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RE: We're working many different things.
By Gerry Proctor - 06/03/2004 2:25:40 PM; IP 207.133.188.254
You're trying to blend carburetion and mechanical distributors to fully-electronic controls.

You're right, late ignition timing will make an engine run hotter since the burn is occuring out the port and rather than contributing to the thermal efficiency of the engine, it is going into heating up the coolant. But that's different from creating heat in the combustion chamber that is caused by high cylinder pressure.

I'm still wondering why you have so much advance in the system but I suppose you're working from a manufacturer's recommendation. Usually, you will see high teens to low 20s on the advance for a cold engine. And low to mid teens once in closed loop. Some engines are tuned for a bit more, some a bit less. It's more of an emissions issue. Yep, mechanical distributors did use a thermal vacuum switch, depending on the emissions set up. Some even delayed spark advance while cold until the transmission was in high gear.

Sorry, I have no single source link I can send you to. There are OBDII forums that may be able to address your issues more thoroughly than I have or can.
This thread, so far...
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Collapse <a href=../ForumFE/reply.aspx?ID=21694&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21694" onclick="return false;">More questions on timing...not answered below</a>&nbsp;-- <font color=#0000ff>Walker, <i>06/02/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21694', contentMargin: 60, icon: $('anchor21694') }); </script>  More questions on timing...not answered below -- Walker, 06/02/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21698&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21698" onclick="return false;">RE: More questions on timing...not answered below</a>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>06/03/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21698', contentMargin: 60, icon: $('anchor21698') }); </script>  RE: More questions on timing...not answered below -- Gerry Proctor, 06/03/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21700&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21700" onclick="return false;">Why: it's DIS, so 'vacuum advance' is now MAP adv</a>&nbsp;-- <font color=#0000ff>Walker, <i>06/03/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21700', contentMargin: 60, icon: $('anchor21700') }); </script>  Why: it's DIS, so 'vacuum advance' is now MAP adv -- Walker, 06/03/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21701&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21701" onclick="return false;">RE: Why: it's DIS, so 'vacuum advance' is now MAP adv</a>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>06/03/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21701', contentMargin: 60, icon: $('anchor21701') }); </script>  RE: Why: it's DIS, so 'vacuum advance' is now MAP adv -- Gerry Proctor, 06/03/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21702&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21702" onclick="return false;">But at STARTUP? need some explanation/theory</a>&nbsp;-- <font color=#0000ff>Walker, <i>06/03/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21702', contentMargin: 60, icon: $('anchor21702') }); </script>  But at STARTUP? need some explanation/theory -- Walker, 06/03/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21703&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21703" onclick="return false;">RE: Now it gets complicated.</a>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>06/03/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21703', contentMargin: 60, icon: $('anchor21703') }); </script>  RE: Now it gets complicated. -- Gerry Proctor, 06/03/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21704&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21704" onclick="return false;">I thought RETARDING the timing raised temp's</a>&nbsp;-- <font color=#0000ff>Walker, <i>06/03/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21704', contentMargin: 60, icon: $('anchor21704') }); </script>  I thought RETARDING the timing raised temp's -- Walker, 06/03/2004
Collapse <b>RE: We're working many different things.</b>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>06/03/2004</i></font>RE: We're working many different things. -- Gerry Proctor, 06/03/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21706&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21706" onclick="return false;">Still looking for theory on advance timing.</a>&nbsp;-- <font color=#0000ff>Walker, <i>06/03/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21706', contentMargin: 60, icon: $('anchor21706') }); </script>  Still looking for theory on advance timing. -- Walker, 06/03/2004
Collapse <a href=../ForumFE/reply.aspx?ID=21712&Reply=21694><img src=../images/reply.png width=30 height=10></a>&nbsp;<a href="#" id="anchor21712" onclick="return false;">RE: Still looking for theory on advance timing.</a>&nbsp;-- <font color=#0000ff>Gerry Proctor, <i>06/04/2004</i></font><script type="text/javascript"> new HelpBalloon({ dataURL: 'replyb.aspx?ID=21712', contentMargin: 60, icon: $('anchor21712') }); </script>  RE: Still looking for theory on advance timing. -- Gerry Proctor, 06/04/2004
 I was surprising myself every new cold day... -- Walker, 06/04/2004
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