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2JZGTE swap this summer...

Connected a ground and found a plug that I didn't plug all the way in, which was keeping my ASD output from getting power to the alternator and fans. Vehicle is charging and fans are running. Just took it around the apartment complex again and watched her start to make boost. got up to about 7 before I let off. She is still not shifting. Ground to the VSS in the transfer case is good, and power shows 3.7 volts, which seems a little strange. My all data isn't telling me what this voltage is supposed to be however. Anyone know if this is a 5 or 12 volt power 4-pulse speed sensor? In the mean time I need to get this wired for manual shifting. Wish I could find some sweet paddles, lol.
For now I want a stick that is momentary up or down, so I can shift through the gears accordingly sequentially.
 
which VSS is that? Jeep or Toyota? The Jeep one is 5 volts IIRC.
 
Yeah, in fact I found out I AM in fact a retard and connected the power to the sensor to the wrong pin on the ECU. In discovering that, however, it looks like the Jeeps are between 5 or 8 (year dependent), but the Toyota is 12v. Keeping in mind that voltage is what the respective ECUs want to see, any one care to bet on whether or not the Jeep sensor will throughput 12v just fine? :) Continuing this tomorrow.
 
I'd bet against the jeep sensor handling 12 volts, it'll probably release magic smoke.

You could build an adapter to convert the signal to 12 volt pretty easily if the ECU is expecting a 12 volt square wave type signal. Depending on the logic in the ECU it may not even matter, the ECU may see anything above a few volts as an "on" signal.
 
Super mud said:
Yea your dumb as shit, kill your self.

I Didn't know toyota's system was based on 12volts, interesting.
Click to expand...


You guys have no idea how angry I can get at myself. Maybe not angry, just frustrated and disappointed.

Bloodhound Gang just started playing in my head now, I'll have to you tube it.
http://www.youtube.com/watch?v=mhyVIluOwKg

Anyway the Toyota TPS and MAP sensors are 5v powered by the ECU, but apparently the vss pulses 12v to the ecu. I'll start by connecting the vss to the same 5v sensor power and see if the ECU will recognize it. If not, I'm gonna give it EFI power instead and hope the vss can take it. I'm actually pretty sure the vss will, since it's not so much the voltage that burns things up, but the current. Since this is very little current and merely sensing the voltage puling, I think it will be fine. Tomorrow I should know...and so shall you.
 
child9 said:
You guys have no idea how angry I can get at myself. Maybe not angry, just frustrated and disappointed.

Bloodhound Gang just started playing in my head now, I'll have to you tube it.
http://www.youtube.com/watch?v=mhyVIluOwKg

Anyway the Toyota TPS and MAP sensors are 5v powered by the ECU, but apparently the vss pulses 12v to the ecu. I'll start by connecting the vss to the same 5v sensor power and see if the ECU will recognize it. If not, I'm gonna give it EFI power instead and hope the vss can take it. I'm actually pretty sure the vss will, since it's not so much the voltage that burns things up, but the current. Since this is very little current and merely sensing the voltage puling, I think it will be fine. Tomorrow I should know...and so shall you.
Click to expand...
The problem lies in the fact that the VSS is an active component (actually a Hall effect sensor and a preamplifier and logic level converter + line driver, but I digress) that's designed to handle 5 volts. I'm not entirely sure that it will smoke if you feed it 12 volts, but there is a good chance it will. Many 5 volt powered integrated circuits are designed to operate properly from 4.5 to 5.5 volts, with an absolute max rated voltage of 7V before magic smoke starts coming out. And it's pretty hard to put the magic smoke back in once it comes out...

I believe *some* years of VSS for XJs/MJs are either VRM style or reed switch style rather than hall effect, since the one in my '91 has only two pins (an active VSS for a 95/96 and later has 3 pins - 5 volts, ground, and signal return), but I am not entirely sure. Those should work fine on 12 volts, since they are simply using the voltage supplied as a reference.
 
Can't edit my above post, so I'll add this here. Based on at least two individuals strongly feeling that the Jeep VSS won't take 12v very well, I'm going to go the proper route and build a plug-in op amp that will take the Jeep 5v VSS signal and make it a 12v signal to send to the ecu. Looks like I'll be making a trip to Radio Shack tomorrow. Researching this now.
 
