MSII sensor/wiring install

[KurtW85]

First, MSII V3.0 board...i have the diyautotune wiring harness, its all laid out and im ready to solder my sensor connectors on...

its setup for a stepper(iscv) motor and i was wondering how you guys wired it in?
http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?Section=FI&Page=61

The b1 and b2 terminals to a igniton power source??? and then wire the four striped ms wires according to there numbers to the toyota ISCV?

Im utalizing the stock toyota temp sensor aswell:
which terminal is the ground?

TPS...
http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?Section=FI&Page=63
Im totally confused on this all together... there are two wires on the ms harness.... and four on the stock harness... ???

IAT...
Iam using the open GM IAT...which terminals are which?

Injectors...using 440s...
lost on this one...someone???

THANKS!

[Darrow]

From my understanding the temp sensors act as resistors and it doesn't matter which side is ground.

For the iscv there are two sets of windings. If you look at the previous page you can see them and see which connectors they go to. I am having confusion on this as well and I think that it will need to be bench tested to see if polarity matters. That is + needs to be on a certain side.

On the MS from what I can remember (I don't have it infront of me), the throttle position is measured by resistance from the TPS. IDL is not used. E stand for earth and that is of course ground. That is used. I think the VTA is used. You shold need to do a resistance check in order to calibrate the TPS. You can see by the resistance readings which ones need to be used. VTA to E2 has a reading for fully closed and wide open.

For the injectors I don't think polarity matters, not sure though. all the ecu is doing is connecting the circuit to ground therefore energizing the injector and opening it. ECU disconnects ground injector goes shut. There is a coil in there so my guess is that the current induces a magnetic field in order to move the plunger. The direction of current will change the polarity of the field. Reverse north and south. if the plunger is magnetized then the + and - will matter if it is not magnetized then they won't matter.

I am doing a plug and play with the stock harness. I will look at my notes over the weekend and see if I can provide better explanations. Basically if it getting a resistance reading the polarity doesn't matter. I think polarity matters on the ISCV because the windings induce a current and the direction of current matters.

[RedP85]

stock toyota temp sensor, which terminal is the ground?
> brown wire

TPS...
Im totally confused on this all together... there are two wires on the ms harness....
>depends if the MS is expecting resistante to increase with pedal going down,
or decrease..
> need increasing R, use VTA & E2.
> need decreasing R, use VTA & Vc.

[KurtW85]

thanks so far guys. my buddy is letting me borrow his extra megastim. hehe, its sweet. im officially addicted to this stuff. man. ahhhhhhh. i don't have a serial-usb adapter yet. its gonna be a good ole search for one tomorrow. man. gonna drive me nuts.

[Darrow]

All of my notes were in my EWD, which I can't find at the moment. I will keep searching.

Keep us updated.

[SuperSubs]

for the throttle positioning sensor, for what I used, in the original harness, connect the brown wire as the ground, the black wire is the sense wire for the signal, and the blue/red wire is the 5v+ vref signal... and the fourth wire is not used. Make shure you callibrate the throttle positioning sensor anytime you do any kind of ignition or altogether modifications, it only takes two seconds with megatune, and you'll find that the values will shift slightly from time to time. As for the IACV, I never utilized mine, just blocked it off to save time, but may experiment with it more when I have time. Also a helpfull hint, ground ALL your sensors on a seperate line and ground at an engine point (aka, somewhere like the original ground on the distributor bolt), this will save alot of headaches with incorrect values and noresposive sensors, if you forget to extend a ground for the sensors on the harness. Good luck!!!

[RedP85]

.. somewhere like the original ground on the distributor boltI don't think this bolt is a good idea.
It is left loose while adjusting 'base' timimg, and beeing loose at that time is not recommended.

[SuperSubs]

I don't think this bolt is a good idea.
It is left loose while adjusting 'base' timimg, and beeing loose at that time is not recommended.

Very good point, now that I think about it, I never liked that ground either on my original harness, it seemed like it just wasn't long enough and was a bi*%h to get it on that bolt.....

[SupraWes]

Its supposed to be on one of the intake manifold bolts where the 2 halves bolt together not on the distributor.

