R32 Abs Problem

[zac the muss]

Ive been having a bit of trouble with my ABS since swapping to an R33 diff and making up a mount for the 32 ABS sensor.

I was working fine before the swap but now i find the brake pedal is unusually firm and really standing on it will give concerningly low stopping power. Then after about 5 minutes the ABS light comes on, stopping power returns to normal, just there is no ABS.

This only happens at motorway speeds, at 50k's everything works as it should

There is just under 1mm gap form the sensor tip to the ABS ring

I must be missing something

Help anyone??

[zac the muss]

can anyone shed some light on this?

[GTSBoy]

Take it to a workshop with a decent scan tool and look for codes in the ABS computer.

[zac the muss]

Has anyone got a list of error code for the R32 gtst computer? i managed to pull over while the ABS was playing up and counted 10 flashes between pauses. im assuming error code 10?

[datsun_1600]

I'm not sure about this at all - but are the number of teeth on the R33 diff different to the R32's ? That would cause the computer to think the rear wheels were turning at a speed than the front wheels

[datsun_1600]

Or even a different material could cause it too (ie capacitive vs hall effect sensor) Just spit balling, but if the R32 ones were alloy and the R33 teeth were steel, then that would be an issue, you would have to change the sensors over too. (doubt they would be compatible though)

[zac the muss]

Thats a point, but i used the driveshaft flange off the old R32 diff so same ring.

It uses the original sensor aswell, so the only change i can see is position of the sensor/distance from ABS ring.

R33 abs diffs are completely different as they have sensors either side of the diff on the output shafts.

Edited June 7, 2013 by zac the muss

[zac the muss]

Could the change in ratio have anything to do with it?

went from 4.363 to 4.11.

note it only happens over 100 k's

[GTSBoy]

Diff ratio change might actually be the problem.........front ABS rings are still going around at the same speed they used to.....but now the rear one is going around slower. That might be enough to freak the ABS computer right out.

You might have to look into putting an R33 ABS system into it!!! eeek.

[zac the muss]

thats just what i was thinking. Im going from a 40 to a 45 profile tyre on the front so hopefully that might make a difference.

[GTSBoy]

Or just piss off the ABS. Would be my choice. No driver aids left in my car at all now. Auto is gone, HICAS is gone. If it had had ABS that would also be gone now.

[zac the muss]

ABS is a nice thing to have when your at the end of the back straight of pukekohe.

[GTSBoy]

Why? If you know you're going to have wheel lock, then you are prepared to modulate the pedal, no? ABS is intended for those crash stop moments on the road with drivers who don't know what they're doing at the best of times, let alone when they are surprised. If you're driving a car on the race track, you are at the opposite end of the spectrum from where ABS is intended to be used.

Edited June 8, 2013 by GTSBoy

[zac the muss]

It's more so joe blow can steer around an obstacle while still hard on the brakes. Anyway, 45profile tyres are mounted up, we.ll see if this makes a difference

[zac the muss]

well, the abs is behaving itself again. must have been a too bigger speed difference with the taller diff ratio and different tyre sizes