how does the isc work?

[speedfreak]

i think i understand the isc in a very general way which is, the isc uses the coolant temperature to determine extra air added or taken away for idling. can someone shed some light on this for me, i am going to be tuning with stand alone soon and am wondering if this will ruin my fuel values for warm up. thanks all

 

[mkIIIman089]

Since the throttle plate is completely shut when you release it, the ISC controls all the air for idling all the time. The most important variation it does is raise idle for cold engine running, but it also has more minor variations for things like electrical load, etc. BTW, all of this is controlled by the TCCS, the ISC has no computing power of its own.

As for ruining your fuel values, I can't comment really as I'm no standalone expert... I imagine it will depend on what sensor inputs have what effect on your map.

 

[speedfreak]

thanks colin i think i will have to keep the isc then which will be controlled by the tccs, im planning on running half stand alone and half tccs. my ems controlls tps, map, air temp, water temp, injectors, spark with halltech sensor(timing). but the rest im gonna try and leave to the tccs like rpm, gauge cluster, isc,etc everything except what the ems does. my ems is a sds em3-f i dont think anyone on here has used one, but anyone think this is a bad idea? i know the tccs is going to be throwing some serious codes lol!

 

[mkIIIman089]

Some parts will definitely be tricky, you're going to do a lot of reading of Toyota literature, and oscilloscoping to keep it working.

 

[Poodles]

It's a stepper motor. This might give some insight to how the TCCS works: http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=044

 

[speedfreak]

thanks that might help, do you think the tccs will malfunction without being plugged into the coil pack and injectors? thats basically all im leaving out i just want my guage cluster to stay the same.

 

[hvyman]

The cluster is wired through the body harness not to the ecu. Gets its inputs from the sensors.

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=136

If your contolling the engine with the non stock ems ditch the stock ecu.

 

[speedfreak]

done, thanks

 

[IJ.]

Stock ISC is a Stepper as Poo noted, depending on how it's wired it can chew up 4>6 AUX channels in your aftermarket ECU... this sucks, I made a flange for a buds 7M to mount a 2 wire Ford Solenoid so it only needs 1 x channel to run it.

 

[tweak666]

i'm a soon-to-be sds user too! same system as well. Have yet to delve into wiring it up, still toying with hall sensor placement

 

[speedfreak]

i would have put the magnets on the back of the pulley but it was already made when i got it. then you have to run the timing curve backwards which is confusing ie 25degrees aftdc @3000rpm or so

 

[tweak666]

have any pics of your setup?

 

[speedfreak]

i can take some if you need let me know have it working perfect now. i love this system you should use yours