: T/C cut out assembly



danbuc
10-29-05, 09:52 PM
Well, I finally got around to building the T/C cut out unit that Mark99STS' friend had designed. It mount inbetween the 4/pairs of wires that lead from the 4 ABS sensors to the PCM. It will allow the user to switch between the ABS senors, and 4 1k ohm resistors which trick the computer into not engaging T/C. I drew up a wiring diagram to sort of explain how it's put together. It's a little rough around the edges, but gives a pretty good idea. I'm also going to include a pic of the unit itself. As far as connectios go, I descided to use 9 Pin serial connectors. I also used 4 DPDT 6A 12vdc relays from radioshack, as well as a small blank bread board to mount everything to. I'm going to finish the install tomorrow by accessing the ABS module, and hooking this unit up. I'm going to run a switch into the cabin, as well as an LED to indicate that the unit is on.

Ranger
10-29-05, 10:01 PM
WOW, that seems like a lot of work just to disable T/C. None the less, I am impressed. I can make a water pump socket, but you have me lost here.

lry99eldo
10-29-05, 10:29 PM
You freaking electronics guys!!!!!! I don't even understand a AA battery, let alone figure out how the T/C electronics work. Good luck and good job!
lry99eldo

eldorado1
10-30-05, 01:38 AM
umm... so you switch between the wheel sensors and a 1k resistor? You're going to set 4 wheel sensor codes when the PCM sees the engine rotating, the output shaft rotating, but no wheels rotating.

What you'd want to do is tie one of the front wheel sensors' outputs to the rest of the inputs. The PCM detects loss of traction by comparing wheel speeds. When one or more is out of line, it cuts power. Tie them all to one wheel, and by definition they'll be the same speed. And you don't have any codes either. (which may or may not enable traction control by default, I don't have my book handy)

danbuc
10-31-05, 10:53 PM
Umm..yeah, I kind of realized where I went wrong when I hooked it all up and it was throwing codes like it was on fire or something..hehe. I'm going to correct it by taking one input and splitting it off to all four N/O contacts. That way it will just switch between either all four, or just one, runing to all four. The way I had it setup now, was supposed to function liek the setup Mark99STS was talking about. Instead of shoving a 1k ohm resistor in each ABS sensor connector, I was gonna run it through this thing. Your idea of just switch form four seperate inptus to one input is more logical, and simpler though. I'm going to wip out the sodering iron tomorrow night and take another look at it.

fubar569
02-28-06, 06:34 PM
i think i see where your diagram went wrong, but it is a little complicated and tough to decipher.

i didn't know anyone else had made an attempt to replicate that unit. i'm workign on it right now.

your idea with 4 1k ohm resistors was throwing codes? there must be some sort of error in assembly maybe? perhaps did you cross wires of some sort?

i know it's been awhile, but where does your progress stand?

danbuc
02-28-06, 10:00 PM
Well, I think it all went wrong when I only hooked up one sensor through the box. I just wanted to see if it would still read the signal running through the box, but I didn't want to do all four since it was late. I ended up splice into only one circuit and runing the other three direct, and I think that's what caused it. As of right now, my progress has more or less completely haulted, since the I only have the two connectors that plug into the box (I left the box back home in NJ, 'cause I forgot about it when I came down here).

peteski
03-01-06, 04:24 AM
I don't think there is assembly error. If the computer stops seeing AC pulses from the wheel sensors (because you just plug a resistor into the circuit), it will cry that something's afoul!

Because the 'puter expects that the car is moving, so it wants to see pulses.

I think that your best bet is to connect all 4 inputs to a single wheel sensor (which will trick the 'puter into thinking all the wheels are spinning evenly).

But having one sensor driving all 4 inputs might put too much load on it and this won't work. So, you might need to build some sort of buffer or an amp which will boost the signal before passing it to all 4 inputs.

I'm glad to see that the art of hardware hacking is still alive and well. I thought that in the age of miniature SMD based circuits this was pretty much a lost art. Well, I was wrong.
Awesome!

Peteski

MARK99STS
03-01-06, 02:05 PM
I don't think there is assembly error. If the computer stops seeing AC pulses from the wheel sensors (because you just plug a resistor into the circuit), it will cry that something's afoul!
Peteski

Wrong! At least on a 99 STS and I assume on others.The traction control works by monitoring all four wheels to detect excessive spin differential between any given wheel. It is looking for resistance to verify that the sensors are plugged in or working for self diagnostics. What the resistors replicate is basically that the car is standing still and all four wheels are not moving. There is no correlation between engine speed, rpm, tail shaft or other info. It simply monitors changes between the wheels. We tested it by putting the car on jack stands in the front only and putting it in gear and giving it gas. With everything stock, as soon as you get to about 8mph with the back wheels not turning, the ABS kicks in and the "traction control engaged" comes on the dash. If you unplug a sensor, it defaults to 2nd gear and the ABS light comes on. When you plug a 1000 ohm resistor in each sensor plug, the computer thinks the sensor is working because there is resistance, but it thinks the car is not moving as there is no signal.

peteski
03-02-06, 01:51 AM
Allrighty then - lets see if danbuc can make it work just using resistors. I thought that the 'puters were "smarter" than what you describe.

I don't know how the computer reacts to various inputs. - I was just speculating.

We now just have to wait and see...

