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View Full Version : got an electrical question *schematic included*


madking411
10-09-2007, 08:34 PM
I know, people talk about the IAT mod like it doesnt work and stuff, but i tested it a while ago, and i KNOW for a FACT it works. And i also know that you shouldnt leave it on all the time or else it could screw up the ECU and make the engine become too rich all the time.....so, what i want is a way to compensate; Have the IAT mod on when i want it, off when i dont. So, this means that i need to put in some sort of switch in to turn it on whn i want to, and have it work normally at other times. So, i thought up a little bit of a schematic, and im not sure whether or not it would work. PLEASE. CONSTRUCTIVE CRITICISM or USEFUL INFORMATION or ADVICE ONLY. If you have something stupid to say, get outtta my thread before you push that 'Post Reply' button.:mad:
Anyways....here it is....
http://img77.imageshack.us/img77/9789/iatmodux0.jpg
dorin48
10-09-2007, 09:00 PM
You need to rethink your schematic. Based on your diagram if you switch it to "off" that would turn off the sensor completely not just bypass the resistor(which is what you want). That would throw you CEL.
madking411
10-09-2007, 09:22 PM
YEah.....after i drew this, i looked in the Haynes manual at the wiring diagrams...i'll draw another one...
madking411
10-09-2007, 09:36 PM
Will this work?? (re-drawn..) Oh, and by the way...please be patient with me, i've never REALLY made up my own schematics before...:thinking:

This is out of the Hayne's Manual. (Everything thats not in color...)

http://img406.imageshack.us/img406/3801/iatsensordk2.jpg
madking411
10-09-2007, 09:59 PM
bumpump....more advice please..
IDriveToast
10-09-2007, 10:38 PM
Im not sure how you would do this with one switch. It is possible with two switches tho.

You would have to basically run an extra wire to a second switch for the signal wire.

It would be something where you flip the first switch to interrupt the actual signal wire (causing 0v signal). And then flip the 2nd switch to active the wire with the resistor in it.
madking411
10-09-2007, 10:40 PM
Im not sure how you would do this with one switch. It is possible with two switches tho.

You would have to basically run an extra wire to a second switch for the signal wire.

It would be something where you flip the first switch to interrupt the actual signal wire (causing 0v signal). And then flip the 2nd switch to active the wire with the resistor in it.

Hmmm...i may try that....

do you think you could draw me up a picture or somethin??

Oh, and will my 2nd drawing work, or not...??
IDriveToast
10-09-2007, 10:48 PM
eh, tried to draw it on here and it wont let me. Oh well. GOnna try paint.
madking411
10-09-2007, 10:50 PM
yeah, do it in paint and save as a jpeg. then put it up like a normal pik


Thing is....i wanna know...WILL MY SECOND DRAWING work or not?
IDriveToast
10-09-2007, 10:56 PM
http://i195.photobucket.com/albums/z30/IDriveToast/untitled.jpgIm not sure if your 2nd drawing will work as it doesnt really bypass the original IAT sensor wire.

This one works if you flip switch 1 to cause an open circuit and then flip switch 2 to close the circuit and send the signal altered by the resistor to the ecu.


edit: and to answer your question about your 2nd drawing. You aren't interrupting the signal sent by the original IAT wire with just that 1 switch. So it wouldnt actually *change* the voltage reading sent. So, no..I do not believe your second drawing would work.
madking411
10-09-2007, 10:57 PM
But, my switch that i have has 3 terminals on it...thats why i only wanna use one...

Because, i think ill have it set so that when 2 of 3 terminals are ON, they'll either lead to a circut with the resistor, or if its switched to the other 2 of 3 terminals, it'll lead to wires withOUT the resistor in it, and it'll run normally...:thinking: On PAPER, it looks good i think....
IDriveToast
10-09-2007, 11:03 PM
Your schematic doesnt work tho...if you have a switch with 3 terminals (By terminals I mean connections on the back of the switch) it could look something like this.

This would be a switch where it would flip between 2 different terminals on the switch.

