Guest Anonymous Posted December 29, 2005 Report Share Posted December 29, 2005 L27 = 3.8L Gen I That's what I get, but is there a difference between MFI (which is what the RPO says) and TPI (which is on my engine cover). Then the Engine Page on the w body front page uses Sequential, which is something else. Huh? Quote Link to comment Share on other sites More sharing options...
99RegalGS Posted December 29, 2005 Report Share Posted December 29, 2005 TPI = Tuner Port Injection. Which is the Intake design of the engine. MPI = Multi-port-injection. Which means there is one fuel injector per cylinder. SFI = Sequential Fuel Injection. Which means the fuel injectors fire in sequence with the engine's firing order. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted December 29, 2005 Report Share Posted December 29, 2005 I think I know the difference between MPFI ( multi port fuel injection) and SFI (seqential fuel injection). On MPFI, ALL the injectors fire at the same time, and the fuel sits on the closed intake valve for a split second until it opens. On SFI, the injectors fire independently from each other, only when it's intake valve is open. Correct me if I'm wrong.... Quote Link to comment Share on other sites More sharing options...
manitcor Posted December 29, 2005 Report Share Posted December 29, 2005 I think I know the difference between MPFI ( multi port fuel injection) and SFI (seqential fuel injection). On MPFI, ALL the injectors fire at the same time, and the fuel sits on the closed intake valve for a split second until it opens. On SFI, the injectors fire independently from each other, only when it's intake valve is open. Correct me if I'm wrong.... Thats right, also all SFI engines are MPFI. SFI is fuel econ technology. At WOT, when theengine is cold, there is a bad cam signal or in limp home mode the pcm defaults to MPFI. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted December 29, 2005 Report Share Posted December 29, 2005 On MPFI, ALL the injectors fire at the same time i thought they were fired 3 at a time (batch fired)? IOW each injector on the front side gets fired and then the other bank of injectors gets fired? Quote Link to comment Share on other sites More sharing options...
Crazy K Posted December 29, 2005 Report Share Posted December 29, 2005 On MPFI, ALL the injectors fire at the same time i thought they were fired 3 at a time (batch fired)? IOW each injector on the front side gets fired and then the other bank of injectors gets fired? my harness analysis confirms that they are wired as two parallel sets of three, reflecting your thought. I assume you are correct. p.s. on 3.1 and 2.8 engines I have worked on And the SFI each share a single (split 6 way) hot wire, and have seperate (ie 6) grounding wires (3100) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 30, 2005 Report Share Posted December 30, 2005 That explains it. I was wondering if someone had gotten mixed up or what. Thanks! Quote Link to comment Share on other sites More sharing options...
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