The Jeep VSS will smoke if you apply 12 (well, really 14...)VDc to it. All the the Heep sensors are 5VDc rated. A dedicated, regulated. conditioned, pretty darn clean, 5VDc.

Keep in mind that the VSS develops a square wave as it's output and the ECU translates the frequency to drive the speedo. Make sure the OP Amp will cover the frequency spectrum (typically 1Hz to 244Hz) required.
 
A little off topic, but where have you guys (Kastein, O-guage, Child9, et al) picked up your electronics skills? Community colleges don't seem to offer in depth electronics work around here.
 
I have the 3 wire version I'm using from the transfer case...I just plugged the hole in the actual trans where vss1 would normally be, since the sensors are not interchangeable.

Personally I just build shit and learn as I go...although I have taken a basic electronics course like 8 years ago, which is a good place to start. Everything else I need to do I just study, learn it, and build it. I'm in school working towards an BSME, but that's just to help me do what I do and give me tools for my mental tool box, I gives no XXXXs about the piece of paper at the end. Too many times I take a class knowing what I want to learn only to realize that they barely brush on it, and often the teachers don't really know real-world apps. This is why I have one unique Jeep. :) Should I KIT this setup? Hmmmmm....
 
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o-gauge-steamer said:
The Jeep VSS will smoke if you apply 12 (well, really 14...)VDc to it. All the the Heep sensors are 5VDc rated. A dedicated, regulated. conditioned, pretty darn clean, 5VDc.

Keep in mind that the VSS develops a square wave as it's output and the ECU translates the frequency to drive the speedo. Make sure the OP Amp will cover the frequency spectrum (typically 1Hz to 244Hz) required.
Click to expand...
agreed. Though you'll be hard pressed to find an op-amp with a gain-bandwidth product of under a few hundred KHz these days. I would likely use your vanilla LM324 quad comparator or maybe an LM358, LM741, LM339 (open drain output, so you need a pull-up resistor), or MC1458 (same as an LM358) if you have them on hand.

yossarian19 said:
A little off topic, but where have you guys (Kastein, O-guage, Child9, et al) picked up your electronics skills? Community colleges don't seem to offer in depth electronics work around here.
Click to expand...
Well... I got interested in electronics at age 7 and knew how most basic components (resistors, capacitors, inductors, transformers, diodes, transistors) operated before I could read. Basically taught myself using various Forrest Mims electronics books and old college textbooks till I was around 14, then started EE and math courses at the local community college. I've got an associates in EE and a bachelors in ECE (elec/computer engineering.)

TL;DR: I am an electronics nerd and have been for nearly two decades. When I'm not working on my house or jeeps, I'm usually either building something electrical or reverse engineering something electrical.
 
they're based off the way the VSS works. Effectively it's (driveshaft revolutions per second) / (output shaft worm gear to VSS gear tooth ratio) * (VSS pulse per revolution count). Toss in your rearend gear ratio and tire size and you can calculate how many feet of ground you will cover for each pulse from the VSS.

That being said, the signal is a square wave, so your amplifier needs to accurately pass several harmonics of the VSS signal fundamental frequency (at its maximum) to give a signal with a decent rise time to the ECU. I would not worry about it though, even assuming the VSS cranks out 1kHz at your max speed (almost certainly way high) you have PLENTY of space before your op-amp or comparator stops producing gain.

Should be a fairly simple circuit to design. Since an op-amp or comparator effectively just increases or decreases the voltage on its output until the voltages on both its inputs are the same (whether it increases or decreases the output voltage depends on whether the inverting/- or noninverting/+ input is higher than the other) all you need to do is power the comparator off your 12 volt supply, feed one input the signal from the 5V powered VSS, and the other input approx. 3-4 volts DC. I would use a 1k ohm resistor to the VSS 5V supply and a 3.9k ohm resistor to the VSS ground to create the 3-4 volt DC reference voltage.

