The install guide says to mount the MJLJ inside the car to avoid overheating/damage from vibration. how do i run a vacuum line into the cab?? i would think a vacuum line that long would cause problems with getting an accurate, even pressure reading?
also, if i plan on doing an EFI conversion soon, does it make sense for me to buy an MS-2 wiring harness to use for the MJLJ until i get a full megasquirt kit? i'm having a LOT of trouble trying to figure out how much of each size/color wire i need for the install.
Running vacuum line for MAP sensor??? AND a wiring question
Moderators: JeffC, rdoherty, stieg, brentp
Re: Running vacuum line for MAP sensor??? AND a wiring quest
hi...bflan2001 wrote:The install guide says to mount the MJLJ inside the car to avoid overheating/damage from vibration. how do i run a vacuum line into the cab?? i would think a vacuum line that long would cause problems with getting an accurate, even pressure reading?
also, if i plan on doing an EFI conversion soon, does it make sense for me to buy an MS-2 wiring harness to use for the MJLJ until i get a full megasquirt kit? i'm having a LOT of trouble trying to figure out how much of each size/color wire i need for the install.
*you can make the vacuum hose as long as needed; mine is about 2m long and has no trouble sensing the vacuum at that distance. seems the tiny intertia of air allows for this.
*if, however, you have individual (ie unconnected) intake runners, note the desirability of connecting vac pipes from each runner, in a small chamber, prior to running one vac pipe to the mj. that evens out the distinct pressure pulses which exist in individual intake manifolds. see the installation guide for ideas on that.
*not 100% sure, but i dont think the MS harness connects with the MJ, does it? there are several options with MS for spark control (roughly, i think, early versions with the addition of MS&E code, or later MS version), OR simply use MS for fuel and MJ for spark. they can both be driven independently from the same EDIS signal. there is not, to my knowledge, any connetion between the two products. brent?
*re wire - yes, it is actually a bit difficult to identify wire sizes as there are several ways of expressing it! i used 10amp or 15amp multistrand wire for the non power connections. any smaller, and it becomes difficult to work with, particularly in the crimp connections; any bigger and the wire is physically difficult to fit in the connector plug. i used 20amp wire for power wires and earth.
regards
alexander
well.... you can try ebay for universal wiring harnesses. i have seen a couple of suppliers in the US, and (more expensively, of course) in australia, where i am domiciled. i think, however, that for making a wiring harness for a MJ - and probably MS too - that you really only need some wire from an auto parts store. i think that red, black and, say 5 or 6 colours, is more than sufficient. and much cheaper than a universal wiring harness! that said, i was frustrated by the fact that i couldnt actually find anyone in australia who sold, say, auto wiring in a range of colours and coloured traces. perhaps i didnt look hard enough 
anyhow, just a few plain colours as noted, is enough, IMO. dont forget to draw a clear, neat diagram of what you have done, with the colours you used! then laminate it and put it in the car workshop manual. you, or some later owner, will thank you for it some time in the future!
cheers
alexander.
anyhow, just a few plain colours as noted, is enough, IMO. dont forget to draw a clear, neat diagram of what you have done, with the colours you used! then laminate it and put it in the car workshop manual. you, or some later owner, will thank you for it some time in the future!
cheers
alexander.