1jz Jzx81 -> Mx83 Abs

[mamba]

Refer to this post for background info: http://www.toymods.net/forums/showth...zx81+mx83+auto

What I am trying to achieve is to get the standard MX83 series 2 Grande ABS system to work after a jzx81 swap keeping the mx83 abs ecu. From the above post it is said that the speed sensor output from the auto gbox is a 10v square wave at 32 pulses per revolution. Is that the same from both the mx83's a340e and the jzx81's a341le's box? Because if this is so, shouldn't ABS work after the swap, with the only difference being that the signal that is sent back to the engine ecu (SPD2+) gets divided differently. By a factor of 32 for a340e and by 8 for a341le? Giving a 1ppr for the mx83 and a 4ppr for the jzx81?
In saying all this, dividing of the SPD2 signal is not needed as stated in the above thread as the ecu defaults to SPD if no SPD2 is detected. Leaving me with the question, what is the purpose of SPD2 in the functioning of the ABS?
From what I understand in that post is that, people have issues shifting out of first (and possibly) all gears because of this error in signal division between the 2 ABS ecu's located in the boot. So they just remove the SPD2 signal to ecu and the ecu shifts fine.
Is the only way to get the ABS system on a 1JZ MX83 working, whereby the mx83 abs ecu is maintained, by changing the speed pickup on the gbox itself? Or can the signal from the gbox to abs ecu be intercepted and manipulated to a value the abs ecu can work with? Also, the jzx81 has by my knowledge 4 speed pickups. 1 for each front wheel and instaed of just using a gearbox sensor for the rear wheels the jzx81 had a sensor on each rear wheel. Could this complicate matters? But since I'm using a mx83 abs ecu and not the jzx81's this shouldn't be too much of an issue.

Anyone who can solve this, the help would be appreciated! I can't seem to find anyone who has a working abs system on a jzx81 converted mx83. No one seems to bother, but even with a BA/R33 brake upgrade, you can't outperform abs in emergency situations.

[SillyCarS]

even with a BA/R33 brake upgrade, you can't outperform abs in emergency situations.

i love speculation

more disc/friction material means more heat dissipation meaning less chance of the pad welding to the disc = more controlled braking for longer

abs is effectively grabbing and letting go of the dsic to insure welding doesnt occur from over heating, abs increases the stopping distance and control, abs is more effective on the same size disc not necessarily though for a larger disc

for eg, my old man drives a beemer, very good brakes (supposedly). from 60 km/hr he failed to stop in time for a guy who cut him and he hit him. you could feel the car braking and then not braking quite heavily while in the vehicle

then take my room mates land-yaught r33 4 door with stock brakes (non abs) who will pull up from 60km/hr in about half the distance without locking up

EDIT: abs kicks arse on gravel,snow

[brett_celicacoupe]

i have a feeling its the tooted wheel and inductive sensor that goes into the ABS computer.

it may have been one of the pins on the engine->body loom plug which i didnt connect. the wiring diagrams floating around for the body loom plug are pretty sketchy.

i just cut up my last complete 7mge loom so i cant trace back where the speed sensor goes into the dash loom plug.

[BigWorm]

My brother (PlacentaJuan on here) has an MX83 with a 2J and the R33/BA brake upgrade with the ABS working, and it's one of the best stopping vehicles I've been in.
His members rides thread may have some info about it, I remember there was a write up on how ABS works & how brake upgrades & swaps will affect it, it has been discussed quite a bit.

[mamba]

Fair enough, agreed R33 brakes are better than mx83 abs.

BUT

This does not answer the question posted on HOWTO make it work.
I plan on doing the BA/R33 upgrade.
Based on brett's reply, the tooted wheel is one of the things that will need to be changed in order for this to work. Is there any other things?

I will try and look up that post RE the 2JZ/R33 brakes with abs,

cheers

[brett_celicacoupe]

if you leave the MX83 hubs on there then the ABS computer doesnt care what rotors/pads/calipers you have.

see if you can find me a good pinout diagram of the MX83/ JZX83 body loom plug

i had bookmarked a page on thermactor.com but it now says "account suspended"

[Mos]

Refer to this post for background info: http://www.toymods.net/forums/showth...zx81+mx83+auto

I haven't checked the thread. The below responses are from memory but should be accurate.

What I am trying to achieve is to get the standard MX83 series 2 Grande ABS system to work after a jzx81 swap keeping the mx83 abs ecu. From the above post it is said that the speed sensor output from the auto gbox is a 10v square wave at 32 pulses per revolution. Is that the same from both the mx83's a340e and the jzx81's a341le's box?

Yes it is a 10V, 32ppr square wave. Yes they are the same.

Because if this is so, shouldn't ABS work after the swap, with the only difference being that the signal that is sent back to the engine ecu (SPD2+) gets divided differently. By a factor of 32 for a340e and by 8 for a341le? Giving a 1ppr for the mx83 and a 4ppr for the jzx81?

Yes.

In saying all this, dividing of the SPD2 signal is not needed as stated in the above thread as the ecu defaults to SPD if no SPD2 is detected.

Yes (SP2, not SPD2).

Leaving me with the question, what is the purpose of SPD2 in the functioning of the ABS?