[KurtW85]

so i should just wire each individual sensor to its own ground, and then ground them all at a common place, like the factory location on the intake mani as wes said

[RedP85]

:good:

[KurtW85]

sweet, im actually in the garage right now workin on my harness...i love this lap top...lol. well heres what i did as far as ISC valve:


On a V3.0 main board,

* (1A)JS0 (under the processor socket) to IAC1A (near the DB37 connector) - this goes to Coil 1, lead A on DB37 pin 25
* (1B)JS1 (under the processor socket) to IAC1B (near the DB37 connector) - this goes to Coil 1, lead B on DB37 pin 27
* (2A)JS2 (under the processor socket) to IAC2A (near the DB37 connector) - this goes to Coil 2, lead A on DB37 pin 29
* (2B)JS3 (under the processor socket) to IAC2B (near the DB37 connector) - this goes to Coil 2, lead B on DB37 pin 31
* Install a jumper from the hole marked S12C to the hole marked JS9 (+12C)

If you are using the relay board, and have connected the wires for the IAC to DB37 pins 25, 27, 29, and 31, then:

* 1A goes to S1 on the 20-position terminal strip of the relay board,
* 1B goes to S2 on the 20-position terminal strip,
* 2A goes to S3 on the 20-position terminal strip,
* 2B goes to S4 on the 20-position terminal strip.

I pretty much did the last step. i read it as the same as above, except it actually uses s1, s2, s3, s4....and 1a 1b 2a 2b....it made sence to me, and ironically it seemed to be straight from the tsrm.
http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?Section=FI&Page=61

so i just made sure to follow and put together the testing process with the 1a, 1b, 2a, 2b ect... so hopefully this should work. right??? i could've confused myself. lol, but nit seems pretty logical. ALSO the other 2 wire connector from the ISC-V is the power wires right? where to get power for that and injectors?

I have the rest of the harness done besides these...and its nice :) i used all factory plugs so itll look nice hehe. and im lovin it.

[Darrow]

by looking at an EWD you will see that the power for the injectors come from a switched 12v power supply through the resistor pack to the injector then to the ecu. So I would say you will be fine with a switched power supply.

Same for the ISCV power comes in to the B1 and B2 from a switched power supply then to the ISCV and ecu.

[KurtW85]

can someone give me a good example of a good switched power source? And my next question, the distributor receives two wires. the gray "IGN" wire and the black ground, both 14ga. I have an '82 vac distributor modded to work on ms vr setup, what wires are positive and ground on the distributor?(brown, white?) Im guessing brown for ground...

im also wondering where did you guys hook up your:
"fuel pump"
"12vcd"
and i assume the pin 36 wire goes to the neg side of the coil for direct coil control? explanation?

[KurtW85]

i just got my megastim and serial-usb adapter working...it appears i am dumb, and after reading threw the mega manual a shit ton i found out how to actually upload and install the software the right way. yay. its pretty sweet. hehe. ill be in school in less than four hours...going to sleep now...

[cheappower82]

can someone give me a good example of a good switched power source? And my next question, the distributor receives two wires. the gray "IGN" wire and the black ground, both 14ga. I have an '82 vac distributor modded to work on ms vr setup, what wires are positive and ground on the distributor?(brown, white?) Im guessing brown for ground...

im also wondering where did you guys hook up your:
"fuel pump"
"12vcd"
and i assume the pin 36 wire goes to the neg side of the coil for direct coil control? explanation?

switched power - anything hot while cranking and running (ie: resistor pack for injectors)

distro wires: vr wires are AC. polarity may be an issue, so you may have to swap them around if you can't tune it out.

grounds: run several everywhere, to the block, head, firewall, battery, and make sure to strip the paint from the chassis or other metal surface. megasquirt is very unforgiving to grounds

fuel pump: mine isn't setup properly, but i have the fp connected to the b+ on the stock ecu connector and a jumper on the afm connector (can't remember which pins; i'm in atlanta for the week). basically my fp is on when the ign switch is on------bad idea i know

[KurtW85]

well what wires did you hook to what regaurding the distributor? brown and white... im using the one you sent me. also how do i lock it out? i took the vac advance off...what else do i need to do? does it have a mech vac advance as like a back up or something?

also, as far as wiring for the dash harness that goes to the ecu...what do i make of that? in the link you sent me it has a pic of the factory ecu hooked up...

[williamb82]

tech you could use a 4 wire relay to jump the connector by the afm when the ms tells the pump to run, but would be better to trip the actual fuel pump relay. also, doesnt the large ecu connector under the dash have a +12v switched that is on when engine is cranking? i had planned to use that to power my megasquirt. just dont recall which pin it is at the moment. maybe ill put a batt in the 84 and check those with my multimeter while cranking this weekend to find out for sure. also, what source would you recomend to power the edis module? id want a switched source near the fuse box that stays on while cranking.

[KurtW85]

::cough:: Pistons are here::cough::

:iocrunks2:

[935motorsports]

kind of unrelated, but does the MS have a fuel pump output that shuts on and off with the car?

I assume no, by what you guys are saying there.

[Darrow]

kind of unrelated, but does the MS have a fuel pump output that shuts on and off with the car?

I assume no, by what you guys are saying there.

Yes if you wire it like that. It depends on how you wire it in.

[935motorsports]

ok good info thanks