3.7L V6 QT1 to QT2 Conversion.

[cmdr jim]

Cool, stick with the Masters program. I've been designing automated equipment for 20+ years, I wish I had stuck with it when I had the chance.

[Matt]

I hear ya. I'm trying to knock it out before the kids get old enough for sports and I really have no time!

[ScorpionCrawler]

This has been a fun read, I'm maybe getting 30% of what you are saying but am hoping for the day that you say it's dialed in the way you want it to be.
Great build, great thread, keep up the good work and info and GOOD LUCK!!

[Matt]

Ok there's definitely a few options but we have to do a bit of homework to determine which are viable. It all depends on what the computer is doing with the signal. If the computer is "dumb" and only cares about pulses (on/off/on/off/etc) then there are some simpler options. However, like eluded to in the Dakota Digital link, the computer may be analyzing the entire signal- not just PPM but other parameters such as pulse width which would be affected by some simpler conditioning methods.

So we'd have to check the schematics to see where the speed sensor signals are going (which modules) and try to figure out what the module(s) are looking for.

**something quick/fun to try that would only help someone with controllable lockers; what would happen if all 4 sensors are unplugged? Wondering if that would prevent limp mode and just throw ABS/TCS lights, thereby allowing you to wheel in 4-low?

[cmdr jim]

Here is a bit more information from the service manual about the Wheel Sensors:

SENSOR-FRONT WHEEL SPEED
DESCRIPTION
A wheel speed sensor is used at each wheel. The front sensors are mounted to the steering knuckles. The rear
sensors are mounted at the outboard end of the axle. Tone wheels are mounted to the outboard ends of the front
and rear axle shafts. The gear type tone wheel serves as the trigger mechanism for each sensor.
OPERATION
The sensors convert wheel speed into a small digital signal. The ABM sends 12 volts to the sensors. The sensor
has an internal magneto resistance bridge that alters the voltage and amperage of the signal circuit. This voltage
and amperage is changed by magnetic induction when the toothed tone wheel passes the wheel speed sensor. This
digital signal is sent to the ABM. The ABM measures the voltage and amperage of the digital signal for each wheel.

Not sure what this all means.

[Matt]

That's not really saying much...

The sensors convert wheel speed into a small digital signal.

I'm sure you know this already, but others might not.
This just says what the sensor does.... wheel speed means the tone ring is rotating, as it rotates the sensors reads that and creates the digital signal which is merely a square waveform.

The ABM sends 12 volts to the sensors. The sensor has an internal magneto resistance bridge that alters the voltage and amperage of the signal circuit. This voltage and amperage is changed by magnetic induction when the toothed tone wheel passes the wheel speed sensor.

This is just the written description of the hall effect sensor. The magnetic field changes as the teeth of the tone ring pass.... on/off/on/off/on/off/etc. The change in magnetic field takes the standard input voltage and creates a fluctuating output. It's this output (voltage and magnitude) that we need to figure out..

This digital signal is sent to the ABM. The ABM measures the voltage and amperage of the digital signal for each wheel

The bold is the important part.... the voltage and amperage measurements indicate the module is concerned with more than just the number of pulses in a given period of time. This would make sense now that I think about it since there are DTC's for high/low sensor voltage....

[cmdr jim]

Here is the Wheel Sensor Schematic and the SGI-5 wiring diagram. I assume it's a matter of cutting the wheel sensor signal wire to the signal input of the SGI-5 and then connecting the the ABM side to the Out1 or Out2.
Most of the electrical diagnostics are checking wheel sensors deals with for voltage above 10vdc, and shorts to ground or voltage. Matt pm me with your email and I'll send you a pdf of of the section to look at if you're interested.

[Matt]

Just checked out some of the info.... im still iffy due to the way our vehicles use the signal. I'd contact them and ask for specifics on why they don't recommend using their device for ABS signals. I presume it has to do with some of the concerns my professor brought up today; specifically if the module is reading the leading & trailing edges of the waveform and using frequency calculations to determine wheel speed as opposed to the number of pulses. Amplitude calculations of the output waveform will also give an indication that the input voltage is compromised.

[cmdr jim]

Just checked out some of the info.... im still iffy due to the way our vehicles use the signal. I'd contact them and ask for specifics on why they don't recommend using their device for ABS signals. I presume it has to do with some of the concerns my professor brought up today; specifically if the module is reading the leading & trailing edges of the waveform and using frequency calculations to determine wheel speed as opposed to the number of pulses. Amplitude calculations of the output waveform will also give an indication that the input voltage is compromised.

I'm iffy as well, I just don't understand the way the signal is process. However I do think it's a liability issue for Dakota and for them to state it is not to be used with ABS takes them out of that situation.
My plan was never to use the controller for on road use. For off road use only per my first post. With the controller power turned off for on road use. That would be the same for the SGI-5, no signal conditioning for on road use, which would not influance ABS. I don't thing we need anti-lock brakes running at low speeds offroad, if signal conditioning would affect it.

I sent you another email, showing the way I would go forward testing with a single SGI-5 and 4 relays to allow my PLC program to switch between stock wheel sensor signals and conditioned signal. Going farther, it would require a SGI-5 for each wheel sensor to maintain Traction Control.

[Matt]

It's not really a matter of "needing" ABS or a liability im concerned about... its how the signal is processed and what sending a modified waveform into the ABM will do. You may find you'll do all this work and end up with limp mode again; in which case you may be better off just disconnecting the sensors (figuratively with a switch).