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rfmaster · 12-11-2008, 06:37 PM

My apologies - 7747 does not have DFCO - MPH threshold, which is used in 8746 ECM found in TBI passenger cars. Also, DE is mapped to MAP and RPM threshold in 8746.

Now that I looked back at my notes I know where I got confused - in my conversion I used 16136965 from 1991 B-Body which just happens to be almost pin compatible with 1227747 (there are couple more control outputs and MAT input) which in its stock form uses speed threshold for DFCO. In the end it did not matter to me at all since I have converted to EBL which provides full control over DE and DFCO.

VSS in 7747 is used primarily for TCC control, Knock retard, Highway SA, EGR, & Idle speed compensation.

//RF

12-11-2008, 06:37 PM	#33
rfmaster Registered User Join Date: Oct 2003 Location: OC CA Posts: 1,374	Re: Tbi swap build thread My apologies - 7747 does not have DFCO - MPH threshold, which is used in 8746 ECM found in TBI passenger cars. Also, DE is mapped to MAP and RPM threshold in 8746. Now that I looked back at my notes I know where I got confused - in my conversion I used 16136965 from 1991 B-Body which just happens to be almost pin compatible with 1227747 (there are couple more control outputs and MAT input) which in its stock form uses speed threshold for DFCO. In the end it did not matter to me at all since I have converted to EBL which provides full control over DE and DFCO. VSS in 7747 is used primarily for TCC control, Knock retard, Highway SA, EGR, & Idle speed compensation. //RF __________________ "The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)