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I am looking high and lo for information on rebuilding my 4 liter YJ engine. Primarily looking at performance engine mods, strokers from 4.2 to 4.7, cams, heads, and so forth. One of the things I have been told is as I increase cam, and air throughput, the engine will run lean. Some have said to go with a JET chip, others have said change computer(?) and F/I's. A friend (?) said there is a way to use a resistor across some lead on the pin-out for the computer to trick it into running advance and force the computer to enrich the mixture. This sounds like a dangerous technique, and is something I have not heard of. Anyone else hear of this technique? Thanks!
NEO
 

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It's something that I heard about in the import tuning world...they usually do it to the MAF. The resistor fools the computer into thinking that you are sucking in much colder air. So the ECM advances timing and richens the mix a bit.
 

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Thanks guys for the responeses! Is this worth doing, or is this half-assed? How does one figure out where to place the leads, and how much resistance is needed?
 

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Just build yourself an adjustable MAP sensor, not hard to do at all and CHEAP. Plus you can fine tune that a lot easier than a resistor.
 

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AthlonAJ said:
Just build yourself an adjustable MAP sensor, not hard to do at all and CHEAP. Plus you can fine tune that a lot easier than a resistor.
So have you done it and do you have any information about the performance of this mod? Does anyone have good or bad stories about this adjustable MAP sensor?

I read this a year ago, before the MPI conversion and thought this would help a lean motor(which I seem to have).
 

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MADXJ.com has a write up on the custom mapsensor

oorrr you could take the easy way out and relocate your IAT sensor and get some new injectors...youll be rich enough

PS: dec 00 register date and 15 posts, that has to be some kind of record :flipoff2:
 

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The adjustable MAP doesn't really benefit you unless you were running a stroker motor and needing to fine tune your fuel delivery. Relocating the IAT is a small gain though, just moving it off the intake manifold to the air tube lowers the reading a bit.
 
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