gju614

I just picked up a j&s, mostly due to sharkcohen's advise and others on the board who seem very satisfied and feel safer using one. Which would be the best way or recommended way to use this setup? Obviously the pms will handle my fuel needs, but what about timing and map limiter? All three can deal with my timing and both the jrsc or j&s can limit the map signal. Should I even bother with the jrsc electronics and let the j&s handle timing and map limiter? Or just use the j&s as a monitor with the jrsc electronics? Or pms for fuel and timing with the j&s for map limiting and timing monitor? Since all of them can control my timing, there are quite a few options.

Thanks again!

 

sharkcohen

If you plan on using the J&S + the PMS, then you will be ditching the JR electronics entirely. If you purchased the J&S V2 which has a map limiter, you will be using that map limiter. The PMS will be used to control your ignition and fuel curves. You will also be using the boost tables in the PMS for the ignition and fuel curves, so there will be no need to use the boost timing retard function of the J&S (turn the "start" knob all the way up, and the "rate" knob all the way down).

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schwett

ditch the jr electronics.

run the map signal from the map sensor to the j&s limiter circuit to the pms harness. the pms will pass the limited signal on to the stock ecu unmolested. run a gm 3 bar map sensor from any boost sensing vacuum line (the one formerly connected to the jr ems inside the cabin is convenient) and connect the map sensor to the "optional" map sensor input on the pms.

use the pms for fuel timing, retarding/adding fuel per psi, but also tuning the 'base' fuel & timing map per rpm and throttle position. you may find that you need to pull less timing "up top."

don't set any boost dependent timing retard on the j&s, but you do want it to do it's normal job of retarding timing on a cylinder by cylinder basis when it senses detonation. that's the part which will save your motor.

[edit] yeah, what sharkcohen said..... had the reply box open while he replied with the same thing i was about to say.

gju614

Thanks guys... I figured one of you guys would be able to clear this up for me.

gju614

Sorry, but can you run this by me again... I'll have 2 map sensors hooked up?
1). The factory one connecting to the j&s and then to the pms harness ( which wire? ).
2). The 3 bar sensor connecting to the "optional" map sensor input on the pms.

Am I getting this right or do I need to get some more sleep?

sharkcohen

When you wire up the J&S, you will be cutting the MAP wire and wiring in the J&S between the two halves. As for this wire then passing through the PMS harness, schwett was helping you visualize the path that the wire will take when you plug the PMS harness in between the ecu wire harness and the ecu. You will then adjust the MAP limiter knob on the J&S so that it prevents the ecu from receiving a boost signal from the stock MAP sensor. The 3 bar sensor will allow the PMS unit to sense boost.

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gju614

Thanks sharkcohen... I think I got it now. The j&s doesn't hooked up to the pms harness at all. The j&s will connect to the factory sensor signal coming into the ecu, preventing any error codes. The pms will actually be reading signals from it's own sensor. Right?

Thanks

sharkcohen

That is correct

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gju614

Thanks shark!