Jump to content
CaddyInfo Cadillac Forum

2002 STS with P0300 hopefully solved


Recommended Posts

As I mentioned in another thread "Finally time fo another car", my STS suddenly developed a miss. I just returned from the garage and won't have to search no further...

As you can see the spark plug has a broken electrode and the center terminal had separated from the spark plug. I've decided to replace them all and also buy a torque wrench more accurate than the one I used since the spark plug also was loose. Hopefully the problems stems from the plug and not from something else. I.e. I'm only curing the symptoms.

There were a lot of residues inside the spark plug well. At the bottom nearest the combustion chamber mostly black soot as expected with a loose plug. Higher up, closer to the ignition control module, there were mostly a grey residue. I discovered that it was magnetic and hopefully it comes from the plug itself when it was disintegrating, if not I have problems…. I’ll order new plugs and will get my hands on a torque wrench that better fits my needs. I don’t want the plugs to come loose and I surely don’t want to ruin the aluminum threads. It seems like my preventative measure to use a torque wrench for the plugs did bite me in the behind.

 

 

IMG_3907[11067].JPG

Link to comment
Share on other sites


Ah, the old disappearing plug trick.

If you are selling the car soon, single Platinum OEM-style plugs are good (my experience is 60,000 miles/1000 km for peak performance).  If you plan to keep the car or sell/give it to a relative or close friend, double platinum plugs should go over 100,000 miles/165,000 km.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

Link to comment
Share on other sites

I’m just worried about all that fine powder residue I discovered. Black soot would be alright with me but grey metallic dust? I'm probably worrying for nothing. I guess it comes from the defect plug since the grey dust only was present at the top of the spark plug recess. On the bottom there were black soot as expected since the plug was loose.

To be sure I'll give my wife the car ;)

Link to comment
Share on other sites

Wife's car.  That calls for eight double platinum plugs and a thorough cleaning of all ignition-related, injection-related, and PCM-related, wiring.

Deposits of any kind can be present in plug wells.  The high potential electric fields in the plug boot and insulator collects dust of whatever kind is in the air, and that's underhood air.  I wouldn't think a thing of it unless there are profound differences in one plug well or something that focuses on one cylinder or tracks back to the ignition module.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

Link to comment
Share on other sites

16 hours ago, Cadillac Jim said:

Wife's car.  That calls for eight double platinum plugs and a thorough cleaning of all ignition-related, injection-related, and PCM-related, wiring.

Deposits of any kind can be present in plug wells.  The high potential electric fields in the plug boot and insulator collects dust of whatever kind is in the air, and that's underhood air.  I wouldn't think a thing of it unless there are profound differences in one plug well or something that focuses on one cylinder or tracks back to the ignition module.

That just why I'm worried. All that dust is in just one spark plug well, the one with the defect plug. The other ones are clean. I would think that the rubber boots that provides connection between plugs and the ignition module keep dust away from the outside on this vintage. So my conclusion is that the residue comes from the exhaust gases leaking through the loose plug. Well I'll change the plugs and keep my fingers crossed!

Link to comment
Share on other sites

It is less expensive and faster to order them from Rock-Auto than to buy them in Sweden and hopefully I'll get them on Thursday. In the mean while I’ll drive a rental car. My insurance company gracefully let me have one for seven days to a cost of only ¼ of what It normally would cost. A car like this, an Opel Corsa, costs about $70…a day! 0-60 in forever and 4000 rpms at 60 mph, truly an ugly, noisy and overall repulsive automobile:

90bhp
5 speed manual
0-60 in 13 secs
genuine plastic interior
cloth seats
darn near impossible to adjust to a comfortable sitting position
funny looking
ridiculous driving behavior

A colleague of mine said "What was that thing you were driving? Aren't you ashamed?" "Well yes, that is why I was driving it so fast! Otherwise someone might have seen me"

I had one two days the last week. On day two the car started to act funny, I guess that me trying to make it perform at "peak level" if you can call 0-60 in 13 secs for a peak took its toll on it :ninja:

 

opel-corsa-5-door-side-dubai-motor-show-2015-0-185681.jpg

Link to comment
Share on other sites

Perhaps the appeal is enhanced by the two sport bicycles mounted on the rear hatch.  The minicar *is* easy to park.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

Link to comment
Share on other sites

Yes! Hopefully no need for a rental car for a while now. The STS runs smooth, strong and silent as it is supposed to do again. There is only so much one can do to keep a car running. Regular service and the use of eyes, ears and the nose can go far in order to evaluate the car health besides the OBD system but electronics can go out without a warning. The STS has had a ticking sound for a while now which I was certain was just a tired valve lifter. But now it seems that is was probably arching that I was hearing because the car is purring just like a steam engine J

 

Link to comment
Share on other sites

It's also possible that the black deposits in that plug well were a result of leakage of the internal seals of that plug.  The plug failed because the center insulated electrode assembly corroded, and I suspect that failure of the seals started the process.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

Link to comment
Share on other sites

It was scary. In any car with about 190k miles and 15 years on them one thinks "so this is perhaps it" when the car starts to act up and you see strange things. I have always driven the car as it is supposed to run. Hard but not abusive and 6500 rpm shifts at WOT at a daily basis. I think that if and when it breaks, I'll either fix it or garage it until I have the time and place to fix it. The V will have a ridiculous amount of power so in that perspective I’ll perhaps only use half throttle when I’m used to WOTs

Link to comment
Share on other sites

The 6.2 liter supercharged V engine does not accumulate carbon like the Northstar.  With no boost, it is just a low-compression big V8 with a conservative cam that happens to have ultra-high lift.  With boost, it's a VVT monster tuned to have huge torque that does not vary much over the RPM band.  It doesn't need WOT to keep clean and ready-to-go.

This engine, at 6.2 liters and 556 hp, is rated at only 90 hp/liter.  Compare this to the Olds Quad 4 HO, the hottest of which was rated at 195 hp, which at 2.26 liters is 86 hp/liter, and this normally-aspirated four-cylinder DOHC was sold in the little Olds 4-4-2 revival compacts of the 1990's.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...