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-   -   TCS & DSC Info/Questions (https://www.rx8club.com/series-i-tech-garage-22/tcs-dsc-info-questions-17570/)

moatz 07-14-2004 04:45 PM

Firstly, sorry to drag up an old post.

I have just been the unlucky recipient of a faulty "ABS pump" (service desk term). I assume this to be the ABS Hydraulic Unit / Control module.

The first sympton I noticed was that when I started my car the DSC was automatically disabled (the DSC, slippery when wet, light and the ABS light were permentantly on). The second symptom was that after the car was moving te park brake light would re-appear (yes, the park brake was dis-engaged).

Also, I had a definite brake "whistling" before this happened, when the safety systems shut themselves down the "whistling" was gone. So , hushler if you are still around, from my experiences, you are not crazy.

BTW, I have had the car 7 months and I've drivien 14.5K miles in the vehicle.

beachdog 07-14-2004 05:16 PM

Quote:
I have just been the unlucky recipient of a faulty "ABS pump" (service desk term). I assume this to be the ABS Hydraulic Unit / Control module.

My ABS Module was replaced at 4700 miles. The most significant symptom aside from the light show on the dash was that the power steering failed.

See this thread:
https://www.rx8club.com/series-i-tech-garage-22/pseudo-power-steering-failure-long-post-32389/

rotaryPilot 01-28-2008 08:26 AM

Well concerning the TCS :

How does it actually works?

1) Cutting the throttle (as letting the gas petal) ?
2) Cutting the fuel in second rotor (like rev limiter) ?


If the no 2 is the case, I guess that in FI RX-8 fuel starvation may take place. Just imagine to accelerate with 6000+ with 4th gear and due to a lot of power (forced induction) your wheels start to spin, then you have forgotten to take off the TCS and ECU starts to cut off fuel on the second rotor. I guess then you have a fuel starvation problem.

All the above IF the No 2 applies.

MazdaManiac 01-28-2008 09:35 AM

The rev limiter doesn't cut fuel to just the second rotor, so this isn't an issue. (It just slams the DBW throttle down to 40%.)

The TCS pulls throttle and squeezes the rear brakes in response to the wheels speed sensor differential. DSC pulls throttle and squeezes all four brakes asynchronously in response to the yaw sensor.

nycgps 01-28-2008 10:13 AM

2004 thread has came back to life !

rotaryPilot 01-30-2008 01:26 AM


Originally Posted by MazdaManiac (Post 2266533)
The rev limiter doesn't cut fuel to just the second rotor, so this isn't an issue. (It just slams the DBW throttle down to 40%.)

The TCS pulls throttle and squeezes the rear brakes in response to the wheels speed sensor differential. DSC pulls throttle and squeezes all four brakes asynchronously in response to the yaw sensor.

Thanks for the response. Sorry for the following stupid questions :

1) what is DBW?
2) Is there any technical paper to back up your opinion about rev limiter and TCS/DSC that the throttle is being manipulated and not a direct fuel cut off ?

MazdaManiac 01-30-2008 01:43 AM

DBW = Drive By Wire

Technical paper? We have datalogs.
When you hit the limiter, the throttle closes.
That AFR actually gets more rich, not lean.

whitebeau 01-30-2008 04:08 AM

Alternative Explenation.

Throttle/Gas pedal control is completely electronic, it takes the percentage of the pedal depression, then takes in sensor factors of TCS & DSC (Provided they are enabled) then allows rpm acceleration by managing ignition & Fuel timing. all done within milliseconds.

... Brings a whole new meaning to TPS reports (Office Space) .. no not Tire Pressure sensor :)

MazdaManiac - Dude were do you get those pics? ;)


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