3.7L V6 QT1 to QT2 Conversion.

[cmdr jim]

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).

Unplugging wheel switches is easy enough to do, I'm thinking it will go into a ABS error of some sort, but it's a quick test.
Do you think there is there a way to tap into a wheel sensor to see what signal is being sent to the ABS module?

[Matt]

There is a way to tap into the signal.... but that's the easy part and doesn't answer the question of what the ABM is doing with the signal. If its just counting pulses there's no problem, whereas if its analyzing the waveform (probable for present day electronics) then we'll have an issue.

I guess the only way we'll really know is to test it out like you drew up......

[cmdr jim]

I think you are right, testing it may be the only way....another $80.

Getting back to your manually locking ELSD question. Keep in mind, I don't have all the electronic features to lock and unlock the differentials as you do with the FDCM. The ELSD is electro-hydraulic operated, and applies a pressure to a clutch pack. Your Jeep uses a PDM to control voltage to the solenoid to vary the pressure on the clutch pack and does this as required for the different inputs it is receiving from the wheel sensors, engine, transmission, etc. It also monitors the resistance to determine how hot the differential is getting and will back off on the useage if it gets too hot. A lot is going on there.

I have done a number of test on a soleniod out of the ELSD and it is high temperature rated, over 350 degrees F. I have tried to kill it with time, but at over an hour of on time and temperatures stabilizing around 300 F, I couldn't. I started testing with an adjustable PDM but found out shorty, it's not needed if all I'm going to do is apply full pressure to the clutch pack. For my use, it's really quite simple. I am going to use a 12vdc voltage regulator and a relay and switch. The solenoid pulls under 1 amp at 12vdc (I could probably get by without the relay) Then just turn it on with the switch when needed and shut it off when not. The key here is not to keep it energized for more than 20 to 30 minutes to stay away from any heat issues.

If you wanted, I would start a test by just unplugging both your front and rear ELSD solenoid wires and shut off Traction Control and see what errors you get. If you get some, plug the wires back in and drive it, see when the errors go away. If they do, your next step would be to find a DPDT relay or use 2 relays. I think you want to disconnect both the positive and negative wires going to the FDCM from the ELSD solenoid when powering it with straight 12vdc. Nothing getting back to the FDCM period.

In the picture I show the solenoid hooked up to a power supply, shortly after that picture I had to hang the solenoid from the desk or it would have burned the desk. I ran numerous tests and couldn't kill it with duration or temperature.

[Matt]

I was following you ELSD thread... I believe on the commander forum?

Agreed, there are a lot more limitations from my end. Probably worthy of a whole new thread.

Since its more of a "nice to have", I think energy should stay focused on the QTII tcase conversion. Not to mention, the results if your testing could be the solution for manually controlling the ELSDs on vehicles already equipped. In case the idea didn't already pop into your head..... we may be able to trick the computer in thinking one front and one rear wheel is slipping so it engages the diff. (Unknown would be if we get errors after diff is engaged and wheel speeds are still off.... lol another thread for that)

[cmdr jim]

Yup, on the other forum....

I ordered a SGI-5 and am planning on testing next week some time. I think at first I will set it up to run on only one wheel sensor. I can have it condition the signal at a ratio of 1 to 1. If it functions properly I'll add in the other 3 wheel senors and test Low Lock.

My email back from Dakota states there are two possible outputs from the SGI-5:

Technically all of the outputs on that unit are a square wave. *The difference on them being the A/C outputs are above and below ground (-6V to +6V), and the open collector outputs will be all above ground with voltage dependant on the pull-up provided (0V-12V if a 12V pull-up).

So as long as the ABM isn't looking for something other than these two types of input it should work....

[cmdr jim]

The SGI-5 came in yesterday, I hooked it up to a front wheel sensor and I can't get it to see a signal. I went through the troubleshooting section of the manual, I get a constant green light on the SGI-5, which means no signal. I tried all the changes suggested in the manual and could not get a signal from the wheel sensor. Also while running off the SGI-5 without a signal, the anti-lock brake error and no traction control lights came on immediately and stayed on until I reconnected the wheel sensor back to normal. My guess is the wheel sensor is sending a signal the SGI-5 doesn't recognize.
I think I'm back to setting up a wheel sensor to switch to when in Low Lock.

