I've noticed that MAF cars generally have a MAP sensor, including my dad's GN. What function does this serve to the ECM? Is is to sense vacuum for the EGR? When I look at the wire diagram, I do not see it. However, I see an "EGR VACUUM SENSOR" pin "C15". Is that the MAP sensor? This would be on a "165" ECM.

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82' Z-28. 327" w/ flat tops. 216/228/112LS. Pocket ported 041 heads 1.94/1.50 SS valves. World Class T-5 from a 91'. Best run? Runs with 2001 vette to 150mph! Soon to be converted over to TPI w/ supercharger.

 

The GNs and TTAs use the sensor for the indicator lights for boost on the dash, they are not tied into the ecm.

The EGR vas switch is just a pressure switch to make sure there is vac present at the egr controller.

On some PCMS (like the LT1 and LS1s) they use both, the MAP is kinda a double check on tht MAF, and maybe used for sudden transistions, and the MAF for more steady state.