jdoyle

iTrader: (27)

Plugs are stock AC Delco's for an '04 Z06.
They have been in my '99 Z28 for 20K miles.
My Camaro is N/A only, never been sprayed.

I am not exactly sure what else you might need to know, but if I am missing something, let me know and I will post it up.

From what I can tell right now, the plugs look like they are saying that the idle tune is too rich or fat.

I apologize in advance for the crappy pictures.

Thanks.

crainholio

iTrader: (2)

White crystalline deposits are usually coolant contamination, that pic w/ 3 plugs all 3 appear to have them.

Time for a cooling system pressure test (free tester via AutoZone loan-a-tool). The cooling system test is very quick 'n easy, just click the test fixture onto your radiator in place of the cap and pump it up to whatever your cap pressure is...usually 16psi. It should hold that pressure for several minutes with zero drop.

If it passes that test, it's time for a cylinder by cylinder leakdown test.

The pic on the far left looks like a very rich fuel mixture.

MjMaro

iTrader: (11)

Info which should prove helpful:

http://www.ngksparkplugs.com/tech_su...qs/faqread.asp

LS14EVR

iTrader: (3)

I thought plug reading was a thing of the past due to all the detergents in gas etc. etc. etc.

crainholio

iTrader: (2)

It's probably not as useful a tool as it was back before closed-loop computerized fuel management, but many engine problems still show up in the combustion chamber. Plugs are easier to remove than heads.

LS14EVR

iTrader: (3)

True, easy to find major problems, hard to tune an engine. I've only dealt with 2 strokes. And getting a plug reading on a 2 stroke is next to impossible. Better to use piston wash. But I know, this is 4, but still thought it was next to impossible.
Anyway. Just throwing it out there and trying to learn at the same time.

crainholio

iTrader: (2)

Same here, I was an OMC Master Tech way back when and aside from diagnosing gummed carbs and overmixed fuel:oil the plugs weren't much use.

The white specs on the three plugs the guy posted are a likely indicator that things aren't right.

jdoyle

iTrader: (27)

what if it fails that test?

jdoyle

iTrader: (27)

thanks man, definitely helpful.

crainholio

iTrader: (2)

If you have to ask, then it's probably time to take it to a garage.

jdoyle

iTrader: (27)

what i meant was, are there any common leaking spots in the cooling system on these cars?