SP2 is not for the ABS, it is for the transmission ECU (located inside the engine ECU). The ABS speed sensor and ABS ECU is used to generate the SP2 signal for the transmission ECU. There is nothing stopping you from dividing the 32ppr by 8 to get the 4ppr for the 1JZ ECU.
The two sensors are there for redundancy - given they are needed for transmission shifting, you don't want a single point of failure to disable the vehicle completely. Having said that, I don't know how prone to failure the speed sensors are and I don't know how necessary two sensors really are, but that's why they're there, but they're not there for the benefit of the ABS.

From what I understand in that post is that, people have issues shifting out of first (and possibly) all gears because of this error in signal division between the 2 ABS ecu's located in the boot. So they just remove the SPD2 signal to ecu and the ecu shifts fine.

Yes. If you have an SP2 signal that is 1ppr but the ECU is expecting 4ppr than it's logical to conclude that the vehicle speed will need to be 4 times higher - the transmission will still shift out of first but that will be around 80km/h rather than the 20km/h, although most people don't find that out - they just assume it's not working at all.

Is the only way to get the ABS system on a 1JZ MX83 working, whereby the mx83 abs ecu is maintained, by changing the speed pickup on the gbox itself?

No. I don't understand why you're asking that given that it contradicts what you said above?

Or can the signal from the gbox to abs ecu be intercepted and manipulated to a value the abs ecu can work with?

From my experience the ABS sensor in the two boxes is identical, hence not requiring any sort of manipulation.

Also, the jzx81 has by my knowledge 4 speed pickups. 1 for each front wheel and instaed of just using a gearbox sensor for the rear wheels the jzx81 had a sensor on each rear wheel.

AFAIK that's incorrect. All the JZX81 transmissions I've seen use an ABS sensor in the extension housing, implying a 3 channel ABS. There may have been other versions but I haven't come across them.
Vehicles equipped with 4 channel ABS (JZS147, JZX100, etc) will use a 4ppr SP2 sensor in the extension housing of the transmission as the ABS sensors are in the hubs.

The major difference that I'm aware of is that the JZX81 incoporates traction control which utilises part of the ABS system. As far as I know the sensors are still the same, the control system is different and the hydraulics are different.

Could this complicate matters? But since I'm using a mx83 abs ecu and not the jzx81's this shouldn't be too much of an issue.

Anyone who can solve this, the help would be appreciated! I can't seem to find anyone who has a working abs system on a jzx81 converted mx83. No one seems to bother, but even with a BA/R33 brake upgrade, you can't outperform abs in emergency situations.

I believe there are several converted MX83s with working ABS.

Mos.

[mamba]

Mos, going by your reply,

SP2 is for redundent use only, no significant value other than backup.
Both gearboxes sends the same signal to abs ecu, therefore no change is required there.
jzx81 only has 3 speed sensors from the wheels for abs. (Does mx83 have the same?)
Since i'm not using the jzx81 abs ecu, traction control is not applicible hence why the mx83 abs ecu should be fine.

So going off that, with SP2 unpluged, which I believe it is, or else my car will shift at some ridiculous speed, my abs should work as is??

Or am I missing something here?

[Mos]

Mos, going by your reply,

SP2 is for redundent use only, no significant value other than backup.

Yes but no. I think you're slightly missing the point.
SP2 is the primary for the transmission. SPD is the primary for speedo and engine ECU, and redundant (backup) transmission speed sensor.
You can think of SP2 as redundant but strictly speaking that's not correct, although it works - strictly speaking it's not a backup for anything, just primary for something that has a backup.

Both gearboxes sends the same signal to abs ecu, therefore no change is required there.

Yes.

jzx81 only has 3 speed sensors from the wheels for abs. (Does mx83 have the same?)

2 sensors from the wheels, 3rd sensor from the transmission representing the rear axle.
Yes.

Since i'm not using the jzx81 abs ecu, traction control is not applicible hence why the mx83 abs ecu should be fine.

Yes.

So going off that, with SP2 unpluged, which I believe it is, or else my car will shift at some ridiculous speed, my abs should work as is??

Yes, provided it's all hooked up bar SP2 from the ABS to engine/transmission ECU, but it will still flash the O/D Off light.

Or am I missing something here?

You might be but sounds fine.
If it's all hooked up and not working I'd be scoping signals first, and if they're all present then start looking elsewhere. I wouldn't start looking elsewhere first.

Mos.

[mamba]

SP2 is the primary for the transmission. SPD is the primary for speedo and engine ECU, and redundant (backup) transmission speed sensor.
You can think of SP2 as redundant but strictly speaking that's not correct, although it works - strictly speaking it's not a backup for anything, just primary for something that has a backup.

I get that now, thanks

Yes, provided it's all hooked up bar SP2 from the ABS to engine/transmission ECU, but it will still flash the O/D Off light.

I sure hope there's a workaround to this, as my O/D light is flashing atm.
Can't say I've persued it as of yet. Still have to speak to Brett about it too, he's been the guru on my car so far. But would love to get it to stop flashing at me.

[Gavatron]

This thread saves you answering my PM Mos

O/D off flashing solution = take O/D off globe out

[madmont]

I put a 2JZGE auto from a Supra (with Aristo sump) into my Grande and retained the Grande ABS rotor and sensor and extension housing and it works ok. No blinking lights.
http://toymods.net/forums/showthread...908#post455908

[Gavatron]

Got another question regarding JZX81 into MX83 and ABS. more specifically the loom across the underside of the radiator support that goes to the headlights, ABS actuators and the alternator and right hand side of the motor.

Can I just swap this whole loom into the MX83 and still have working ABS, headlights, alternator, hydro fan etc?