Peteski

fubar569
03-02-06, 01:57 AM
see my other thread, i'm working on the same relay box right now but using a PCB and 5 relays because i'm also increasing line pressure in the trans and activating a light so you know the box is on. i have pics and a running cost list. i also plan on making more for others on a per order basis once mine is complete and verified working

CadillacSTS42005
03-02-06, 10:48 AM
way to go fubar how much do you estimate for the cost?

fubar569
03-02-06, 02:02 PM
so far for my personal unit i'm up to about 25 in parts, but i've only paid for 1 relay so factor in another 21 bucks for 4 other relays plus the connectors & wire...mine will be much more than others.

other units probably will not have the 5th relay and well be setup cleaner. i'm also not passing on my inital costs to anyone so parts alone will probably ballpark 50ish bucks not counting the wiring which i haven't sourced yet. I'll be including a very lengthy harness to aid in mounting locations and ease of installation. all you'll really have to do is tap into the wires on the ABS unit, run a 12v switched source & ground, the indicator light and be done.

everything is in my other thread. danbuc's even been over there i think. he also let me know in a PM that his box isn't with him right now and he's looking forward to seeing the results. also i recieved word from Mark99STS that the idea was jointly formed between him and his buddy so i must give credit to them first and foremost.

STS 310
03-02-06, 11:28 PM
Well I dont know much about electronics, but I do know that manufacturers that use them will use the basics most of the time. A very complicated set up for wheel spin management doesnt have to be therefore why spend the money?

I am very confident that many members will find easy ways to disable
TC. OBD II is another story. (I cant figure out why though?)

I guess its not an ATM or the IRS mainframe.......

fubar569
03-03-06, 06:20 AM
it's not so much that i'm trying to make it complicated as i'm trying to make it convienient. you can disable it for 99 cents (the price of the resistors) but personally i do not wish to crawl underneath my car with the wheels off everytime i wish to enable/disable traction control. wouldn't a switdch be much easier and overall worth the price? i think so...

CadillacSTS42005
03-03-06, 01:56 PM
i agree i dont mind workin on my car but doin that over and over will become repetitive and anoying and if im out driving and it starts to snow or rain? id love to just flick a switch and have my tc back on

danbuc
03-03-06, 02:49 PM
I didn't add this to this thread, but I did notice something interesting the other day when I tried just putting the four resistors in each connector. I was in a rush, as I was on my way to the track. After I installed the four resistor (no codes were displayed, eveything seemed fine) I realized that I had to pick my friend up before I went to the track. Getting my friend meant getting on the highway. As soon as I got the car up to speed, I noticed that my steering was very touchy, an would almost turn the wheels if I just looked at the steerign wheel the wrong way (liek my old mustang). I suddenly realized that with the car thinking the vehicle was not moving, the Speed Sensative Steering didn't work. It basically was set to maximum assist, which which is the worst thing you can have on the highway. I almost ran of the road twice, while trying to change lanes, since I oversteered too much. Needless to say, I got my friend, stopped back at my aoartment, and quickly removed them before hitting the track.

I'm not sure if it's just 1998, or other years...or even other cars that will do this. My suggestion would be to try and use an input from one wheel. That way, if your on the highway and the box just so happens to turn on (i.e. short, somebody messing with the switch,..ect) you don't run the risk of steering into the gaurdrail or car next to you while trying to make a turn.

fubar569
03-03-06, 05:01 PM
i guess that's what happens when we rely too much on those systems. my 77 corvette ws the same way but i adjusted...i can now hop in any car i have and know how it's gonna act, because i took the time to learn them in all conditions...

i can make 2 versions of the unit. theoretically the layout i have now will work with only running a few jumper wires from sensor 1 to the other normally open contacts. this should be very easy to accomplish and take minimal time to convert. it will work as a temporary patch till i figure out a layout to incorporate that into the board.

peteski
03-06-06, 04:26 AM
I'm not sure if it's just 1998, or other years...or even other cars that will do this. My suggestion would be to try and use an input from one wheel. That way, if your on the highway and the box just so happens to turn on (i.e. short, somebody messing with the switch,..ect) you don't run the risk of steering into the gaurdrail or car next to you while trying to make a turn.

Thanks danbuc - this confirms what I suspected in my earlier post. The ABS wheel sensors are used for other purposes than just ABS and TC.

Assuming of course that other cars will act the same (but why wouldn't they?)

Peteski

fubar569
03-06-06, 05:38 AM
something i'm gonna work on for people is an additional plug that say (on the sheer 1% chance) something goes wrong with the unit, you could plug this connector into the harness and resume normal operation until the box is repaired. basically it'll be a DB25 connector with the right wires jumpered to just close the connections so they are as normal...

i can see everyone's point with the "what if" the switch is bumped on or something, but if placed in the right spot this should not be an issue. a better idea would be to mount it out of the way but yet with an "arming" cover similar to a nitrous switch. Also, that's what the LED indicator is for, to let you know when the box has power...

i'm making very good progress. it's already had it's first revision and the wiring "harness" is about 50% done. i wish my local radio shack actually replenished stock on a regular basis!

MrEr1c
03-08-06, 01:24 AM
i can see everyone's point with the "what if" the switch is bumped on or something, but if placed in the right spot this should not be an issue. a better idea would be to mount it out of the way but yet with an "arming" cover similar to a nitrous switch. Also, that's what the LED indicator is for, to let you know when the box has power...

like a "military" style switch.

I have yet to actually dig in to my car but how difficult ould it to mount/install on of these swtiches in say maybe the center console where the cd changer sits? or even the center cig tray?

gl

fubar569
03-08-06, 03:05 AM
it would be cake, though i'm thinking of using the cig tray for the nitrous. my dash kit for the stereo provides the nice empty pocket upon which i could fab a plate and all the switches i'd ever need would fit right there.