jules Posted June 13, 2009 Share Posted June 13, 2009 Will a 4.6 run happliy with a 3.9 or 4.2 plenum EFI system on it. I'm assuming it should be fine although I will note get the max out of the 4.6 which could be a good thing Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted June 13, 2009 Share Posted June 13, 2009 Being really picky it may run a tad weak on 3.9/4.2 ecu and the fuel maps within, esp if booted about - not that of course applies to your sensible driving stylee You can if you really wnat get a EPROM and have the fuelling reset, or there is of course Mwegasquirt (Now you didn't think it wouldn't get a mention did you ? ) HTH Nige Quote Link to comment Share on other sites More sharing options...
jules Posted June 13, 2009 Author Share Posted June 13, 2009 I know a man that can deal with the remapping for me but I like the simple fit and forget that comes from fitting factory stuff if I fitted MS I would have the temptation to continuously tinker which is not a good think if I'm the tinkerer My plan would be have the 4.2 remapped and utilise the AUS mapping benefits as well EG no speed restriction and no lumber sensors Quote Link to comment Share on other sites More sharing options...
Dave W Posted June 13, 2009 Share Posted June 13, 2009 Providing you use the complete setup from the donor engine there is no reason I can see for it to need remapping. The AFM will compensate for the extra air going in and increase the fuelling accordingly. That's one of the benefits of an AFM, it gives the ECU precise (ish) measurement of the air mass going into the engine. Obviously a remap wouldn't do any harm but it shouldn't be necessary for, effectively, an engine capacity change. Quote Link to comment Share on other sites More sharing options...
landybehr Posted June 13, 2009 Share Posted June 13, 2009 Providing you use the complete setup from the donor engine there is no reason I can see for it to need remapping. The AFM will compensate for the extra air going in and increase the fuelling accordingly. That's one of the benefits of an AFM, it gives the ECU precise (ish) measurement of the air mass going into the engine AFAIK the ECU´s for 3.9 and 4.2 are the same (resp. have the same part number on ´94 catalogue IIRC). Which proves right what Dave just wrote. I cannot tell though, if the additional displacement for the 4.6 might ask too much from the ECU to compensate. If the compensation exceeded a certain range the programmers of the ECU might just as well have had assumed anything would be broken then (f.i. lambda sond) and not allowed the ECU to go further away from default. ??? Quote Link to comment Share on other sites More sharing options...
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