phoenix, AZ
Posts: 4,425
Total Cats: 983
Default

You don't need to be a plug reading genius to know its burning oil, lots of oil. And how can you guys even comment on AFRs when the plug are fuking dripping in oil?

Valve seals, PCV, rings....
hi_im_sean is offline  
Old 11-06-2018, 05:30 PM
  #5  
Junior Member
Thread Starter
 
Join Date: Jun 2014
Location: Norway
Posts: 51
Total Cats: 0
Default

PVC is new. The car does not use that much oil. And I know the CAS o-ring is leaking. Compression was good the last time I checked. Car works fine.
Valve seals then?
helly is offline  
Old 11-06-2018, 05:45 PM
  #6  
Elite Member
iTrader: (21)
 
Join Date: Jun 2007
Location: Rochester, NY
Posts: 6,000
Total Cats: 768
Default

Threads are wet. That indicates oil in the plug wells. That indicates a poorly sealing head gasket around said plug wells. Tighten head cover to proper specs in proper order. See if it helps.

And do something about that extra gas. You are running pig rich.
rleete is offline  
Old 11-06-2018, 07:11 PM
  #7  
Senior Member
 
Join Date: May 2007
Location: Atlanta
Posts: 509
Total Cats: 66
Default

Valve cover, not head.
gooflophaze is offline  
Old 11-06-2018, 07:15 PM
  #8  
Elite Member
iTrader: (5)
 
Join Date: Oct 2007
Location: Canton, Ga
Posts: 1,944
Total Cats: 39
Default

Replace valve cover gasket, clean the holes, try again
Stealth97 is offline  
Old 11-06-2018, 09:11 PM
  #9  
Elite Member
iTrader: (21)
 
Join Date: Jun 2007
Location: Rochester, NY
Posts: 6,000
Total Cats: 768
Default

Originally Posted by gooflophaze View Post
Valve cover, not head.
Yes, you are correct. My bad.
rleete is offline  
Old 11-07-2018, 05:27 AM
  #10  
Junior Member
Thread Starter
 
Join Date: Jun 2014
Location: Norway
Posts: 51
Total Cats: 0
Default

EDIT: If the valve cover seal is leaking. Shouldn't the top part of the spark plugs be covered in oil then? At least some?

Thanks for the help.

Valve cover got replaced along with cam-gasket, waterpump, belt etc. But that about.. .wow.. Time flies! 5 years ago maybe. I did tighten the valve cover according to this book.
Amazon Amazon
and I did use the correct torque.
I've got a spare gasket, so I'll swap it asap and update this thread, so that people with the same problem can find this thread in the future :-)

BTW: Isn't it easier to change the CAS O-ring when the valve cover is off ?

Last edited by helly; 11-07-2018 at 05:41 AM.
helly is offline  
Old 11-07-2018, 10:14 AM
  #11  
Elite Member
iTrader: (5)
 
Join Date: Oct 2007
Location: Canton, Ga
Posts: 1,944
Total Cats: 39
Default

Originally Posted by helly View Post
BTW: Isn't it easier to change the CAS O-ring when the valve cover is off ?
Way easier, so you can see the dogs on the CAS engage the cam
Stealth97 is offline  
Old 11-07-2018, 12:36 PM
  #12  
Senior Member
 
Join Date: Oct 2013
Location: NorthWest NJ
Posts: 1,297
Total Cats: 63
Default

The top part of the spark plug is mostly covered by the wire boot. They tend to stay clean. That's least of your worries though. Also, you need to retorque the valve cover bolts after a few drive cycles I have found.

But yeah, you are either running pig rich everywhere or burring a good bit of oil.
x_25 is online now  
Old 11-07-2018, 12:49 PM
  #13  
Junior Member
Thread Starter
 
Join Date: Jun 2014
Location: Norway
Posts: 51
Total Cats: 0
Default

I think it's a combination.
No tuner near me. So I've just autotuned it a bit rich.. I know it's too rich on WOT.
The car is now stock again. Need it to pass inspection.

I hope 18psi is ready to tune when the summer comes around :-)
helly is offline  
Old 11-07-2018, 06:02 PM
  #14  
Junior Member
 
Join Date: May 2017
Posts: 393
Total Cats: -36
Default

Originally Posted by helly View Post
I think it's a combination.
No tuner near me. So I've just autotuned it a bit rich.. I know it's too rich on WOT.
The car is now stock again. Need it to pass inspection.

I hope 18psi is ready to tune when the summer comes around :-)
I would say thats more than a bit rich, in order for the plugs to look that bad it has to be running pig rich under all conditions not just WOT.
andyfloyd is online now  
Old 11-08-2018, 06:02 AM
  #15  
Junior Member
Thread Starter
 
Join Date: Jun 2014
Location: Norway
Posts: 51
Total Cats: 0
Default

I was being ironic.

Se my first post:
I know I'm running crazy rich.
helly is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
danscreations
Miata parts for sale/trade
12
05-11-2009 01:29 PM
blaise
Supercharger Discussion
3
04-10-2009 10:20 AM
Swags04
Cars for sale/trade
5
11-28-2008 12:06 AM
Swags04
Cars for sale/trade
7
09-08-2008 03:30 PM
Swags04
Cars for sale/trade
2
05-28-2008 05:28 PM


Quick Reply: Black sparkplugs


Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.