I have an email into Dakota Digital tech support.

[Matt]

That's strange.... the signal of the speed sensor shouldn't be anything fancy. You went for a test drive with it?

Did you maintain the input voltage for the sensor and just tap into the return signal?

[cmdr jim]

That's strange.... the signal of the speed sensor shouldn't be anything fancy. You went for a test drive with it?

Did you maintain the input voltage for the sensor and just tap into the return signal?

Yes and Yes. I did find this explanation of "Active WSS Sensors" on the internet this morning, which may shed light to why the SGI-5 can not see a signal.

ACTIVE WSS SENSORS
In recent years, several new types of “active” WSS sensors have appeared. These are used on many 1999 and newer Chrysler, Jeep and Mercedes models with Teves Mark 20e and up Teves ABS systems. Active WSS sensors are also found on the Ford Focus, Toyota Tundra and other applications. This type of sensor is becoming more common on late-model vehicles because of its greater accuracy at low speeds.
Active WSS sensors, which Chrysler refers to as “magneto-resistive” sensors, work like a “Hall effect” sensor and generate a square wave on-off digital signal that changes frequency with wheel speed. This type of sensor detects the change in magnetic polarity (flux) as the teeth on the tone ring or small magnets pass under it. Small magnets may be built into the wheel bearings or bearing seal for the WSS sensor to read.
Active sensors often have three wires: a voltage reference input (5 to 12 volts), a signal output and ground. But some active sensors have only two wires (reference voltage and signal return).
How can you tell a 2-wire active sensor from a 2-wire passive sensor? Turn the ignition on and backprobe both wires with a voltmeter. If you see a voltage reading (5 to 12v), you have an active WSS sensor. If you see no voltage (0v), you have a passive WSS sensor.
Active WSS sensors also have an integrated circuit within the sensor itself that converts and amplifies the signal before it goes back to the control module. This allows the sensor to read wheel speeds all the way down to zero mph (which improves ABS control at low speeds as the vehicle comes to a halt).
When the key is on, an active WSS sensor has two states: low and high. In the low state, it generates a fixed 0.9 volt return signal of about 7 milliamps. In the high state, it generates a signal of 1.65 volts and 14 milliamps. The rate at which it toggles back and forth between its high and low states corresponds to the speed of the wheel.
This type of sensor must be connected to its wiring harness to test it, and the ignition key must be on so the control module can provide reference voltage to the sensor. If you forget and leave the key off, you won’t get any output from an active WSS sensor.
Because of the added electronic circuitry inside the sensor, and active WSS sensor cannot be tested with an ohmmeter like a passive WSS sensor. You have to look at its output signal when the wheel is turning and the ignition is on. This can be done with a scan tool (look for a mph reading while spinning the tire or during a test drive), with a voltmeter (turn the wheel very slowly and look for a change in the voltage output from high to low), with a NOID light (the LEDs on the NOID light will flash when it detects a signal pulse), or a DSO. The waveform on the scope should show a square wave pattern that changes from low (0.9v) to high (1.65v) as the wheel turns. The difference in height of the waveform should be 0.75 volts (1.65v minus 0.9v).

[07JeepXK]

It's been awhile. Any updates on this????

[cmdr jim]

It's been awhile. Any updates on this????

Working too much overtime and it's been on the back burner till I have time to address it. The SGI-5 didn't work for conditioning the wheel speed sensors. These sensors are the newer Chrysler type and the SGI-5 doesn't put out the correct signal.
I have an idea of placing an additional speed sensor at the front differential and switch to it when in low, but the speed sensor would be 2% off from real and I don't know what the Jeep will do with 2%. Plus it would feed all 4 wheel locations, so being fully locked up would be needed. Or figure out how to place individual sensors and tong rings at each corner, switching to those when in low.
Other than that, I can use low, but it puts the transmission into third gear quickly and if I shift to park or neutral, I lose all gears and have to put the transfercase back into high to fix it. Then it drives normally, until I repeat going into low. I do have a fully locking high which is nice.....