It may work if you switch is this kind.


http://i195.photobucket.com/albums/z30/IDriveToast/untitled2.jpg
madking411
10-09-2007, 11:05 PM
That looks like EXACTLY what i want. And i think thats right too, cuz my switch has 2 different modes on it. But, it has 3 terminals, and 2 out of 3 are always selected, so its got 2 modes.....

So, the 2nd drawing YOU made is basically what i WAS trying to draw. Will THAT work??
IDriveToast
10-09-2007, 11:06 PM
It will work as long as your switch is the kind Im thinking of. What will happen is it will just flip between the two signal wires. When one is a closed circuit, the other will be open.
madking411
10-09-2007, 11:08 PM
http://www.germes-online.com/direct/dbimage/50306189/Rocker__Switch.jpgThis is BASICALLY what i have. Only difference between mine and this is that mine doesnt have the ''O'' and ''I'' on it. Its got the 3 terminals and everything
IDriveToast
10-09-2007, 11:12 PM
You can test your switch and see. It's not too hard to do. So you don't waste time installing it and find out it doesnt work.

Just use a 9v battery or a drill battery of some sort and a multimeter.

Attach a wire to one post, and then to the battery. Check the voltage at the other two posts. Then flip the switch and see if the voltage changes.

Then attach a wire with a resistor in it to the other post and check the voltage again to see if it has changed.

It's better to test it before you put it in.


As I said before Im not sure what kind of switch you have. Just because it has 3 posts doesnt mean it will flip between the two wires.
madking411
10-09-2007, 11:14 PM
welll....looks like ive got something to buy...a multimeter....
IDriveToast
10-09-2007, 11:16 PM
Or....go ask for a switch that isnt a ground type and will flip between two signal wires :D
madking411
10-09-2007, 11:17 PM
One more thing actually....in the haynes manual, it said that the wires are tan and grey....i KNO in real life, on my car, the wires are red and black...+ and -.....Which one would i be tapping?? the positive or the negative??
IDriveToast
10-09-2007, 11:20 PM
Not sure on that one. Ive never really worked on a pontiac. But wiring is wiring :D As far as the colors go, Im not sure. Looks like something you'll need to do a little research on.
xbn83
10-10-2007, 03:21 AM
Don't use switch at all! Put a Potentiometer inline with the ECU input signal wire. You have to figure out what ohm range of the potentiometer to buy. Read up on what is potentiometer! Basically it is a variable resistor. I've done this mod 7 years ago on my very first car.
madking411
10-10-2007, 05:17 AM
I already kno what it is....and i know how much resistance to put in already...

i just need to know how to wire it all up..
japan4racing
10-10-2007, 08:44 AM
use of a relay will simplify this so much. just use one switch and a relay and you got yerself a done deal. the poteniometer is not a bad idea either. i now you dont wanna hear this but why not save the time spent and do a mod that matters more?
singsifu
10-10-2007, 10:31 AM
nice
madking411
10-10-2007, 01:41 PM
I'll use the potentiometer.....im just about to go get it...

And, the reason i dont save up for a mod that matters is because i dont have a JOB yet......im workin on THAT too....lol
madking411
10-10-2007, 04:47 PM
NOW. how do i wire up the potentiometer into the rest of it?? it has 3 terminals on it.
xbn83
10-10-2007, 04:55 PM
If I remember correctly, you will only use 2. Which 2, I don't know. You have to use a volt meter, touch 2 terminals of the potentiometer at the same time, rotate the knob of the potentiometer back and forth to see if the resistance changes. If not, continue until you find the right 2. After you find the right 2, simply cut your signal wire from IAT, each end hook up the the 2. I hope you bought the right ohm range potentiometer.
madking411
10-10-2007, 05:41 PM
yep i got it-- it works PERFECTLY too.....i didnt use a mutimeter to tell, but...i knew when i had it off vs. on, because when i had it ON, i could smell the car's exhaust a little bit heavier...and it was a little more pungent. My engine can handle it though, because there was no black smoke out the back, and the idle didnt REALLY change much.....maybe just 100RPMs different at idle...

lawl, and i could feel it on the butt dyno just a TINYTINYTINYTINY amount....but i DID feel it. I took two drives around JimmyCarter and BufordHighway and back to my house...with it on, my car also is more responsive when i abruptly step on the gas.