Depending on whether you feed the reference voltage to the - input or the + input (and the VSS signal to the other) this circuit will either invert the signal and convert it to 0-12 volt square wave, or simply convert it to the 0-12 volt square wave. I doubt it matters too much.
 
yossarian19 said:
A little off topic, but where have you guys (Kastein, O-guage, Child9, et al) picked up your electronics skills? Community colleges don't seem to offer in depth electronics work around here.
Click to expand...


In 1964... I started with Short Wave Listening. As I did not come from a family with money, I picked up my equipment from the Army/Navy Store (Yes, Virginia, the AN Store was selling military surplus. Really.) and had to learn about radio in order to get them to work. Amazing how if you move the position of an old school capacitor under the chassis, the signal strength changes...

In 1968, I started working on Computers. Yup, MAINFRAME computers with 96K of RAM...

In 1975, I formalized my education via DeVry...

By the 80s, I was a Senior Field Engineer for a Major CNC Machine Tool Manufacturer.

Mid 90s, I had transistioned to a Senior Process Engineer as I needed to get off of the road.

Retired in '08 due to health issues. Not my idea at all...

Thing is, the information is out there if you want to educate yourself. Check your library for the reference books.
 
child9 said:
Where are the frequency numbers coming from?

I have a Dakota Digital speed signal modification unit, but I think it only varies pulses, not voltage. It is, however, powered. Maybe I should call them.
http://www.dakotadigital.com/index....tegory_id=287/home_id=59/mode=prod/prd126.htm
Click to expand...


I am using my AEM F/IC8 to alter the frequency that the PCM is seeing in order to correct my speedometer/odometer. This ability is why I picked the F/IC8 over the F/IC6 to begin with. Given the cost of a quality aftermarket piece of electronics, It was less costly to get the F/IC8..

You are correct that the voltage does not change. 5VDc. It is the frequency that is changed. In my case, I have a -10.9% correction in the frequency table to correct for 4.56:1 gears and P285/75R16 tires. BTW, I installed a Dakota Digital unit in my 97 back in 2001. Went this way as I had to deal with the fuel/ignition issues on the Supercharger anywho. Lets face it, changing gears in the TC only gets you so close. For us AR types, close is just not good enough...

The frquency range of the VSS is an industry standard inasmuch as I can find the information. Perhaps someone can chime in with better information.

I forgot in my little resume posting:
A&P License (1971 Air Force) That's Airframe and Powerplant (Reciprocating)
ASET (1975, Still in USAF), ASCIS (1985, Working at HP)
BSME (1992, Excellon Automation))
MBA (2002, Intel)

Yup, used to was I could repair pretty near anything. Electrical (up to 960 3-phase Licensed (My old man was a Contractor, guess how I spend my youth)), Electronic, Mechanical, Hydraulic, Pneumatic and for that matter, Pneudraulic. I speak several computer languages as well as the popular PLC languages.

It has been an interesting life. I always want to know why something works as well as how. I stopped taking classes in 2008 (working on the PhD) s it is a tad difficult on retirement to pay for it. Also, I obtained all of my certs while working full time. During the 10 years I was on the road, I took correspondence courses. I just takes so long that way. Plus, change colleges, take different classes as what you have is not transferable due to program differences... Which is why my kid is in University full time so he does not have to go through what I did. Plus, it is a good time of the economy to be in school...
 
I mean, how many folks her know what a shorted primary fault on the engine analyzer aboard an EC-121 means?

Hint: Bad Magneto... Mandatory change, Red X fault, grounds the Aircraft.
 
So I'm looking at the LM358. VCC is 12v+ in, GND is 12v-, Input 1+ or 2+ should see the VSS#2 5v output, and the Output for 1 or 2 should then go to the ECU, and will be at VCC voltage, correct?

Easy breezy.
 
sorta correct.

LM358 VCC to 12V
LM358 GND to GND
input 1+ or 2+ to VSS signal output
input 1- or 2-: 1k ohm resistor to 5V VSS power, also 3.9k ohm resistor to GND. When you measure voltage at the 1- or 2- input you should see ~4 volts.
output 1 or 2: to ECU, will swing from 0V to 12V as the input swings from 0V to 5V.

You can leave the unused pins floating or do whatever you want with them, maybe find another circuit you want to build that needs an op-amp.
 
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