electronic spark timing

[mjol]

Can any one tell me the location of the EST relay on my '99 Tahoe [ x cop car if that matters ] so I can disconnect it to check my timing? My Haynes manual shows it on the passenger side of the firewall but is not there... This vehicle was the subject of an earlier question with the title of " just quit ", since the post I replaced the fuel pump and fuel lines, lines were kinked and I was concerned of low voltage not driving the pump at idle, also checked the iac valve and found it to be ok... I had replaced the intake gaskets a while back and had an issue with timing that showed the same symptoms... No other issues and other than stalling at idle the beast runs great ... 90+ k miles, no timing chain slack [3/16 ' ]...
Thanks in advance, GREAT forum............ Mike

 

[SunlitComet]

you have no such relay or connection. your timing is completely controlled my the pcm. your only goal when putting the dizzy is to make sure the cam/crank correlation is set to 0%.