EVO32

I bought a 94 gt convert over a month ago and realized that it was pinging when I had regular and the medium octane in it. I now have put in premium in and it does not ping at all. I also noticed that when I did a compression test on cylinders 5-8 "the easy to get to side" that the spark plugs show the signs of running lean. (Also I had a compression of 150 to 140 on those cylinders thats normal right?) I asked my dad and brother ( bro used to own a 91 gt) and they said that the timing could be advanced but when we tested the timing we noticed that it only moved forward something like a 1/4-1/2inch. Any thing that you guys know or want to suggest would be helpful.
Thanks, Ben

EVO32

Any one with suggestions? Im going to read the codes from my car if there is any on Friday when I get the reader in the mail. Just ordered it like two hours ago.

Stangsational

whats going on .. dont really know ur status as of now but the compression seems normal, check in relation to the other cylinders so u have a good idea of what is normal. 140-150 sounds about right. I would recommend a leak down test. What kind of ping are we talkin about exactly? predetonation? or a miss?sounds like an advanced condition. check for little metalic deposits aroudn the insulator tip. that should be a good indicator of a lean condition. In a rich condition the fuel acts as a cooling agent. The small metal particles are a result of excessive combustion temperatures. (due to a lack of fuel). Im a little tipsy right now because i just returned from a bbq... butanything to help. It wouldnt hurt to check the pulse width of the injectors, and pressure at the rail.

EVO32

Its a predetonation ping, Not a miss fire. when i took the plugs out i noticed that they are white looking which mean that either its over advanced, or running lean, and then there are other possiablities but im just not to sure. im going to put new plugs in once i get around to it this weekend cause they look like that they are the original ones back from 94 when it was produced.